NTDPJTV04
SERVICE TRAINING
"Customer Satisfaction Through Knowledge"
SERVICING THE N5SS
COLOR TELEVISION
CHASSIS / DIGITAL
CONVERGENCE
TOSHIBA AMERICA CONSUMER PRODUCTS, INC.
NATIONAL SERVICE DIVISION
TRAINING DEPARTMENT
1420-B TOSHIBA DRIVE
LEBANON, TENNESSEE 37087
PHONE: (615) 449-2360
FAX: (615) 444-7520
FOREWORD
The material presented in this manual is provided for the technical training of TACP employees and
qualified service personnel only.
The specific circuit reference designations, pin numbers, etc., are taken from the TP48E50/60 Service
Manual, File Number 020-9508. The diagrams in this manual are simplified for training and should be used
as a reference guide only when servicing the N5SS CTV Chassis. Refer to the applicable service data for
detailed adjustment and servicing procedures.
NTDPJTV04
SERVICING TOSHIBA'S N5SS TELEVISION CHASSIS
©1996
TOSHIBA AMERICA CONSUMER PRODUCTS, INC.
National Service Division
National Training Department
1420 Toshiba Drive
Lebanon, TN 37087
(615) 449-2360
No part of this manual may be reproduced in whole or in part without prior written consent from
Toshiba America Consumer Products, Inc., Service Division.
CONTENTS
SECTION I
OVERALL UNIT CHARACTERISTICS,
BLOCK DIAGRAMS, LABS 1 & 2
1. MAIN FEATURES .................................. 1-2
2. MERITS OF BUS SYSTEM .................... 1-2
2-1. Improved Servciceability ................. 1-2
2-2. Reduction of Parts Count ................ 1-2
2-3. Quality Control ................................. 1-2
3. COMPARISON/DIFFERENCES TG-1 ... 1-2
4. SPECIFICATIONS .................................. 1-3
5. FRONT AND REAR CONTROL
VIEWS ..................................................... 1-4
5-1. Front View ........................................ 1-4
5-2. Rear View ......................................... 1-5
5-3. Remote Control View ....................... 1-6
6. '95 PJ-TV CHASSIS LAYOUT ............... 1-7
7. CONSTRUCTION OF CHASSIS............ 1-8
8. VIDEO SIGNAL FLOW. ....................... 1-9
9. AUDIO SIGNAL FLOW. ...................... 1-11
10. POWER SUPPLY .................................. 1-12
11. H and V DEFLECTION. ........................ 1-13
12. I2C COMMUNICATIONS. .................... 1-14
13. DIGITAL CONVERGENCE. ................ 1-15
14. LAB 1 ..................................................... 1-16
15. LAB 2 ..................................................... 1-20
SECTION II
TUNER, IF/MTS/S.PRO MODULE
1. CIRCUIT BLOCK.................................... 2-2
1-1. Outline .............................................. 2-2
1-2. Major Features .................................. 2-2
1-3. Audio Multiplex Demodulation
Circuit ............................................... 2-3
1-4. A.PRO Section (Audio Processor) ... 2-4
2. PIP TUNER .............................................. 2-6
2-1. Outline ............................................... 2-6
SECTION III
CHANNEL SELECTION CIRCUIT
1. OUTLINE OF CHANNEL
SELECTION CIRCUIT SYSTEM .......... 3-2
2. OPERATION OF CHANNEL
SELECTION CIRCUIT ........................... 3-2
3. MICROCOMPUTER ............................... 3-3
4. MICROCOMPUTER TERMINAL
FUNCTION .............................................. 3-4
5. EEPROM (QA02) .................................... 3-6
6. ON SCREEN FUNCTION ....................... 3-6
7. SYSTEM BLOCK DIAGRAM ................ 3-7
8. LOCAL KEY DETECTION METHOD .. 3-8
9. ENTERING THE SERVICE MODE ....... 3-9
10. TEST SIGNAL SELECTION .................. 3-9
11. SERVICE ADJUSTMENT ...................... 3-9
12. FAILURE DIAGNOSIS PROCEDURE 3-10
13. TROUBLE SHOOTING CHARTS ....... 3-13
SECTION IV
AUDIO OUTPUT CIRCUIT
1. OUTLINE ................................................. 4-2
2. THEORY OF OPERATION .................... 4-2
2-1. Operation of TA8256H .................... 4-2
SECTION V
DSP CIRCUIT
1. ORIGINS OF DOLBY SURROUND ...... 5-2
2. THE DOLBY MP MATRIX .................... 5-2
3. THE DOLBY SURROUND
DECODER ............................................... 5-3
4. DSP CIRCUIT .......................................... 5-3
5. DSP (Digital Surround Processor) IC ...... 5-6
SECTION VI
A/V SWITCHING CIRCUIT
1. OUTLINE ................................................. 6-2
2. IN/OUT TERMINALS ............................ 6-2
3. CIRCUIT OPERATION .......................... 6-2
3-1. Composite Video Signal ................... 6-2
3-2. S-Video Signal ................................. 6-2
SECTION VII
VIDEO PROCESSING CIRCUIT
1. OUTLINE ................................................. 7-2
2. SIGNAL FLOW ....................................... 7-2
3. CIRCUIT OPERATION .......................... 7-2
SECTION VIII
V/C/D/IC
1. OUTLINE ................................................. 8-2
2. LARGE SCALE EMPLOYMENT OF
BUS CONTROL OF PARAMETER FOR
PICTURE CONTROLS ........................... 8-2
3. EMPLOYMENT OF CONTAINING
EACH VIDEO BAND FILTER
INSIDE ..................................................... 8-2
4. EMPLOYMENT OF CONTAINING
EACH FILTER (FOR S/H) INSIDE ....... 8-2
5. LOW COST OF IC .................................. 8-3
SECTION IX
PIP MODULE
1. BOARD LAYOUT ................................... 9-2
2. SIGNALS ................................................. 9-2
3. BLOCK DIAGRAM ................................ 9-3
SECTION X
SYNC SEPARATION, H-AFC,
H-OSCILLATOR CIRCUITS
1. SYNC SEPARATION CIRCUIT .......... 10-2
1-1. Theory of Operation ....................... 10-2
2. H AFC (Automatic Frequency Control)
CIRCUIT ................................................ 10-3
3. H OSCILLATOR CIRCUIT .................. 10-4
3-1. Outline ............................................ 10-4
3-2. Theory of Operation ....................... 10-4
SECTION XI
VERTICAL OUTPUT CIRCUIT
1. OUTLINE ............................................... 11-2
1-1. Theory of Operation ....................... 11-2
2. V OUTPUT CIRCUIT ........................... 11-3
2-1. Actual Circuit ................................. 11-3
2-2. Sawtooth Waveform Generation .... 11-3
2-3. V Output ......................................... 11-4
2-4. V Linearity Characteristic
Correction ....................................... 11-6
3. PROTECTION CIRCUIT FOR
V DEFLECTION STOP ........................ 11-7
3-1. +35V Over Current
Protection Circuit ........................... 11-8
SECTION XII
HORIZONTAL DEFLECTION CIRCUIT
1. OUTLINE ............................................... 12-2
2. HORIZONTAL DRIVE CIRCUIT ........ 12-2
2-1. Theory of Operation ....................... 12-2
3. BASIC OPERATION OF HORIZONTAL
DRIVE .................................................... 12-3
3-1. Theory of Operation ....................... 12-3
3-2. Drive System .................................. 12-4
3-3. Circuit Description ......................... 12-5
4. HORIZONTAL OUTPUT CIRCUIT .... 12-6
4-1. Theory of Operation ....................... 12-7
4-2. White Peak Bending
Correction Circuit ......................... 12-11
4-3. H Blanking ................................... 12-12
4-4. 200V Low Voltage Protection ...... 12-13
5. HIGH VOLTAGE GENERATION
CIRCUIT .............................................. 12-14
5-1. Theory of Operation ..................... 12-14
5-2. Operation Theory of the Harmonic
Non-Resonant System and Tuned
Waveforms ................................... 12-16
6. HIGH VOLTAGE CIRCUIT ............... 12-17
6-1. High Voltage Regulator................ 12-17
7. X-RAY PROTECTION CIRCUIT ...... 12-20
7-1. Outline .......................................... 12-20
7-2. Operation ...................................... 12-20
8. OVER CURRENT PROTECTION
CIRCUIT .............................................. 12-21
8-1. Outline .......................................... 12-21
8-2. Operation ...................................... 12-21
SECTION XIII
DEFLECTION DISTORTION
CORRECTION CIRCUIT (DPC Circuit)
1. DEFLECTION DISTORTION
CORRECTION IC (TA8859P) .............. 13-2
1-1. Outline ............................................ 13-2
1-2. Functions and Features ................... 13-2
1-3. Block Diagram ............................... 13-2
2. DIODE MODULATOR CIRCUIT ........ 13-3
3. ACTUAL CIRCUIT ............................... 13-4
3-1. Basic Operation and Current Path .. 13-5
SECTION XIV
CLOSED CAPTION/EDS CIRCUIT
1. OUTLINE ............................................... 14-2
2. DATA TRANSMISSION FORMAT ..... 14-2
3. DISPLAY FORMAT ............................. 14-3
4. CIRCUIT OPERATION ........................ 14-4
SECTION XV
DIGITAL CONVERGENCE CIRCUIT
1. OUTLINE ............................................... 15-2
2. CIRCUIT DESCRIPTION ..................... 15-2
2-1. Configuration.................................. 15-2
2-2. Circuit Operation ............................ 15-2
3. PICTURE ADJUSTMENT .................... 15-4
3-1. Change of Memory (E2PROM) ...... 15-4
3-2. Service Mode .................................. 15-4
4. ADJUSTING PICTURE
DIMENSION (Green picture) ................ 15-6
5. KEY FUNCTION OF REMOTE CONTROL
UNIT ...................................................... 15-7
6. CONVERGENCE OUTPUT
CIRCUIT ................................................ 15-8
6-1. Outline ............................................ 15-8
6-2. Circuit Description ......................... 15-8
7. CONVERGENCE TROUBLESHOOTING
CHART................................................. 15-10
8. LAB 3 ................................................... 15-11
SECTION XVI
OPTICAL SECTION
1. NECK COMPONENTS ......................... 16-2
1-1. Outline of Components Around
Neck of The Projection Tube ......... 16-2
1-2. Theory of Operation ........................ 16-2
1-3. Projection Tube .............................. 16-3
2. FUNCTION OF KEY
COMPONENTS ..................................... 16-4
2-1. Outline ............................................ 16-4
2-2. Theory of Operation ....................... 16-4
2-4. Optical Coupling Effect ................. 16-8
2-5. Lens ................................................ 16-9
2-6. Focus Adjustment ......................... 16-10
SECTION XVII
POWER CIRCUIT
1. OVERVIEW ........................................... 17-3
2. RECTIFYING CIRCUIT AND
STANDBY POWER SUPPLY .............. 17-4
3. MAIN SUPPLY CIRCUIT .................... 17-4
4. OUTLINE OF CURRENT RESONANT
TYPE SUPPLY ...................................... 17-4
5. FUNDAMENTAL THEORY ................ 17-5
6. ACTUAL CIRCUIT ............................... 17-6
7. SCAN DERIVED VOLTAGES............. 17-8
8. PROTECTOR MODULE (Z801) .......... 17-9
9. SUB POWER SUPPLY ....................... 17-10
10. PROTECT CIRCUITS ......................... 17-11
11. LAB 4 ................................................... 17-15
SECTION XVIII
DYNAMIC FOCUS CIRCUIT
1. OUTLINE ............................................... 18-2
2. H DYNAMIC FOCUS CIRCUIT .......... 18-2
2-1. Theory of Operation ....................... 18-2
2-2. Circuit Operation ............................ 18-3
3. V DYNAMIC FOCUS CIRCUIT .......... 18-4
3-1. Theory of Operation ....................... 18-4
3-2. Circuit Operation ............................ 18-5
SECTION I
OVERALL UNIT
CHARACTERISTICS
BLOCK DIAGRAMS
LABS 1 & 2
1-1
SECTION I
OVERALL UNIT
CHARACTERISTICS
1. MAIN FEATURES
3. COMPARISON/DIFFERENCES OF TG-1
CHASSIS
The main feature of Toshiba's projection television model
TP48E60, is the use of the N5SS (TG-1C) chassis. This
chassis utilizes a bus control system, developed by PHILIPS
Corporation, called the I2C (or IIC) bus. IIC stands for InterIntegrated Circuit control. This bus co-ordinates the transfer
of data and control between ICs inside the Television. It is a
bi-directional serial bus consisting of two lines, namely SDA
(Serial DATA), and SCL (Serial CLOCK).
Toshiba's concept for the TG-1 chassis was to create a sort
of universal chassis which, with minimal changes, could be
used as a standard throughout the entire Toshiba color
television lineup starting in 1995. TG-1 stands for "Toshiba
Global 1". The TG-1 chassis can be found in several
different models and varies in both complexity and features.
Digital data which is passed along the bus is received by
individual devices and can be either command or data.
Digital-to analog converters are also found within some of
the ICs, allowing them to be addressed and controlled by
strings of digital instructions, replacing those functions
which were previously implemented by external
potentiometers.
Root
Chassis
N5E
N5ES
N5S
N5S
N5SS
TG-1
Chassis
A1
A2
A2 - LEM
B
C
Typical
Sizes
13, 19
20, 32
20, 32
27, 32
27 thru 35
Typical Chassis Exam ples
Model
TG-1
CF13E22,23
A1
CF19E22
A1
CF20E30
A1
CF20E40
A1
CN27E55
A2
CF30E50
A2
CF32E50
A2
CF32E55
A2
CX32E60
B
CX32E60
B
CN27E90
C
CX32E70
C
CN32E90
C
CN35E15
C
TP48E50,51
C
TP48E60,61
C
TP55E50,51
C
TP55E80.81
C
TP61E80
C
TP48E90
C
2. MERITS OF THE BUS SYSTEM
2-1. Improved Serviceability
Most of the adjustments previously made by resetting variable
resistors and/or capacitors can be made on the new chassis
by operating the remote control and seeing the results on the
television screen. This allows adjustments to be made without
removing covers on the unit thus increasing servicing speed
and efficiency.
2-2. Reduction of Parts Count
The use of digital-to-analog converters built into the ICs,
allowing them to be controlled by software, has eliminated
or reduced the requirement for many discrete parts such as
potentiometers and trimmers, etc.
2-3. Quality Control
The central control of adjustment data makes it easier to
understand, analyze, and review the data, thus improving
the quality of the product.
1-2
Picture and
Features
Less
More
4. SPECIFICATIONS
CHASSIS
MODEL Nbr
C
C
C
C
C
C
TP48E50
TP48E51
TP48E60
TP48E61
TP48E90
TP55E50
TP55E51
TP55E80
TP55E81
TP61E80
STEP-UP
SPECIFICATION
*
G
E
N
E
R
A
L
*
S
O
U
N
D
1 Picture Size#
2 Channel Capacity
3 C. Caption
4 MTS with dbx
5 Bass, Tre/Balance
6 Sub-Audio-Program
7 Remote Control
8 Picture-in-Picture
9 LED Indicator (RED)
10 Local Key
48"-D/S
48"-D/S
48"-D/S
55"-D/S
55"-D/S
61"-D/S
181ch
181ch
181ch
181ch
181ch
181ch
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
*A-Uni (42k A-Uni (42k *Intelig+EZ A-Univ (42k A-Univ (43k A-Univ (43k
* ● (1TN)
● (2TN)
● (2TN)
● (1TN)
● (2TN)
● (2TN)
● (P)
● (P)
● (P)
● (P)
● (P)
● (P)
8key
8key
8key
8key
8key
8key
—
—
●
—
●
—
—
●
—
●
●(Prolo)
● (DSP4ch)
—
—
●
—
—
●
—
●
16 Audio Output
14Wx2
14Wx2
14Wx2, 10Wx2
& 10Wx2
14Wx2
17 Speaker Size & Nbr
160Rx2
160Rx2
160Rx2
& REAR SPK
160Rx2
11 Dolby Surround
12 Dig-Sound Processor
13 Front Surround
14 Cyclone ABX
15 Sub-Bass-System
●
●
● (DSP4ch) ● (DSP4ch)
—
—
—
—
●
●
14Wx2
& 10Wx2
14Wx2
& 10Wx2
160Rx2
160Rx2
& REAR SPK & REAR SPK
18 Comb Filter
19 Dynamic Focus #
20 Scan Velocity Modu
21 Vert Contour Corre
22 Black Level Expand
23 Flesh Tone Correct
24 Dynamic Noise Reduc
25 Picture Preference
26 Digital-Convergence
● (DIG)
●
● (RGB)
—
●
●
●
●
●
● (DIG)
●
● (RGB)
—
●
●
●
●
●
● (DIG)
●
● (RGB)
—
●
●
●
●
●
● (DIG)
●
● (RGB)
—
●
●
●
●
●
● (DIG) ● (3D-Y/C)
●
●
● (RGB)
● (RGB)
—
—
●
●
●
●
●
●
●
●
●
●
27 Horiz Resolution
800
800
800
800
800
800
*
O
T
H
E
R
28 Parental-Ch Lock
29 Channel Label (32ch)
30 3-Language Display
31 Clock/Off-Timer
32 Favorite Channel
33 Extended-Data-Servi
34 Star-Sight-Decoder
●
●
●
●/●
●
●
—
●
●
●
●/●
●
●
—
●
●
●
●/●
●
●
—
●
●
●
●/●
●
●
—
●
●
●
●/●
●
●
—
●
●
●
●/●
●
●
—
*
T
E
R
M
S
35 S-Video In-Term
36 Audio, Video-In/Out
37 Front AV Jack
38 Variable Audio Out
39 2-RF Input
40 Ext Speaker Term
41 PIP Audio Out Jack
42 Center-Ch-Aud-Input
● (1+1)
1+2/1
●
●
*—
●
—
—
● (1+1)
1+2/1
●
●
●
●
—
—
● (1+1)
1+2/1
●
●
●
●
●
—
● (1+1)
1+2/1
●
●
—
●
—
—
● (1+1)
1+2/1
●
●
●
●
—
●
● (1+1)
1+2/1
●
●
●
AC
43 Speaker-Box
*
P
I
C
T
U
R
E
*Cabinet
PARTS SUPPLY (ISO)
—
●
—
—
● (SS-SR94
—
NEW
NEW
NEW
NEW
NEW
NEW
—
—
—
—
—
—
1-3
● (SS-SR94 ● (SS-SR94
5. FRONT AND REAR CONTROL VIEWS
5-1. Front View
POWER indicator
POWER
Press to open the door.
Remote sensor location
POWER button
Behind the door
Fig. 1-1
ANT/VIDEO button*
ADV button
IN-VIDEO 3
S-VIDEO
VIDEO
MENU-ADV
AUDIO
L/MONO
R
DEMO
ANT/VIDEO
CHANNEL
VOLUME
MENU buttom
VIDEO/AUDIO INPUT
jacks
CHANNEL
butttons
DEMO button
S-VIDEO INPUT jack
VOLUME
−/+ buttons
* These buttons have dual functions.
Fig. 1-2
1-4
buttons*
5-2. Rear View
S-VIDEO INPUT jack
TV rear
VARIABLE AUDIO
OUTPUT jacks
A
O
D O
A
O
R
VAR
AUDIO
A
R
VD
I EO
D O
OO
OO
L/MONO
A DO
A P
P A R8
DO
R
D O1
D O2
R
R
PIP
AUDIO
O
O
VIDEO 1 INPUT
jacks
EXTERNAL
SPEAKER
terminals
MAIN
SPEAKER
switch
Fig. 1-3
1-5
VIDEO 2 INPUT
jacks
VIDEO/AUDIO
OUTPUT jacks
5-3. Remote Control View
Transmit indicator
TIMER/Clock*
EDS*
TV/CABLE/VCR switch
EDS
TV
LE
CAB
VCR
TIMER
POWER
POWER
TV/VIDEO RECALL MUTE
RECALL*
TV/VIDEO*
1
2
3
4
5
6
7
8
Channel Number*
MUTE*
0
CHANNEL
VOL
RTN*
9
E N T
100
CH
R T N
VOLUME
S T O P R E W
P LA Y
FF
PIP function*
VCR function*
S W AS
P O U R C E P IP
LO C A TE
P A U S E / S TSILLL O W
T V /V C R
R E C
S T IL L
P IP
C H
AUDio*
PICture*
RESET*
C. CAPT*
SET UP*
. E T U OP P T I O N
P IC . A U D S
OPTION*
R E S E TE X I T
F A V
C . C A PA N
T T 1 /2
C Y C /S B S D S P / S U R
−/+
FAV −/+*
DSP/SUR*
ANT1/2*
SYC/SBS*
EXIT*
To operate buttons inside the cover,
slide the cover down and toward you.
* These functions do not have
duplicate locations on the TV.
They can be controlled only by
the Remote Control.
Fig. 1-4
1-6
CENTER
AMP 2CH
REAR
AMP 2CH
4 -4:DYNAMIC FOCUS
1 :DEF/POWER
2 :MAIN
7A -1:FRONT SURROUND
8 :DIGITAL CONVER
7B -1:DSP 4CH
9 :DOLBY PRO
6A :DIGITAL COMB
3 −3:DPC
FRONT
AMP 2CH
6B :3D Y/C
PIP(HOKURIKU)
7A -2:EDS.CC
7B -2:EDS.CC
to FOCUS
PACK
to CRT
F.B.T
J-BOX
4 -2:SPEAKER
Fig. 1-5
1-7
5 -4:FRONT
FEATURE
1. AUDIO
7A FRONT SURROUND
TP48E50/51/60/61
TP55E50/51
* SPK. TREM. 1pcs
* REAR.CENTER AMP W/O
7B :DSP4CH
5 -5:SVH
TP55E80/81
TP61E80
* SPK TERM. 2pcs
* REAR. AMP W/
* CENTER. AMP W/O
* CENTER INPUT W/
FOCUS PACK
9 :DOLBY PRO
TP48E90
* SPK. TERM. 2pcs
* REAR. CENTER AMP W/
2. COMB FILTER
6A :DIGITAL COMB
5 -1:CRT-D(R)
5 -4:CRT-D(G)
5 -4:CRT-D(B)
:CONV/POW2
TP48E50/51/60/61/90
TP55E50/51
6B :3D Y/C TP61E80
3. TUNER
* TP48E50/51
* TP55E50/51ONLY
1 TUNER
OTHER 2 TUNER
4 -1:A/V
6. PJTV CHASSIS LAYOUT
3
7. CONSTRUCTION OF CHASSIS
9
10
8
1
1
WOOD CABINET
2
LIGHT BOX
3
SPEAKER GRILLE
4
FRONT COVER
5
CRT MOUNTING
6
SHIELD FRONT
7
SHIELD SIDE
8
SCREEN BEZEL
9
SCREEN BRACKET L
10 SCREEN BRACKET S
12
11 CONTROL PANEL
12 BACK BOARD
13 COUPLING R
14 COUPLING G
15 COUPLING B
7
11
16 CHASSIS FRAME MAIN
5
17 CHASSIS FRAME POWER
18 AV TERMINAL BOARD
2
18
13 14 15
16
6
4
3
Fig. 1-6
1-8
17
8. VIDEO SIGNAL FLOW BLOCK DIAGRAM
Basic Circuit Operation
The basic operation of the TG-1 chassis is illustrated in the
block diagrams, figures 1-7 through 1-12. Although these
diagrams focus on the TP48E60, the video and audio signal
flow diagrams can be applied to any TG-1 chassis with
minor modifications.
into the video 1 input jack when the internal test signals are
used.
The selected video signal is output as composite video and
applied to the video output jack, the EDS/CC/RGB SW.,
and the Digital Comb Filter or the 3D - Y/C circuit. After
processing the video signal is sent back to the AV Switcher
as separate luminance (Y) and chrominance (C) signals.
The Y and C signals are then sent to Q501 the Video
Chroma Deflection Processing IC. A sync signal is tapped
off the Y signal and applied to Q501. Q501 processes the
video signal and sends separate R, G, and B signals to the
CRT drives and the CRTs.
Video Signal Flow
Figure 1-7 illustrates the video signal flow through the TG1 chassis. The Antenna 1 (ANT 1) and Antenna 2 (ANT
2) inputs allow two separate RF signals to be connected to
the RF switcher. When the switch, which is controlled by
the microcomputer, QA01, is in the up position the ANT 1
signal is connected to the HY01 PIP Tuner/IF and the H001
Main Tuner. Moving the switch down connects the ANT
2 signal to the H001 Tuner. Due to the RF Switch the ANT
2 signal can’t be used as the PIP source, but when ANT 2
is selected the ANT 1 signal is available at RF OUT. The
PIP Tuner/IF produces a composite video (CV) signal and
sends it to the AV Switcher, QV01. An IF signal produced
by the Main Tuner is sent to H002, which produces a
composite video signal and sends it to the AV Switcher.
If the PIP feature is selected, composite video from AV
Switcher is sent to the PIP circuit, ZY01. After processing,
the PIP signal is sent to Q501 as R, G, B, and YS where it
is mixed with the main video.
On screen display (OSD) R, G, and B signals produced by
the Microcomputer, QA01, are mixed with the Extended
Data Service (EDS) and Closed Caption (CC) data in
UM01. These new signals are applied to an OR gate,
QB91, and combined with the convergence signals from
the digital convergence circuit. The convergence signals
can be either the customer convergence cross hairs, or the
service cross hatch pattern. All of these signals are sent to
Q501 where they are mixed with the main video signal.
Three video inputs, video 1 through 3, are applied to the AV
Switcher. The video 1 input can be composite video, Y/C
video, or the test signal from QA01. Video 2 is composite
video only, and video 3 is either composite video or Y/C
video. A mechanical switch on the video 1 input defaults
to the test signal, so a video connector must not be plugged
1-9
TEST
VIDEO 1
9
12
CV/Y
C
14
VIDEO 2
VIDEO 3
1-10
Figure 1-7 Video Signal Flow Block Diagram
ANT 1
QV01
CV
CV/Y
AV
SWITCHING
16
C
18
RF
SWITCH
3
9
HY01 PIP
TUNER/IF 15
CV
28
C
H001
MAIN
TUNER
RF
OUT
ANT 2
2
CONTROL
FROM
QA01
34
13
Y
IF
H002
IF/MTS
A. PRO
36
17
7
CV
38
CV
TEST SIGNAL
TO VIDEO 1
30
6
32
42
Y
C
2
4
CV
DIGITAL
COMB
FILTER
OR, 3D - Y/C
QA01
9
YS
R
23
24
E032Z
GREEN CRT
DRIVE
GRN CRT
E033Z
BLUE CRT
DRIVE
BLUE CRT
41
Q501
MAIN VIDEO
INPUT
SYNC
CV TO VIDEO
OUT JACK
22
15
Q204
EQ
OSD
DATA
42
RED CRT
Y
Q202
7
MICRO
COMPUTER
43
C
Q503
B
G
R
E031Z
RED CRT
DRIVE
G
B
18
19
20
21
CV
UM01
EDS/CC
RGB SW.
YS
6
R
1
G
5
2
B
8
YS
R
G
B
ZY01
PIP
5
9
YS
32
4
R
35
5
G
34
6
B
33
PIP VIDEO
INPUT
FROM
DIGITAL
CONV.
10
4
13
1
YS
3
2
12
1
VIDEO CHROMA
DEFLECTION
PROCESSING
OR
QB91
11
6
8
R
G
B
36
39
38
37
OSD, EDS, CC, &
CONVERGENCE
VIDEO INPUT
9. AUDIO SIGNAL FLOW BLOCK DIAGRAM
Audio Signal Flow
jumper is removed so a center signal can be switched in to
replace the main left and right signals. The amplified left
and right audio signals are applied to the internal/external
speaker switch and routed to the desired speakers.
Audio signals are applied to the AV Switcher from the
three video jacks, H002, and the PIP Tuner, as shown in
Figure 1-8. Like the video signal, there must not be a
connector in the video 1 jack for the audio test signal to be
applied to the AV Switcher. In the TP48E90, PIP audio is
applied to the PIP output jack. The main audio signals are
applied to the audio output jacks and to the Front Surround
circuit, the DSP/Dolby circuit, or the Dolby Pro Logic
circuit. Afterprocessing, the left and right audio signals
are applied to the audio processor in H002 where the
volume, balance, treble, and bass are controlled. Next, the
audio signals are amplified by QS101 and applied to the
variable output jacks, and Q601. If the sub bass system
(SBS) is selected, a signal is mixed with the left and right
signals just before Q601 to increase the signals bass
response. In TP55E80/81 and TP61E80 models, the
Sets equipped with Dolby or Dolby Pro Logic have a
surround audio signal that is sent to the audio processor in
H002 from the Dolby circuit. The surround signal is then
sent to the rear amplifier, Q641, amplified, and applied to
the rear speakers. In the TP48E90 the surround signal is
routed through an amplifier in Q690 before it is applied to
Q641. Also, the TP48E90 is equipped with Dolby Pro
Logic, and has a center channel. The center channel is
amplified by the Center Amplifier, Q621, and applied to
the front speakers through the internal/external speaker
switch.
8
L
TEST SIGNAL
FROM QA01
R
VIDEO 1
QV01
11
13
29
MONO AUDIO
FROM HY01
PIP TUNER
AV
SWITCHING
31
L
R
H002
IF/MTS/A. PRO
23
SURROUND
TP48E90
TP55E80/81
TP61E80
26
24
R
22
17
16
18
L
R
VIDEO 3
TO PIP OUT JACK
(TP48E90 ONLY)
6
37
IF
FROM H001
MAIN TUNER
L
R
17
1
VIDEO 2
R
15
2
5
L
9
QV14
35
L
L
R
3
R
TO AUDIO
OUT JACK
QS04
2
L
6
L
FRONT SURROUND,
DSP/DOLBY,
OR
DOLBY PRO LOGIC
R
5
SURROUND OUT
11
2
12
4
7
CENTER OUT
10
Q621
CENTER AMP
TP48E90 ONLY
SBS (SUB BASS SYSTEM)
TO &FROM CENTER
INPUT SWITCH & JACK
TP55E80/81 & TP61E80
ONLY
5
7
+
5
7
2
L INT/EXT
11 SWITCH
L
3
R
1
QS101
+
R TO VARIABLE AUDIO
OUT JACK
L
1
Q601
R
L
FRONT OR
CENTER
SPEAKERS
R
EXTERNAL
2
12
4
7
3
Q690
TP48E90
ONLY
Q641
REAR AMP
Figure 1-8 Audio Signal Flow Block Diagram
1-11
REAR
SPEAKERS
10.
POWER SUPPLY AND PROTECTION BLOCK DIAGRAM
The Control/Protection circuit, Z801, has two functions.
The first is to regulate the Main Switch Mode Supply, and
the second is to monitor over current, over voltage, and
under voltage sensors throughout the set. If any one of
these sensors activates the protection circuit, Z801 turns
off the switch powering the two switch mode supplies thus
turning off the set. If this occurs, a red LED on the front
panel flashes at half second intervals, and the set must be
unplugged to reset Z801.
The E model PTVs actually have three separate power
supplies as shown in Figure 1-9. These supplies consist of
the Standby Supply, the Main Switch Mode Supply, and
the Sub Switch Mode Supply. The Standby Supply provides
the 5 VDC needed to run the microcomputer and the
customer interface controls, such as the key pad and the IR
receiver. When the set is turned on, the switch closes to
activate the two switch mode supplies and provide the
numerous DC voltages needed to operate the set.
STANDBY
REGULATOR
TO MICROCOMPUTER
RESET
+30VDC
SWITCH
MODE
(SUB)
SWITCH
120VAC
+5VDC
FEEDBACK
POWER
ON/OFF FROM
MICROCOMPUTER
16
13
14
X-RAY SENSING
+12VDC
+38VDC
+125VDC
1
OVERCURRENT,
OVERVOLTAGE, &
UNDER VOLTAGE
SENSING
Figure 1-9 Power Supply/Protection Block Diagram
1-12
REG
+15VDC
REG
-9VDC
-15VDC
3
Z801
CONTROL/PROTECTION
+5VDC
+15VDC
SWITCH
MODE
(MAIN)
POWER
OFF
REG
11. HORIZONTAL AND VERTICAL DEFLECTION
Vertical drive (VD) is applied to the DPC circuit, U421, to
correct any distortions before it’s sent to the Vertical Drive
circuit, Q301. Then the vertical drive circuit supplies the
signals required by the yokes for deflection.
Deflection circuitry in the E model PTV’s is rather straight
forward as show in Figure 1-10. The horizontal pulse from
Q501 drives the horizontal drive circuitry, which in turn
drives the Horizontal Yokes and the Flyback Transformer,
T461. Numerous low voltage DC supplies are produced by
the Flyback, as well as the high voltages for the anode,
focus, and screen drives. To prevent excessive high
voltages, a sample X-Ray protection voltage is monitored
by the over voltage protection circuits.
AC TO HEATERS
+23VDC TO X-RAY
PROTECT
+12VDC
To enhance horizontal transitions between dark and light
areas of the picture, a Velocity Scan Modulation (VSM)
signal is produced by Q501. This signal is sent to the SVM
circuit, E036Z, which in turn drives the SVM coils on the
CRTs.
T461
9
7
+35VDC
2
1
31
48
R
G
B
8
TO ABL
CIRCUIT
4
FOCUS &
SCREEN DRIVE
TO CRTs
HORIZ
DRIVE
HORIZ
DRIVE
23
VD
FOCUS
BLOCK
30.7KV
TO CRT
ANODES
3
+125VDC FROM
MAIN POWER
VIDEO
CHROMA
DEFLECTION
PROCESSING
2
FLYBACK
TRANSFORMER
5
+200VDC
H-OUT
R
G
B
6
-27VDC
Q501
HV
DIST
BLOCK
HV
TO HORIZ
YOKES
U421
DPC
CIRCUIT
Q301
4
VERTICAL
DRIVE
6
2
TO VERT
YOKES
VSM
EO36Z
2
SVM
CIRCUIT
1
TO SVM
COILS
Figure 1-10 Horizontal and Vertical Deflection Block Diagram
1-13
12. I2C Communications
REG
The TG-1 chassis uses I2C data communications to
control all customer features and most of the service
adjustments that where previously done with discrete
devices, refer to Figure 1-11. All communications
are controlled by the Microcomputer, QA01 through
serial data lines (SDA) and serial clock lines (SCL).
Memory settings for customer controls and service
adjustments (except convergence data) are stored in
the E2PROM Memory, QA02, and communicated
to QA01 by the SCL0 and SDA0 lines. Data and
clock lines SDA1 and SCL1 communicate with
most of the circuits in the set. However, there are
three plug in circuits where the data and clock
signals are buffered by QB90 to provide isolation.
RCUT
GCUT
BCUT
RDRV
BDRV
CNTX
BRTC
COLC
TNTC
SCOL
SCNT
HPOS
VPOS
HIT
GMPS
VLIN
VSC
VPS
VCP
WID
TRAP
HCP
VFC
STRH
All customer functions and most services
adjustments are implemented through the Key Pad
and the Remote Sensor. The RMT OUT signal on
the microcomputer drives the IR Transmitter on the
front panel, but it’s only used in the manufacturing
process. Figure 1-12 shows the Service Registers
and their default values used for making adjustments
in the set.
KEY B
KEY A
QA01
38
MICROCOMPUTER
37
SDA1
40
40
40
40
40
7F
80
50
40
15
15
16
00
D1
00
12
08
15
03
25
10
02
0F
82
H001
TUNER
H002
IF/MTS/A.PRO
27
28
21
20
9
10
25
24
HY01
TUNER/IF
4
3
44
43
SCL1
COMB FILTER
OR
3D-Y/C
3
RED CUTOFF
GREEN CUTOFF
BLUE CUTOFF
RED DRIVE
BLUE DRIVE
SUB-CONTRAST MAX
SUB-BRIGHT CENTER
SUB-COLOR CENTER
SUB-TINT CENTER
SAP-COLOR
SUB-CONTRAST
HORIZ. POSITION
VERTICAL POSITION
VERTICAL HEIGHT
GMPS
VERTICAL LINEARITY
A-S CORRECTION
VERTICAL SHIFT
V-COMPENSATION
PICTURE WIDTH
TRAPEZIUM
H-COMPENSATION
V-F CORRECTION
HORIZ. START POSITION
Figure 1-12 Service Register Default Values
IC501
V/C/D
PROCESSING
35
17
TO IR
LED
TRANS
PRESET
REMOTE
SENSOR
KEY
PAD
18
ADJUSTMENT
1
2
QAV01
AV
SWITCHING
U421
DPC CIRCUIT
Q701
CONV.
PROCESSOR
F. SURR.,
DSP/DOLBY,
D. PRO LOGIC
ZY01
PIP
CIRCUIT
UM01
EDS/CC
RGB SW.
RMT OUT
SCL0
11
12
6
5
QA02
EEPROM
MEMORY
SDA0
14
3
15
SDA2
5
2
SCL2
6
QB90
Figure 1-11 I2C Communication Block Diagram
1-14
14
13
14
13
13. Digital Convergence
The TG-1 model PTV’s are equipped with a new digital
convergence circuit shown in Figure 1-13. This circuit
allows servicers to set the convergence with the remote
control. Q701, the Digital Convergence Processor aligns
the convergence from data received from the remote, and
saves the settings in the E2PROM, Q713. The digital
convergence signals are converted to analog by the D/A
Converters Q703, Q704, and Q705. Then they are amplified
by the pre amps (Q715, Q717, & Q719) and power amps
(Q751 & Q751) before being applied to the convergence
yokes. The Power Amps Q752 and Q751 dissipate allot of
heat because of their current draw, so the supplies to these
amps have a number of sensors for over current conditions.
Most of the convergence circuit is on a shielded board, but
the power amps are easily accessible for service.
Q713
EEPROM
Q752
CLK
6
5
45
46
DATA
86
Q701
FROM
QAO1
CLK
DATA
44
89
97
HD
FROM
IC501
RV
6
GH
7
GV
6
BH
7
90
96
31
7
87
43
DIGITAL
CONVERGENCE
PROCESSOR
RH
BV
6
Q703
D/A
CONV.
20
Q704
D/A
CONV.
20
Q705
D/A
CONV.
20
1
3
Q715
3
Q717
1
3
14
11
6
9
15
18
14
11
6
9
RH
GH
BH
TO
CONV.
YOKES
1
7
5
5
18
7
5
1
1
15
Q719
RV
7
1
GV
32
VD
FROM
Q301
Q751
Figure 1-13 Convergence Block Diagram
1-15
BV
LAB 1
BASIC OPERATION AND UNIT UNDERSTANDING
As a servicer, it is important now, more than ever, to fully understand the operation and functions of
a television set before proceeding with a repair. This is because many of the problems encountered by
a customer today can be caused by an incorrect menu selection or improper setup.
Therefore, the purpose of this lab is to familiarize you with menus and features of the television from
the customer’s point of view.
SECTION ONE
BASIC OPERATION
1. Verify that the unit is connected to an AC supply, and that a signal is connected to the ANT 1
input. While verifying signal connections, take time to examine all of the inputs on the rear and
front (behind door) of the unit.
2. Turn on the set with the remote control and tune to an active channel. Refer to page 9 of the
service manual provided and familiarize yourself with all of the keys on the remote paying,
particular attention to the following keys:
o
o
o
EDS
TIMER
PIP Functions
Open the bottom door on the remote control by sliding it down. Try each key starting with the upper
row. Each of these buttons brings up another menu and/or sub-menus.
3. In the Picture Menu, What is Color Temperature?
____________________________________________________________________________
____________________________________________________________________________
4. In the Audio Menu, Where can the speakers be turned off by the user?
____________________________________________________________________________
____________________________________________________________________________
5. In the Setup Menu, What is Favorite Channel?, What is Channel Lock?
____________________________________________________________________________
____________________________________________________________________________
1-16
6. Refer to page 16 of the Service Manual and perform the User Convergence Adjustments. How
is this different from previous Toshiba PJTVs?
____________________________________________________________________________
____________________________________________________________________________
7. In the Option Menu, How many different languages are there? What are they used for? What is
Channel Label Used for?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
NOTES:
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
SECTION TWO
DISASSEMBLY & SERVICE POSITION
Follow the procedure listed below to gain access to the tubes and circuit boards.
1. Remove the speaker grill by holding the sides and pulling straight out.
2. Take out the four screws holding the plastic shield in place. Then remove the shield.
3. Remove the control wires from the holder on the metal shield in front of the CRTs.
4. Remove the 4 screws holding the metal shield in place. The shield is notched, so slide it to the
right then down to remove it.
5. Remove the two screws holding the front control panel. Then release the tabs on either side and
let it hang down out of the way.
6. Remove the 4 screws holding the bottom of the screen. Then lift up on the top of the screen and
pull it away from the cabinet.
1-17
7. Remove the 5 screws holding the back panel. Then remove the back panel.
8. Reattach the control panel to the light box.
9. Remove the six screws on the front of the light box.
10. Remove the three screws on the back of the cabinet.
11. Remove the one screw holding the back of the light box to the cabinet.
12. From the front of the set, lift the light box up just a little, and pull it towards you.
13. Pull the light box all the way out of the cabinet and turn it on its side.
CAUTION: the light box weighs about 85 pounds, so get help if you need it.
SECTION THREE
IDENTIFICATION
1. Identify each of the board assemblies and note their locations. Use Figure 1-5 to help you
identify the various boards.
o
o
o
o
o
o
o
Convergence/Output/Power Board
Deflection/Power Board
Main PCB
Front Surround Board
Digital Comb Filter Board
PIP Board
EDS/CC Board
2. Is there a convergence board in this unit?
If so, where?
____________________________________________________________________________
____________________________________________________________________________
3. How does this convergence setup differ from previous models?
____________________________________________________________________________
____________________________________________________________________________
4. Examine the Flyback and HV lead assemblies. What is different about this area from earlier
models?
____________________________________________________________________________
____________________________________________________________________________
1-18
5. Is it possible for one technician to perform a service call on this type of unit?
____________________________________________________________________________
____________________________________________________________________________
6. Put the lightbox in the cabinet, but don't screw it in. Then replace the screen and control panel.
Use a few screws to hold the screen and control panel in place.
SUMMARY
In this lab, the operation and function of the unit was determined, and the unit was set up for service
on the bench. Common user type problems in addition to overall serviceability was also discussed.
END OF LAB 1
1-19
LAB 2
TEST SIGNALS, SELF DIAGNOSTICS, & SERVICE REGISTERS
OBJECTIVES: After completing this lab you will be able to:
1. Enter and exit the set’s internal video and audio test signals.
2. Use the test signals for troubleshooting.
3. Use the set’s self diagnostic feature.
4. Make adjustments in the set with the service registers via the remote control.
SECTION ONE
VIDEO TEST SIGNALS
1. Verify that the unit is connected to an AC supply, and that a signal is connected to the ANT 1
input.
2. Enter the service mode by pressing mute on the remote. Press and hold mute a second time
while pressing menu on the control panel. An S appears in the upper right corner of the screen
indicating that the set is in the service mode. Press menu and the RCUT register appears in the
upper left corner of the screen.
3. Push the TV/VIDEO button on the remote once to enter the internal test pattern mode. The
screen should be red.
4. Slowly cycle through the test signals with the TV/VIDEO button until the white cross hairs on
a black background appear. (If the TV/VIDEO button is pushed in rapid succession, the set will
jump out of the test signal mode to one of the inputs - ANT 1, VIDEO 1, VIDEO 2, or VIDEO
3. The set is still in the service mode, so if this occurs, push the menu button then the TV/
VIDEO button to get back into the test signal mode.)
5. Plug a video cable into the VIDEO 1 input jack (make sure the other end of the cable is not
plugged into a video source)
6. What happened to the cross hairs?
____________________________________________________________________________
____________________________________________________________________________
7. If something did happen to the cross hairs, why did it happen?
____________________________________________________________________________
____________________________________________________________________________
1-20
8. Is there video on the screen?
____________________________________________________________________________
____________________________________________________________________________
9. If there is video on the screen, where does it come from?
____________________________________________________________________________
____________________________________________________________________________
10. Unplug the video cable.
SECTION TWO
AUDIO TEST SIGNALS
1. Push the 8 button on the remote to activate the audio test signal. (NOTE: The internal test
pattern mode must be activated for this feature to work.)
2. Push the mute button twice. Now you can control the volume of the signal.
3. Select AUD on the remote control.
4. Select BALANCE and adjust it from left to right with the + and - buttons.
5. Select SPEAKERS and turn them off then on. (NOTE: The speakers are turned off at Q601,
refer to Figure 1-8, while the volume, bass, treble, and balance are controlled in H002. This
means you can troubleshoot most of the audio system with the speakers off.)
6. Plug an audio cable into the left AUDIO 1 input jack (make sure the other end of the cable is
not plugged into an audio source)
7. What happened to audio?
____________________________________________________________________________
____________________________________________________________________________
8. If something did happen to the audio, why did it happen?
____________________________________________________________________________
____________________________________________________________________________
9. Push the 8 button to turn off the audio test signal.
10. Cycle the video test signals back to the ANT 1 signal with the TV/VIDEO button.
1-21
SECTION THREE
SELF DIAGNOSTICS
1. Push the 9 button to activate the self diagnostic feature.
2. What does POWER indicate?
____________________________________________________________________________
____________________________________________________________________________
3. What does BUS LINE indicate?
____________________________________________________________________________
____________________________________________________________________________
4. What does BUS CONT indicate?
____________________________________________________________________________
____________________________________________________________________________
5. What does BLOCK indicate?
____________________________________________________________________________
____________________________________________________________________________
6. Push the EXIT button to exit the self diagnostic feature.
7. Select the VIDEO 1 input with the TV/VIDEO button. (Make sure there is no signal applied to
VIDEO 1)
8. Push MENU on the control panel to display the registers.
9. Push 9 to activate the self diagnostic feature.
10. Is the display different from the previous display. ______
11. If it is, explain why.
____________________________________________________________________________
____________________________________________________________________________
12. Push the EXIT button to exit the self diagnostic feature.
13. Push MENU on the control panel to display the registers.
1-22
SECTION FOUR
SERVICE REGISTERS
NOTE: In each of the following exercises write down the register’s value before adjusting it. Then
restore the register to its original value before proceeding to the next exercise.
1. Enter the internal test pattern mode and select the test signal that has a white window in the
upper center of a black background as shown below.
2. Increase the RCUT register value and describe its effect on the picture.
RCUT______
____________________________________________________________________________
____________________________________________________________________________
3. Change the test signal to the white on black cross hatch pattern as shown below.
4. Select the HPOS register and vary its value between 00 and 1F. Describe its effect on the
picture. What happens if you increase the register to 20?
HPOS______
____________________________________________________________________________
____________________________________________________________________________
5. Select the VPOS register and vary its value between 00 and 07. Describe its effect on the
picture. What happens if you increase the register to 08?
VPOS______
____________________________________________________________________________
____________________________________________________________________________
1-23
6. Select the HIT register and vary its value 5 steps above and below the recorded value.
Describe its effect on the picture.
HIT______
___________________________________________________________________________
____________________________________________________________________________
7. Select the VLIN register and vary its value 8 steps above and below the recorded value.
Describe its effect on the picture.
VLIN______
___________________________________________________________________________
____________________________________________________________________________
8. Select the WID register and vary its value 8 steps above and below the recorded value.
Describe its effect on the picture.
WID______
___________________________________________________________________________
____________________________________________________________________________
9. Select the STRH register and vary its value 8 steps above and below the recorded value.
Describe its effect on the picture.
STRH______
___________________________________________________________________________
____________________________________________________________________________
SUMMARY
Now that you have completed Lab 2, you should be able to use the internal video and audio test
signals, the self diagnostic feature, and the service registers for making adjustments.
END OF LAB 2
1-24
SECTION II
TUNER, IF/MTS/S.PRO MODULE
2-1
1. CIRCUIT BLOCK
H002 - IF/MTS/A.PRO Module MVUS34S
EL466L
H001
Main Tuner
VIF/SIF
Circuit
SAW
Filter
SIF
output
Sound
Multiplex
Circuit
A.PRO Circuit
RF AGC
C-IN
R-IN L-IN
TP12
Video output
TV
R-OUT
To A/V switch circuit
AFT output
TV
L-OUT
R-OUT
C-OUT
L-OUT (L+R)
-OUT
Fig. 2-1 Block diagram
1-1. Outline
(1) RF signals sent from an antenna are converted into
intermediate frequency band signals (video: 45.75 MHz,
audio: 41.25 MHz) in the tuner. (Hereafter, these signals
are called IF signals.)
(2) The IF signals are band-limited in passing through a
SAW filter.
(3) The IF signals band-limited are detected in the VIF
circuit to develop video and AFT signals.
(4) The band-limited IF signals are detected in the SIF
circuit and the detected output is demodulated by the
audio multiplexer, developing R and L channel outputs.
These outputs are fed to the A/V switch circuit.
(5) A sound processor (S.PRO.) is provided.
(5) VIF/SIF circuit uses PLL sync detection system to
improve performances shown below:
• Telop buzz in video over modulation
• DP, DG characteristics (video high-fidelity
reproduction)
• Cross color characteristic (coloring phenomenon at
color less high frequency signal objects)
(6) HIC SBX1637A-22 is used in the audio multiplexer
circuit to minimize the size with increased performance.
(7) As a sound control processor, TA1217N is used. I2Cbus data control the DAC inside the IC to perform
switching of the audio multiplexer modes.
1-2. Major Features
(1) The VIF/SIF circuit is fabricated into a small module
by using chip parts considerably.
(2) As the tuner, EL466L that which contains an integrated
PLL circuit is employed.
(3) Wide band double SAW filter F1802R used.
(4) FS (frequency synthesizer) type channel selection system
employed.
2-2
1-3. Audio Multiplex Demodulation Circuit
The sound multiplex composite signal FM-detected in the
PIF circuit enters pin 12 of HIC (hybrid IC) in passing
through the separation adjustment VR RV2 and amplified.
After the amplification, the signal is split into two: one enters
a de-emphasis circuit, and only the main signal with the L-R
signal and a SAP signal removed enters the matrix circuit. At
the same time, the other passes through various filters and
trap circuits, and the L-R signal is AM-demodulated, and the
SAP is FM-demodulated.
Then, both are fed to the matrix circuit. At the same time,
each of the stereo pilot signal fH and the SAP pilot signal 5fH
is also demodulated to obtain an identification voltage. With
the identification voltage thus obtained and the user control
voltage are used to control the matrix.
The audio signals obtained by demodulating the sound
multiplex signal develop at pin 10 and 11 of HIC and develop
the terminals of 12 and 14 of the module.
MVUS34S
MPX
Out
TV
TV
DAC-out1
R-Out (SURR ON/OFF) L-Out
9
Monitor the input
pin for multiplex
sound IC
11
10
12
Stereo 0V
SAP 0V
Other 5V
Other 5V
13
14
DAC-out2
(RFSW)
15
OFF 0V
RF1
0V
ON
RF2
9V
9V
TV waveform detection TV waveform detection
output (R)
output (L)
To AV select circuit
Fig. 2-2 Block diagram of MVUS34S
Table 2-1 Matrix for broadcasting conditions and
reception mode
Note:
Of the mode selection voltages, switching voltages for STE,
SAP, MONO do not output outside the module.
They are used inside the module to control the BUS.
Output
OSD display
Broad- Switching
12 pin 14 pin
casted
mode
Stereo SAP
(R)
(L)
Stereo STE
SAP
MONO
Mono STE
SAP
MONO
R
R
L+R
L+R
L+R
L+R
L
L
L+R
L+R
L+R
L+R
Y
Y
Y
N
N
N
N
N
N
N
N
N
Stereo STE
+
SAP
SAP MONO
R
SAP
L+R
L
SAP
L+R
Y
Y
Y
Y
Y
Y
Mono
+
SAP
L+R
SAP
L+R
L+R
SAP
L+R
N
N
N
Y
Y
Y
STE
SAP
MONO
2-3
1-4. A.PRO Section (Audio Processor)
The S.PRO section has following functions.
(1) Woofer processing (L+R output)
(2) High band, low band, balance control
(3) Sound volume control, cyclone level control
(4) Cyclone ON/OFF
All these processing are carried out according to the BUS
signals sent from a microcomputer.
Fig. 2-3 shows a block diagram of the A.PRO IC.
TA1217N
27 29 22 32 36
1
Lin
30
9
8
34
28
26 L out
BALANCE
Rin
30
Cin
2
TONE CONTROL
25 R out
Center
LEVEL
VOLUME
18 C out
10 W out
Win
3
Woofer
LEVEL
LPF
17
16
I/O
15
14
13
SDA 20
D/A
CONV
2
I C
SCL 21
4
16
17
18
R-in
C-in
L-in
5
19
6
20
7
21
22
23
SCL1 SDA1 W-out C-out
31
24
L-out
24
23
25
22
19
26
27
R-out
9V
From From
A/V Dolby
From
A/V
to Q601 to Q641 to Q601
to Q601
SBS
Via QS101
Fig. 2-3 A.PRO block diagram
2-4
12
SAP Ident.
11
STE Ident.
Configuration of the audio circuit and signal flow are given
in Fig. 2-4
A/V PCB
VIF+MTS+S.PRO
MODULE
R 12
L 14
R
EQ
ER
L
VIDEO3
(FRONTINPUT)
R
R
6 R
5 L
11 L
13 R
8 L
9 R
VIDEO1
VIDEO2
FOR PIP
IF MODULE
QV01
L
L
AF
AG
15 L
17 R
From
Main
Tuner
VIDEO1
L 29
FromPIP
Tuner
R 31
PIP
OUTPUT
L 2
L
R 1
R
EN
AUDIO
PIP OUT
TP48E90 ONLY
(AUDIO)
VIDEO
OUTPUT
TERMINAL
VIDEO2
VIDEO3
ROUT 26
AS
R 35
L 37
AR
DSP
CIRCUIT
R L
VARIABLE
AUDIOOUTPUT
TERMINAL
Q601
VIF+MTS+A.PRO
MODULE
AI
AJ
Fig. 2-4
2-5
16 R
18 L
L OUT 24
WOUT 22
+
+
R
L
2
11
5
7
R
L
2. PIP TUNER
Lable
TUNER
SECTION
SAW
FILTER
VIF/SIF
CIRCUIT
Name
Lot No.
RF AGC
VIDEO
AUDIO
AFT
OUTPUT OUTPUT OUTPUT
1
Fig. 2-5
2-1. Outline
The PIP tuner (EL922L) consists of a tuner and an IF block
integrated into one unit. The tuner receives RF signals
induced on an antenna and develops an AFT output, video
output, and audio output.
The tuner has receive channels of 181 as in the tuner for the
main screen and it is also controlled through the I2C-bus.
As the IC for the IF, a PLL complete sync detection plus
audio inter carrier system are employed.
15
Terminal No.
Name
1
2
NC
32V
3
S-CLOCK
4
S-DATA
5
NC
6
ADDRESS
7
8
5V
RF AGC
9
9V
10
AUDIO
11
GND
12
13
AFT
NC
14
GND
15
VIDEO
Fig. 2-6 Tuner terminal layout
2-6
SECTION III
CHANNEL SELECTION CIRCUIT
3-1
1. OUTLINE OF CHANNEL SELECTION
CIRCUIT SYSTEM
• Setting of memory values for video parameters
such as white balance (RGB cutoff, GB drive) and
gcorrection, etc.
• Setting of video parameters of video modes
(Standard, Movie, Memory)
The channel selection circuit in the N5SS chassis employs a
bus system which performs central control by connecting
a channel selection microcomputer to a control IC in each
circuit block through control lines called a bus. This bus
system herin referred to as the I2C bus system (two line bus)
is licensed from and was developed by Philips.
(3) CONTROL OF A/V SWITCH IC (QV01 Toshiba
TA1218N)
• Preforms source switching for main screen and
sub screen
• Performs source switching for TV and up to three
video inputs
Integrated circuits controlled by the I2C bus system are :
QN06 for audio signal processing, Q501 for V/C/D signal
processing , QV01 for A/V switching, QA02 for non
volatile memory, main and sub U/V tuners (H001, HY01),
Q302 for deflection distortion correction, QY04 for PIP
signal processing, QM01 for DSP, and Q701 for closed
caption control.
(4) CONTROL OF NON-VOLATILE MEMORY IC
(QA02 Microchip 24LC08BI/P)
• Memorizes data for video and audio signal
adjustment values, volume and woofer adjustment
values, external input status, etc.
• Memorizes adjustment data for white balance
(RGB cutoff, GB drive), sub-brightness, sub color,
sub tint, etc.
• Memorizes deflection distortion correction value
data adjusted for each unit.
Differences from the previous N5SS chassis include;
1. On-screen display generation now originates within
ICA01. A separate IC is no longer used.
2. The microcomputer does not perform the closed
caption function, but instead controls a separate IC
for this purpose.
3. The system uses two sperate channels of I2C bus. One
of these is dedicated for communication with the
non-volatile memory.
(5) CONTROL OF U/V TUNER UNIT (H001 Matsushita
EL466L, HY01 Toshiba EL922L)
• A desired channel can be tuned by transferring a
channel selection frequency data (divided ratio
data) to the I2C bus type frequency synthesizer
equipped in the tuner, and by setting a band
switch which selects the UHF or VHF band.
2. OPERATION OF CHANNEL
SELECTION CIRCUIT
An 8 bit, Toshiba microcomputer (series TLCS-870) is
used within the television as ICA01.
Part number
TMP87CS38N-3152 or similar is employed.
With this microcomputer, each IC and circuit shown below
are controlled.
(6) CONTROL OF DEFLECTION DISTORTION
CORRECTION IC (Q302 Toshiba TA8859P)
• Sets adjustment memory value for vertical
amplitude, linearity, horizontal amplitude,
parabola, corner, trapezoid distortion.
(1) CONTROL OF AUDIO SIGNAL PROCESS IC (QN06
Toshiba TA1217N)
• Adjustments for volume, treble, bass and balance
• Selection between surround mode and DSP mode,
and level adjustment
• Level adjustment of BAZOOKA (Sub-Bass)
system
• Audio muting during channel selection or no signal
reception.
(7) CONTROL OF PIP SIGNAL PROCESS IC (QY04
Toshiba TC9083F)
• Controls ON/OFF and position shift of PIP.
(8) CONTROL OF DIGITAL SOUND PROCESSOR IC
(QM04 Yamaha YSS238-D)
• Performs mode switching of DSP.
(9) CONTROL OF CLOSED CAPTION/EDS (QM01
Motorola XC144144P)
• Controls Closed Caption/EDS.
(2) CONTROL OF VIDEO/CHROMA/DEF SIGNAL
PROCESS IC (Q501 Toshiba TA1222N)
• Adjustments for uni-color, brightness, tint, color
gain, sharpness and PIP uni-color
• Setting of adjustment memory values for subbrightness, sub-color and sub-tint, etc.
3-2
3. MICROCOMPUTER
one chip.
IIC device controls through I2C bus. (Timing chart : See fig.
3-1)
• Pin 8, (LED) is used to source current and is an output
only.
• For clock oscillation, an 8MHz ceramic oscillator is
used.
• I2C has two channels. One is for EEPROM only.
• A Self diagnosis function which utilizes the ACK
function of I2C is employed
• Function indication is added to service mode.
• Operation by remote control is possible, and controls
and adjustments can be made with no physical contact
is possible. (Bus connector in the conventional bus
chassis is deleted.)
• Substantial self diagnosis function
(1) B/W composite video signal generating function
(inside micon, green crossbar added)
(2) Generating function of audio signal equivalent
to 1kHz (inside micon)
(3) Detecting function of power protection circuit
operation
(4) Detecting function of abnormality in I2C bus
line
(5) Functions of LED blink indication and OSD
indication
(6) Block diagnosis function which uses new VCD
and AV SW
The main Microcomputer TMP87CS38N-3152 has 60k
byte of ROM capacity and is equipped with an internal OSD
function.
The specification is as follow.
• Type name : TMP87CS38N-3152
• ROM : 60k byte
• RAM : 2k byte
• Processing speed : 0.5m s (at 8MHz with Shortest
command)
• Package : 42 pin shrink DIP
• I2C-BUS : two channels
• PWM : 14 bit x 1, 7 bit x 9
• ADC : 8 bit x 6 (Successive comparison system,
Conversion time 20ms)
• OSD
Character kinds : 256
Character display : 24 characters x 12 lines
Character dot
: 14 x 18 dots
Character size
: 3 kinds (Selected by line)
Character color : 8 colors (Selected by character)
Display position : Horizontal 128 steps, Vertical
256 steps
This microcomputer performs the functions of an Analog to
Digital converter, reception of U/V TV and OSD display in
SDA
SCL
1-7
Start
condition
Address
8
9
R/W
Ack
1-7
8
Data
Approx.180m S
9
Ack
8
1-7
DATA
9
Ack
Some device may have no data,
or may have data with several
bytes continuing.
Fig. 3-1
3-3
Stop
condition
4. MICROCOMPUTER TERMINAL FUNCTION
TMP87CS38N3152 (QA01)
42
VDD
41
ACP
P32
40
NC
P42 (PWM2)
P57
39
GND
P43 (PWM3)
SDA0
38
SDA1
VDD
GND
1
BAL
2
I
P40 (PWM0)
P57
REM OUT
3
O
P41 (PWM1)
MUTE
4
O
SP MUTE
5
O
GND
I
IO
IICBUS
NC
6
O
P44 (PWM4)
SCL0
O
37
SCL1
POWER
7
O
P45 (PWM5)
(TC3)P31
I
36
SYNC AV1
LED
8
O
P46 (PWM6)
(RXIN)P30
I
35
RMT IN
NC
9
O
P47 (PWM7)
P20
I
34
SW IN
NC
10
I
P50 (PWM8/TC2)
RESET
I
33
RESET
SCL0
11
O
P51 (SCL1)
XOUT
O
32
XOUT
SDA0
12
IO
P52 (SDA1)
XIN
I
31
XIN
SYNC VCD
13
I
P53 (AINO/TC1)
TEST
I
30
TEST
NC
14
I
P54 (AIN1)
0SC2
O
29
0SC1
AFT2
15
I
P55 (AIN2)
0SC1
I
28
0SC2
AFT1
16
I
P56 (AIN3)
VD
I
27
VSYNC
KEY-A
17
I
P60 (AIN4)
HD
I
26
HSYNC
KEY-B
18
I
P61 (AIN5)
Y/BL
O
25
Ys
SGV
19
O
P62
B
O
24
BOUT
SGA
20
O
P63
G
O
23
GOUT
GND
21
VSS
R
O
22
ROUT
IIC
-BUS
Fig. 3-2
3-4
<< MICROCOMPUTER TERMINAL NAME AND OPERATION LOGIC >>
No.
Terminal Name Function
In/Out
Logic
Remarks
1
GND
2
BAL
INPUT BALANCE
Out
PWM out
3
REM OUT
REMOTE CONTROL
SIGNAL OUT
Out
Remote control output
4
5
MUTE
SP MUTE
SOUND MUTE OUT
SPEAKER MUTE
Out
Out
Sound mute output
In muting = H
6
DEF POW
7
POWER
POWER ON/OFF OUT
Out
Power control In ON=H
8
LED
POWER LED OUTPUT
Out
Power LED on-control
LED lighting=L
9
POWER LNB
Out
0V
10
11
LNB DET
SCL()
0V
IIC BUS CLOCK OUT
In
Out
12
SDA()
IIC BUS DATA IN/OUT In/Out
IIC bus data input/output 0
13
SYNC VCD
H SYNC INPUT
In
Main picture H. sync signal input
In
Sub tuner AFT S-curve input
In
In
Main tuner AFT S-curve
signal input
Local key detection: 0 to 5V
0V
Out
IIC bus clock output 0
14
15
AFT2 IN
16
AFT1
17
KEY A
UV MAIN S-CURVE
SIGNAL
LOCAL KEY INPUT
18
KEY B
LOCAL KEY INPUT
In
Local key detection: 0 to 5V
19
SGV
TEST SIGNAL OUT
Out
Test signal output In normal=L
0V
20
SGA
TEST AUDIO OUT
Out
Test audio output In normal=L
0V
21
VSS
POWER GROUNDING
—
0V: Gounding voltage
0V
22
23
R
G
R
G
Out
Out
At display on:Pulse
At dispaly on:Pulse
24
B
B
Out
At dispaly on:Pulse
25
Y/BL
BL
26
HSYNC
In
HSYNC for OSD display
Pulse
27
VSYNC
In
VSYNC for OSD display
Pulse
28
29
OSC1
OSC2
DISPLAY CLOCK
DISPLAY CLOCK
Out
In
4.5MHz
Pulse
Pulse
30
TEST
TEST MODE
In
GND fixed
0V
31
XIN
SYSTEM CLOCK
In
System clock input
8MHz pulse
32
XOUT
SYSTEM CLOCK
Out
System clock output 8MHz
8MHz pulse
33
RESET
SYSTEM RESET
In
System reset input (In reset=L)
5V
34
35
SW IN
RMT IN
IN
In remote control pulse input=L
36
SYNC AV1
REMOTE CONTROL
SIGNAL INPUT
HSYNC INPUT
In
External H. sync signal input
In reception of
remote pulse
Pulse
37
SCL1
IIC BUS CLOCK OUT
Out
IIC bus clock output 1
Pulse
38
SDA1
IIC BUS DATA IN/OUT In/Out
IIC bus data input/output 1
Pulse
39
GND
40
NC
41
42
ACP
VDD
Out
At dispaly on:Pulse
0V
NSYNC INPUT
POWER
In
—
AC pulse input
5V
3-5
5V
5. EEPROM (QA02)
EEPROM (Non volatile memory) has function which, in spite of power-off, memorizes the such condition as channel selecting
data, last memory status, user control and digital processor data. The capacity of EEPROM is 8k bits. Type name is 24LC08BI/
P or ST24C08CB6, and those are the same in pin allocation and function, and are exchangeable each other. This IC controls
through I2C bus. The power supply is common to the EEPROM and the main MICOM. Pin function of EEPROM is shown in
Fig. 3-3.
EEPROM(QA02)
Device address
GND
A0
1
8
Vcc + 5V
A1
2
7
NC
A2
3
6
SCL
Vss
4
5
SDA
I2C-BUS line
Fig. 3-3
6. ON SCREEN FUNCTION
ON SCREEN FUNCTION indicates data like channel, volume. Formerly, exclusive use of OSD IC was used, but in N5SS,
the OSD function is within the main microcomputer. Pin function concerning on-screen data generation is shown in Fig. 34. Oscillation clock of OSD is approx. 4.5MHz. 9MHz which becomes multiplied by two to become the dot clock i slocated
within the microcomputer. For oscillation, a coil TRF1160D (LA02) is used.
QA01
OSC2
O
29
OSC2
OSC OUT
OSC1
I
28
OSC1
OSC IN
VD
I
27
VSYNC
H. SYNC SIGNAL
HD
I
26
HSYNC
V. SYNC SIGNAL
Y/BL
O
25
Ys/Ym
HALF TONE SIGNAL
B
O
24
BOUT
G
O
23
GOUT
R
O
22
ROUT
Fig. 3-4
3-6
COLOR SIGNAL
VG
7. SYSTEM BLOCK DIAGRAM
QA01
TMP87CS38N-3152
QA02
MEMORY
24LC08B1/P
SDA
SCL
5
6
11
SCL 0
12
SDA 0
SDA 1
38
SCL 1
37
RMT
35
KEY-A
17
KEY-B
18
26
HSYNC
V. SYNC PULSE
27
VSYNC
RST
33
22
R
VDD
42
23
G
GND
1
24
B
VSS
21
25
YS/TM
REMOTE CONTROL
OUTPUT
3
RMT OUT
SOUND MUTE
4
MUTE
SPEAKER MUTE
5
SP MUTE
REMOTE
SENSOR
UNIT
MAIN U/V TUNER
EL446L
SDA
SCL
HY01
H. SYNC PULSE
VIDEO SIGNAL
PROCESS CIRCUIT
H001
SUB U/V TUNER
EL922L
KEY SWITCH
SDA
POWER
SUPPLY
CIRCUIT
SCL
Q501
VCD
TA1222N
POWER
7
SDA
ACP
41
27
LED
8
XIN
31
8MHz
XOUT
32
CLOCK
OSCI
28
6.1MHz
OSCO
29
CLOCK
SGV
19
SGA
20
SIGNAL
OUTPUT
SCL
28
H002
IF/MPX
MVUS345
SDA
Q701
C/C, EDS
XC144144P
DATA CLK
SCL
21
20
MAIN SCREEN
SYNC-AV1
36
SYNC DET.
AFT1 IN
16
AFT DET.
SYCN-AV2
13
AFT2 IN
2
DPC UNIT
QV01
AV SW
TA1218N
SUB SCREEN
SDA
SCL
SYNC DET.
26
27
DATA CLK
AFT DET.
QM01
QY04
DSP
SDA
PIP CONTROL
DATA CLK
6
5
Fig. 3-5
3-7
SCL
8. LOCAL KEY DETECTION METHOD
15
16
S15-1
S16-1
S15-2
S16-2
S15-3
S16-3
S15-4
S16-4
S15-5
S16-5
S15-6
S16-6
S15-7
S16-7
Local key detection in the N5SS chassis is carried out by
using an analog voltage divider-like method which detects
a voltage appearing at the local key input terminals (pins 17,
18) of the microcomputer whenever a key is depressed.
Using this method, a maximum of 14 keys can be interpreted.
The circuit diagram shown at the left is a representation of
the local key circuit. As can be seen from the diagram, when
one of keys among SA-01 to SA-08 is pressed, each of two
input terminals (pins 17, 18) develops a voltage (Vin)
corresponding to the key pressed. (The voltage measurement
and key identification are carried out by an A/D converter
inside the microcomputer along with interpreting software.
Fig. 3-6. Local key assignment
Table 3-1 Local key assinment
Key No.
Function
Key No.
Function
SA-02
POWER
SA-01
DEMO START/STOP
SA-03
CH UP
SA-04
CH DN
SA-05
VOL UP
SA-06
VOL DN
SA-07
ANT/VIDEO, ADV
SA-08
MENU
3-8
9. ENTERING THE SERVICE MODE
11. SERVICE ADJUSTMENT
1. PROCEDURE
(1) Press once MUTE key on the remote hand unit to
indicate MUTE on screen of the television.
(2) Press the MUTE key of remote hand unit again and
keep depressed while depressing the MENU key on
the front of the unit.
1. ADJUSTMENT MENU INDICATION ON/OFF,
MENU key ( on TV set)
2. During display of the adjustment menu, the following
functions are possible:
a) Selection of adjustment item :
POS UP/DN key (on TV/remote unit)
b) Adjustment of each item :
VOL UP/ DN key (on TV / remote unit)
c) Direct selection of adjustment item
R CUTOFF
: 1 POS (remote unit)
G CUTOFF
: 2 POS (remote unit)
B CUTOFF
: 3 POS (remote unit)
d) Data setting for PC unit adjustment
SUB CONTRAST : 4 POS (remote unit)
SUB COLOR
: 5 POS (remote unit)
SUB TINT
: 6 POS (remote unit)
e) Horizontal line ON/OFF : VIDEO (TV)
(NOTE: applies only to direct view)
f) Test signal selection
: VIDEO (remote unit)
* In service mode, serviceable items are limited.
2. During service mode, indication S is displayed at upper
right corner on screen.
10. TEST SIGNAL SELECTION
1. In OFF state of test signal, SGA terminal (Pin 20) and
SGV terminal (Pin 21) are kept at a “L” condition.
2. The function of VIDEO test signal selection is cyclically
changed with each depression of the VIDEO key (on the
remote control unit).
Table 3-2
Test Signal No.
3. Test audio signal ON / OFF : 8 POS (remote unit)
* Test audio signal : 1kHz
Name of Pattern
0
Signal OFF
1
All black signal + R single color (OSD)
2
All black signal + G single color (OSD)
3
All black signal + B single color (OSD)
4
All black signal
5
All white signal
6
W/B
7
Black cross bar
8
White cross bar
9
Black cross hatch
10
White cross hatch
11
White cross dot
12
Black cross dot
13
H signal (bright area)
14
H signal (dark area)
15
Black cross + G
4. Self check display
: 9 POS (remote unit)
* Cyclic display (including ON/OFF)
5. Initialization of memory :
CALL (remote unit) + POS UP (TV)
6. Initialization of self check data :
CALL (remote unit) + POS DN (TV)
7. BUS OFF :
CALL (remote unit) + VOL UP (TV)
(3) SGA (audio test signal) output should be square
wave of 1kHz.
3-9
12. FAILURE DIAGNOSIS PROCEDURE
The N5SS chassis is equipped with a self diagnosis function inside, used for troubleshooting.
1. CONTENTS TO BE CONFIRMED BY CUSTOMER BEFORE SERVICE CALL IS MADE
Table 3-3
Contents of self diagnosis
Display items and actual operation
A. DISPLAY OF FAILURE INFORMATION
IN NO PICTURE (Condition of display)
1. When power protection circuit operates;
2. When I2C-BUS line is shorted;
Power indicator lamp blinks and picture does not come.
1. Power indicator red lamp blinks. (0.5 seconds interval)
2. Power indicator red lamp blinks. (1 seconds interval)
If these indication appears, repairing work is required.
2. CONTENTS TO BE CONFIRMED BY SERVICER (Check in self diagnosis mode)
Table 3-4
Contents of self diagnosis
Display items and actual operation
Contents of self diagnosis
Display items and actual operation
<Countermeasure in case that phenomenon always arises.>
B. Detection of shortage in BUS line
C. Check of comunication status in BUS line
(Example of screen display)
D. Check of signal line by sync signal detection
SELF CHECK
E. Indication of part code of microcom.(QA01)
Part coce of QA01
NO. 239XXXX
F. Number of operation of power protection circuit
POWER: 000000
Number of operation of
power protection circuit
BUS LINE: OK
Short check of bus line
BUS CONT: OK
BLOCK: UV
Communication check of
busline
V1 V2
QV01, QV01S
E
F
B
C
D
3. EXECUTING SELF DIAGNOSIS FUNCTION [CAUTION]
(1) When executing block diagnosis, select first the desired input signal source (U/V BS VIDEO1,2,3) screen, and then enter
the self diagnosis mode.
(2) When diagnosing other input modes, repeat the diagnosis routines after source selection. The test signals and/or routines
apply only to the video source selected at the time of testing.
(PROCEDURE)
(1) Place the unit in the service mode.
(2) Press the “9” key on the remote control will display the self diagnosis results on screen.
With each key press the mode will change as shown below.
SERVICE mode
SELF DIAGNOSIS mode
(3) To exit from the service mode, turn the power off via the front panel or remote control.
3-10
4. UNDERSTANDING THE RESULTS OF THE SELF DIAGNOSIS FUNCTION
See Fig. 3-7 .
(Example of screen display)
SELF CHECK
NO. 239XXXX
POWER: 000000
Part coce of QA01
Number of operation of
power protection circuit
E
F
BUS LINE: OK
Short check of bus line
B
BUS CONT: OK
BLOCK: UV
Communication check of
busline
V1 V2
QV01, QV01S
C
D
Fig. 3-7
Table. 3-5
Item
Contents
BUS LINE
Detection of bus line short
Instruction of results
Indication of OK for normal result, NG for abnormal
Indication of OK for normal result
Indication of failure place in abnormality
(Failure place to be indicated)
QA02 NG, H001 NG, Q501 NG, H002 NG
QV01 NG, Q302 NG, QY02 NG, HY01 NG
QD04 NG, QM01 NG, Q701 NG
BUS CONT
Communication state of bus line
Note 1. The indication of failure place is only one
placet though failure places are plural. When
repair of a failure place finishes, the next
failure place is indicated. (The order of
priority of indication is left side.)
BLOCK: UV1
UV2
V1
V2
The sync signal part in each video signal
supplied from each block is detected.
Then by checking the existence or non of
sync part, the result of self diagnosis is
displayed on screen. Besides, when “9” key
on remote unit is pressed, diagnosis
operation is first executed once.
*Indication by color
• Normal block
:Green
• Non diagnosis block :Cyan
3-11
<Clearing the self diagnosis results>
While the error count state is displayed upon the screen, press the “CHANNEL DOWN” button on TV set
pressing “DISPLAY” button on remote unit.
[CAUTION]
All ways observe the following caution, when in the
service mode screen.
White
Yellow
Cyan
Green
• Do not press the “CHANNEL UP” button. This will cause
initialization of the memory IC. (Replacement of memory
IC is required.
• Do not initialize self diagnosis result. This will change user
adjusting contents to factory setting value. ( Adjustment is
required.)
Magenta
Red
Blue
( COLOR BAR SIGNAL)
Color elements are positioned in sequence of high brightness.
<Troubleshooting method utilizing internal test signal> (VIDEO INPUT 1 terminal should be open.)
(1) With service mode screen, press VIDEO button on remote unit. If inner video signal can be received, QV01 and after are
normal.
(2) With service mode screen, press “8” button on remote unit. If sound of 1kHz can be heard, QV01 and after are normal.
* By utilizing signal of VIDEO input terminal, each circuit can be checked. (Composite video signal, audio signal)
3-12
13. TROUBLE SHOOTING CHARTS
(1) TV DOES NOT TURNED ON
TV does not turned on.
YES
Relay sound
NO
NG
Check of voltage at pin 7 of QA01
(DC 5V).
OK
Check power circuit.
8MHz oscillation waveform
at pin 32 of QA01.
NG
OK
Check OSC circuit.
Replace QA01.
NG
Pulse output at pins 37 and 38 of QA01.
OK
Voltage check at pin 32 of QA01
(DC 5V)
NG
OK
Check reset circuit.
Check relay driving circuit.
Replace QA01.
3-13
(2) NO ACCEPTION OF KEY-IN
Key on TV
NG
Voltage change at pins 17, 18 of
QA01 (5V to 0V).
OK
Check key-in circuit.
Replace QA01.
Remote unit key
NG
Pulse input at pin 35 of QA01,
When remote unit key is pressed.
OK
Check tuner power circuit.
Replace QA01
(3) NO PICTURE (SNOW NOISE)
No picture
NG
Voltage at pins of +5V, and 32V.
OK
Check H001.
Check tuner power circuit.
3-14
(4) MEMORY CIRCUIT CHECK
Memory circuit check
NG
Voltage check at pin 8 of QA02 (5V).
OK
Check power circuit.
NG
Pulse input at pins 5 and 6 of QA02
in memorizing operation.
OK
Check QA01.
Replace QA02.
Note: Use replacement parts for QA02.
Adjust items of TV set adjustment.
(5) NO INDICATION ON SCREEN
No indication on screen.
NG
Check of character signal at pin 23
of QA01. (5VP-P)
OK
Check V/C/D circuit.
Input of OSC waveform at pin 29 of QA01
with indication key pressed.
NG
OK
Check OSC circuit.
Check of sync signal at pins 26, 27 of QA01.
OK
Check sync circuit.
Replace QA01.
3-15
NOTES
3-16
SECTION IV
AUDIO OUTPUT CIRCUIT
4-1
1. OUTLINE
The main amplifiers and woofer output amplifiers use a
bipolar IC (TA8256H) and develop output powers of
10Wx2 + 13W.
2. THEORY OF OPERATION
2-1. Operation of TA8256H
The TA8256H is a modified version of the TA8128AH
which was used in the N4SS chassis as an audio ouput IC.
In the TA8256H, one channel has been added and up to 3
channels can be used. Performance for each channel is the
same as that of the TA8218H. Fig. 4-1 shows a block
diagram of the IC.
Vcc
25.5V
47m F
1m
F
L
L
4
47m F
6
9
RIPPLE FILTER
4k
Vcc
OUTPUT-2
AMP-2
30k
470m F
8
2.2W
3 PRE
GND
POW 10
GND
2.2W
(R)
F
12
AMP-3
R
R
0.12m F
RL (R)
350W
1m
RL (L)
0.12m F
350W
470m F
OUTPUT-3
2
4k
30k
5
(mute)
MUTING
(mute Tc)
1m
7
30k
F
4k
W
1
W
OUTPUT-3
350W
AMP-1
11
(S) or (W)
1000m F
2.2W
0.12m F
20kW
Fig. 4-1
4-2
RL (W)
SECTION V
DSP CIRCUIT
5-1
1. ORIGINS OF DOLBY SURROUND
into left, center equally into left and right, and right into rightplaying a Dolby Stereo soundtrack over two speakers
reproduces the entire encoded soundtrack. There is but one
exception: the surround signal, though audible, is not
reproduced in its proper spatial perspective. When the first
home decoder was developed in 1982, its goal was to restore
this lone missing dimension.
Before we discuss decoders, it is necessary to see how the MP
Matrix encoder works. Referring to the conceptual diagram
in Fig. 5-1, the encoder accepts four separate input signals;
left, center, right, and surround (L, C, R, S), and creates two
final outputs, left-total and right-total (Lt and Rt).
Dolby Stereo movies and Dolby Surround video and television
programs include an additional sonic dimension over
conventional stereo productions. They are made using a Dolby
MP (Motion Picture) Matrix encoder, which combines four
channels of audio into a standard two-channel format, suitable
for recording or transmitting the same as regular stereo programs.
To recapture the dimensional properties brought by the
additional channels, a Dolby Surround decoder is used. In the
theatre, a professional decoder is part of the Dolby Stereo
cinema processor used to play 35 mm stereo optical prints.
The decoder recovers the left, center, and right signals for
playback over three front speakers, and extracts the surround
signal for distribution over an array of speakers wrapped
around the sides and back of the theater. (These same
speakers may also be driven from four of the six discrete
tracks on 70 mm Dolby Stereo magnetic prints, but in this
case no decoder is needed.)
Home viewing of movies on video has become extremely
popular, and with the advent of stereo VCR's, stereo television
and digital video discs, the audio side of the video presentation
has improved considerably, inviting the use of full-range
sound reproduction. The ability to deliver high quality audio
in these formats made it easy to bring MP Matrix-encoded
soundtracks into the home as well, thus establishing the
foundation for Dolby Surround.
The L and R inputs go straight to the Lt and Rt outputs without
modification, and the C input is divided equally to Lt and Rt
with a 3 dB level reduction (to maintain constant acoustic
power). The S input is also divided equally between Lt and Rt,
but it first undergoes three additional processing steps:
a. Frequency bandlimiting from 100 Hz to 7 kHz.
b. Encoding with a modified from of Dolby B-type noise
reduction.
c. Plus and minus 90-degree phase shifting is applied to
create a 180-degree phase differential between the
components feeding Lt and Rt.
It is clear there is no loss of separation between the left and right
signals; they remain completely independent. Not so obvious
is that there is also no theoretical loss of separation between the
center and surround signals. Since the surround signal is
recovered by taking the difference between Lt and Rt, the
identical center channel components in Lt and Rt will exactly
cancel each other in the surround output. Likewise, since the
center channel is derived from the sum of Lt and Rt, the equal
and opposite surround channel components will cancel each
other in the center output.
The ability for this cancellation technique to maintain high
separation between center and surround signals requires the
amplitude and phase characteristics of the two transmission
channels to be as close as possible. For instance, if the center
2. THE DOLBY MP MATRIX
One of the original goals of the MP Matrix was to enable
Dolby Stereo soundtracks to be successfully played in theaters
equiped for mono or two-channel stereo sound. This allows
movies to be distributed in a single optical format, and
furtheremore results in complete compativility with home
video media without requiring separate soundtrack mixes.
Since the three front channels of the MP Matrix are assembled
in virtually the same way as a conventional stereo mix --- left
Left
Center
Right
+
+
+
+
-3dB
+
Surround
-3dB
B.P.F
DOLBY NR
ENCORDER
Lt
+90 DEG
-90 DEG
+
+
+
Fig. 5-1 Conceptual Dolby Stereo/Dolby Surround encoder
5-2
Rt
4. DSP CIRCUIT
channel components in Lt are not identical to the ones in Rt
as a result of a channel balance error, center information will
come out of the surround channel in the form of unwanted
crosstalk.
A surround component (L-R) is extracted from L, R audio
signals coming through the AV SW in the matrix circuit as
shown in Fig. 5-3. The surround component enters the DSP
circuit through the LPF.
The signal is A/D converted, delayed by an arbitrary time of
0~100 msec (every 3.2 msec) by digital process and then D/
A converted and outputs from the DSP IC. The DSP IC
develops two outputs; (LO) for FRONT (LO) and (RO) for
REAR and each output is controlled by the microcomputer
for each surround mode. The output signal (LO) for FRONT
is added and subtracted with the input signal in a matrix
circuit and output from the front speaker in passing through
the audio processor and main amplifiers.
At the same time, the output signal (RO) for REAR is fed to
the Dolby NR circuit, but switched to "Dolby surround"
mode, and then output from the rear speaker in passing
through audio processors and rear main amplifiers.
In this case, the DSP stands for not only a simple digital
surround processor but also a digital surround field processor.
That is, it works to give a simple surround effect but to give
effect as if the listener can feel reality suitable for the
programs. For example, it aims to give the listeners a reality
matching to each program they are enjoying in their home
listening room so that they can obtain reality of big concert
hall or feel as if they are watching a move at a reserved seat
in a movie theater.
3. THE DOLBY SURROUND DECODER
This leads us to the original Dolby Surround decoder. The
block diagram in Fig. 5-2 shows how the decoder works.
Except for level and channel balance corrections, the Lt input
signal passes unmodified and becomes the left output. The Rt
input signal likewise becomes the right output. Lt and Rt also
carry the center signal, so it will be heard as a "phantom"
image between the left and right speakers, and sounds mixed
anywhere across the stereo soundstage will be presented in
their proper perspective. The center speaker is thus shown as
optional since it is not needed to reproduce the center signal.
The L-R stage in the decoder will detect the surround signal
by taking the difference of Lt and Rt, then passing it through
a 7 kHz low-pass filter, a delay line, and complementary
Dolby noise reduction. The surround signal will also be
reproduced by the left and right speakers, but it will be heard
out-of-phase which will diffuse the image.
Since the heart of the decoding process is a simple L-R
difference amplifier, it is referred to generically as a "passive"
decoder. This is to distinguish it from decoders using active
processes to enhance separation which are known as "active"
decoders.
INPUTS
OUTPUTS
Lt
INPUT
BALANCE
CONTROL
Rt
L
L
R
R
C
LEVEL
CONTROL
Left
MASTER
LEVEL
CONTROL
C
Optional passive center signal
S
L-R
ANTIALIAS
FILTER
MODIFIED
B-TYPE NR
DECODER
DELAY SET
AUDIO
DELAY
7 kHz
LOW PASS
FILTER
Fig. 5-2 Passive surround decoder block diagram
5-3
Center
Surround
L+R
S
Right
From
A/V SW
QD08
Input Balance
QD02
DSP
Front Addition Circuit
QD01
Input Buffer
12
L 5
14
7
L
IN
10
R
8
R
6
L
10
L+S
L
L
Speaker
R
R-S
9
R
5
3
MATRIX 7
(L-R CIRCUIT) (L-R)
QD01
5-4
Fig. 5-3 Block diagram of DSP circuit
4
8
R
Q670
Front amp
LPF
1
3
QD01
L+R
1
LPF
Sycrone
(Super woofer)
QD02
QD03 DSP IC YM7128 B
VC
TO
A/D
CONT
Audio
Processor
(H002)
DIGITAL DELAY
Buffer
VL
D/A
LO
From Micro
computer
3
1 5
LPF 7
7
QD05
BUS
QD04
CONVERT
Buffer
VR
D/A
RO
5
8
QD06
LO
QD05
DQ06
7 3
LPF
1
Dolby NR
6
9
14
12
QD07
DQ02
Q640
Rear Amp
+S
L-R
L
Speaker
R
As shown in Fig. 5-4, a sound emitted in a sound field can
be classified as a direct sound which directly reaches ears of
a listener, and reflected sound which comes after collision
with a wall as shown by dotted line or comes after several
times of collision as shown by double dotted lines. The
listeners are determining that they are listing in what type of
location by perceiving time difference and volume level
difference between the direct sound and the reflected sound.
For more detail, this situation can be expressed with the
direct sound, initial reflection sound coming after one time of
reflection, and trains of reverberation sound in later period as
shown in Fig. 5-5.
The DSP circuit develops these initial reflection sound and
the reverberation sound artificially and add them to the
original sounds, thereby creating rhe effect that allows the
listeners in the home listening room to feel as if they are
listening in an original location.
The DSP IC YM7128B has eight separate output taps and
their delay time and the output levels can be specified
separately, so, various sound fields can be selected by varying
the initial reflection sound. Moreover, the IC has an internal
feedback loop which controls the delay time and the output
level in considering the later time reverberation sound.
Direct Sound
Direct Sound
Sound Level
Initial Reflection
Sound
Initial Reflection Sound
Reverberation Sound
Reverberation
Sound
:
:
Time
Fig. 5-4
Fig. 5-5
5-5
5. DSP (Digital Surround Processor) IC
delay input after it is added to the doubler described above.
The output of eight taps T1 to T8 is added after performing
reduction processing by GL1~GL8, GR1~GR8, and reduction
processing is performed by the digital attenuator VL or VR,
and an analog output is created by D/A converter after
passing through digital filter, comes out from pin 7 or 8.
The digital attenuated value, delay time and the coefficient of
FIR type low pass filter are set by writing the data on the
register.
This process is performed by loading three data from sub
microcomputer to microcomputer interface.
This unit has four modes as surround mode. The setting
values are described in Table 5-1.
Input signal entered into analog input pin 4 of DSP IC QD03
(YM7128B) is converted to 14 bit digital signal with the
sampling frequency 23.6 kHz by A/D converter of 14 bit
floating system, and enters digital delay circuit through
digital attenuator VM and doubler.
The digital delay circuit has nine output taps, and the delay
time of each tap can be controlled independently, also each
tap position can be switched by T0 to T8 register.
In a minute, the T0 output passes through the primary FIR
(Finite Impulse Response) type low pass filter, and reduction
processing is performed by VC, then it feed-backed to the
Table 5-1 DSP control factor
Mode
OFF
Control
DOLBY
SURROUND
THEATER
STADIUM NIGHT CLUB CONCERT
HALL HALL
-VM (IN)
-•¥
P-0
P0 ¥
P0
P0
P0
VL (LO)
VR (RO)
-•¥
P0
P0~ -•
P0
P0~ -¥•
P0
P0~ --¥•
P0
P0~ --¥•
P0
VC (Echo)
-•¥
-•¥
M-6
M-10
M-8
GL1
P-4
M-2
M-2
P-2
2
M-6
-•¥
P-4
P-10
3
P-12
P-6
P-16
4
5
P-12
-•¥
M-10
-•¥
-•¥
UNIT
dB
6
7
8
GR1
P0
2
3
-•¥
P0
P-18
4
-•¥
5
P-2
P-6
P-4
6
M-2
M-6
P-8
7
P-8
M-10
P-8
8
T0 (Delay)
P-14
51.6
0
P-10
0
100.0
P-12
19.4
1
19.4
12.9
93.6
12.9
71.0
2
0
38.7
100.0
19.4
83.9
3
71.0
100.0
22.6
100.0
4
87.1
0
29.0
0
5
6
29.0
45.2
6.5
9.7
64.5
80.7
7
83.9
25.3
90.4
8
100.0
35.5
100.0
C0 (Filter)
0
0
1
5-6
msec
0.71875
0.59375
0.875
—
0.28125
0.40625
0.125
—
XD01
CD27
RD32
CD29
CD28
D01
RD33
QD03
11
XO
12
16
XI
/IC
Vss
C1
REFERENCE
VOLTAGE
GENERATION
CV
5
CD22
RD26
From
Input LPF
4
AIN
VM
A/D
CONVERTER
1
VC
LD01
TIMING GENERATION
D
AVDD
+B (5V)
2
C2
CD21
TO
CD20
DIGITAL DELAY
T8 T7 T6 T5 T4 T3 T2 T1
CD15
GL1
CH
GL2
3
GL3
5-7
Fig. 5-6
CD23
GL4
VL
2fs
GL5
/TI
6
GL6
D/A
CONVERTER
LO
7
DC26
To LPF Output
(For FRONT ch)
GL7
GL8
GL1
GL2
GL3
GL4
GL5
MICROCOMPUTER
INTERFACE
DIN AO SCI
VDD
15
From
14
VR
2fs
D/A
CONVERTER
Bus convert
(ICD04)
To LPF Output
(For REAR ch)
8
DC25
GL6
GL7
GL8
VSS
AVSS
10
13
RO
9
NOTES
5-8
SECTION VI
A/V SWITCHING CIRCUIT
6-1
1. OUTLINE
The A/V switching circuit selects the desired video and
audio signals from the various inputs. It is controlled by the
microcomputer through IIC bus.
2. IN/OUT TERMINALS
TUNER INPUT
EXTERNAL INPUT
OUTPUT
U/V Tuner (Main)
U/V Tuner (PIP)
VIDEO 1 With S-terminal
VIDEO 2
VIDEO 3 (Front) With S-terminal
VIDEO OUTPUT (V, L, R)
AUDIO ON SUB-PICTURE
3. CIRCUIT OPERATION
This circuit consists of A/V SW IC; TA1218N (QV01), and
selects signals from U/V tuner (Main), U/V tuner (PIP),
E1, E2 and E3.
3-1. Composite Video Signal
The selected video signal is output to pin 38 of QV01, and
separated by comb filter into Y an C. The resulted signal
is input to pins 30 and 32 of QV01, and is output to pins 36
and 34 to be supplied to Q501 (V/C/D).
Video signal for PIP is output to pin 42 of QV01, and is
supplied to PIP unit (ZY01).
3-2. S-Video Signal
When a cable is connected to S-VIDEO terminal, inner
switch of S-VIDEO terminal is shorted to ground to turn off
the transistor (QV05 for VIDEO1 input) for S-VIDEO
terminal detection. Then chroma input terminal (Pin 14 for
VIDEO1 input) of QV01 turns on.
6-2
AV SW CIRCUIT
HY01
PIP TUNER/IF
H002
IF/MTS/A. PRO
A
V
V
EQ
A
DSP
QV01 TA1218N
L/R in
18
C in
17
R in
16
S in
15
QA01
SYNC in
SYNC OUT
26
L in
PIP TV in
28
14
C in
PIP L in
29
13
R in
Y in
30
Y out
12
S in
PIP R in
31
V in
11
L in
C in
32
C out
10
V in
9
R in
C out
34
8
L in
R out
35
7
V in
Y out
36
6
R in
L out
37
5
L in
V out
38
2
PIP R out
1
PIP L out
VIDEO 3
VIDEO 1
VIDEO 2
PIP AUDIO
OUT JACK
COMB
FILTER
C in
Q501
Y in
PIP
PIP V out
TP48E90 ONLY
A/V OUT
JACK
Fig. 6-1
6-3
42
V in
NOTES
6-4
SECTION VII
VIDEO PROCESSING CIRCUIT
7-1
1. OUTLINE
This circuit converts and amplifies video signal (Luminance
and chroma signals) separated into Y/C, to original color
signal, and is supplied to CRT Drive circuit.
2. SIGNAL FLOW
Signal flow chart is shown in figure 6-1 Block diagram.
(1) Luminance signal is input to pin 15 of Q501, and enters
into delayline inside Q501 to be output to pin 4.
(2) Chroma signal is input to pin 13, and I/Q signal which
is demodulated in color, is output to pins 5 and 6, and
next supplied to pins 51 and 52.
(3) The signal is processed on luminance and chroma
signals, and is converted to original color signal (R,G,B)
by RGB matrix. Next the signal is superimposed with
OSD signal to be output to pins 41, 42 and 43, and is
supplied to CRT Drive circuit.
(4) The signal for Scan Modulation is processed with
differential in Q501 to be output to pin 48 Besides, at
terminal for adjustment TP501, luminance and chroma
signals are automatically output according to the
selected items of service mode.
3. CIRCUIT OPERATION
All processing operation of video signal are done inside
Q501. The outline of Q501 (TA1222N) is explained in the
next section. Here, major terminals excepting input/output
terminals of Q501 are described.
Table 7-1
Pin No.
Name
Description
Pin 1
CW output
3.58MHz synchronized with burst is output. This is used for clock of comb filter.
Pin 10
Xtal 1
Terminal for 3.58MHz OSC crystal
Pin 11
APC filter
Terminal for phase detection of color sync (OSC frequency control)
Pin 18
SYNC
Sync-separated sync signal is output. It is used for detecting no signal in
microcomputer.
Pin 30
HD
Terminal for output of HD pulse syncronized with horizontal sync., and for input
of black expading mask pulse. It is used for timing pulse of OSD, C.C (Closed
Caption) in micro- computer.
Pin 32
Ys
OSD change-over pulse input: Ys of OSD is input.
Pin 45
ABL
Terminal for ABL control input
Pin 47
Ym
Input of pulse for half tone control: It is supplied from microcomputer.
Pin 49
APL DET
Detecting average level of video signal for correction of DC transmission
Pin 50
BLACK DET
Detecting black area of video signal for black expading circuit
Pin 54
COL
Terminal for peak-hold of color limiter
Pin 55
DAC1
Test point (TP501): Functioning test point in service mode
7-2
NOTES
7-4
SECTION VIII
V/C/D/IC
8-1
1. OUTLINE
This IC enables more precise picture setting than that of former IC (TA8845N) by means of large scale employment
of IIC bus, and reduces many peripheral components by containing filters inside.
The main features (comparing TA8845) are as follows.
2. LARGE SCALE EMPLOYMENT OF BUS CONTROL OF PARAMETER FOR PICTURE
CONTROLS
Soft method of picture making
Table 8-1
Former/TA8845N
TA1222N
* Black expanding start point
External constant
BUS control
* DC transmission correction quantity point
External constant
BUS control
* Black level correction quantity
External constant
BUS control
* Each ABCL characteristic
External constant
BUS control
3. EMPLOYMENT OF CONTAINING EACH VIDEO BAND FILTER INSIDE
Employment of automatic adjustment circuit by Fsc to absorb deviation / Employment of deviation aborbing method by high
S/N filter and mask triming using fixed CR
Table 8-2
Former/TA8845N
TA1222N
Apa-con DL inside
Inside
* Chroma TO/BPF
External
Inside
* Velocity modulation processing circuit
External
Inside
* Fsc trap for chroma demodulation output
External
Inside
* Y-DL
4. EMPLOYMENT OF CONTAINING EACH FILTER (FOR S/H) INSIDE
Circuit operation by extremely low current / Employment of leak current cancel circuit Employment of detection circuit
which does not suffer from influence of stray capacity
Table 8-3
Former/TA8845N
TA1222N
* Chroma ACC / killer filter
External
Inside
* Y / color difference clamp filter
External
Inside
* Filter for filter automatic adjustment
External
Inside
* AFC 2 filter
External
Inside
8-2
5. LOW COST OF IC
* Involving peripheral components inside ——> Down sizing of chip ——> Newly employment (NPN Tr area ratio to former
: -25%) of miniature process (PLAS-1 S process)
* Involving peripheral components inside——>Increasing of power consumption——>2 power supply system (5V / 9V
used)
* Involving peripheral components inside ——> Reducing of number of elements ——> Employment of new circuit
(1) Reducing of gate (change of preset method) of register for IIC decoder
(2) Reducing of DAC elements (employment of rudder type DAC + temperature compensation circuit)
(3) Deletion of chroma CW, ACC (employment of 90 degree shift phase circuit with automatic adjustment)
8-3
3'5" VCD
BLK/AFC IN
BENDING
CORRECTION
20
21
25
24
19
H. out
AFC1
17
Daf vCC
SYNC IN
VCD BLOCK DIAGRAM (TA1222N)
22
23
GND (DEF) VCC (DEF)
H. V.
SYNC SEP
V. Sep 16
PHASE DET
<APC-1>
V. SEP
32 FM VCO
H. BLK
H.
COUNT DOWN
H.
PARABOLA
PHASE DET
<APC-2>
H. PHASE
SHIFT
H. DRIVE
H. DUTY
SW
Y.
COUNT DOWN
Y.P OUT
31 VER OUT
SYNC
OUT
V.
SYNC SEP
18 SYNC OUT
27 SDA
Y IN
SYNC CHIP
CLAMP
15
DELAY
LINE
FDC TRAP
SW
D/A
CONVERTER
REGISTER
I2C BUS
DECODER
DELAY LINE
DELAY LINE
SW
26 GND
19 SCL
BPF
CHROMA IN
SW
13
4
Y1 OUT
TOK
29 GND
GND
GND
34
ACC AMP
TOF
ACC DET
SUB
COLOR
SW
GAMMA
CORRECTION
BLACK
LEVEL COR.
BLACK
STRETON
Y. CLAMP
53 Y2 OUT
B.C
RESTORE
A.P.L DET
BLACK
PEAK DET
WHITE
PEAK DET
30
SHARPNESS
DELAY LINE
HPF
TM AMP
VM MUTE
28 VM OUT
SHARPNESS
CONTROL
T. NR AMP
SUB CONT
UNI COLOR
VCC
9V
12
(88)
BLACK PEAK
HOLD
39 APL DET
APC FILTER
11
APC DET
P/N IDENT
BET
CHROMA
BLK
X tal-1
(3.58MHz)
10
CHROMA
VCO
CW
MATRIX
CHROMA
DEMOD.
FILTER
AUTO ADJ
LPH
FSC TRAP
X tal-2 (PAL)
8
I IN
51
Q IN
VCC
(98)
9
X tal-3 (PAL)
52
S
R
T
WPS
HALF TONE
CLAMP
26
5
Q OUT
6
Y OUT
33 B IN
IQ/UV
CLAMP
FRESH
COLOR
IQ UV
CONVERT
SW
UNI COLOR
COLOR
TINF
DELAY
TIME
AXIS
G-Y MATRIX
CLAMP
HALF
TONE
COLOR
PEAK DET
CDE
COLOR
GAMMA
RGB
BRIGHT
CLAMP
CONTRAST
34 G IN
35 R IN
YS SW
36 OSD Ys IN
37 OSD B IN
CLAMP
OSD AMP
38 OSD G IN
39 OSD R IN
SECAM
CONTROL
COLOR
SYS IDENT
DAC 1/2
CW OUT
1H DL
CONTROL
S.C.P
OUT
HD OUT
EXT EFP IN
SW
PEAK
ACL DET
ABCL AMP
DRIVE
CLAMP
BLK
CUT OFF
RGB OUT
POWER OFF IN
YM SW
1
7
2
30
HD OUT/BLACK
EXPAND MATRIX
VCC (98) GND
SCP OUT
(SAND CASTLE)
3
1H DL CONTROL
(FOR PAL)
SECAM CONTROL
(FOR SECAM)
56
CW OUT/
COLOR IDENT.
DAC 2
RGB
MATRIX
HI BRIGHT
COLOR
47
8-4
46
44
41 42 43
R OUT
55
B OUT
DAC 2
G OUT
54
YM IN
COLOR LIMITER
YS SW
22 Ys IN
25 ABL IN
SECTION IX
PIP MODULE
9-1
PMUS 02H (SN:23148232)
B-Y OFFSET
R-Y OFFSET
TINT
RY54 RY55
RY50
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
PIN
I/O
NAME
PIN
I/O
1
0
YS
9
I
5V
2
-
NC
10
I
GND
3
I
GND
11
I
VD
12
I
HD
4V
0V
NAME
350m S
4.2V
0V
4.8V
4
O
R OUT
4.1V
3.0V
4.8V
5
O
G OUT
1m S
13
4.1V
I/O
10m S
4.2V
6V
SCL
Or
-0.9V
6
O
B OUT
7
I
GND
4.8V
4.1V
4.8V
8
I
PIP VIDEO
2.8V
9-2
14
I/O
SDA
15
-
NC
B CHASSIS
0V
C CHASSIS
PMUS02H
<BLOCK DIAGRAM OF PIP MODULE>
RY55 RY54
PIP VIDEO
8
R OUT
36 VIDEO
IN
B-Y 14
OUT
51 BI
BO 67
R-Y 13
OUT
49 RI
RO 65
47 YI
YO 64
9-3
Y-OUT 12
HD 10
VD 11
QY01
m PC 1832GT
(PIP V/C/D)
VD
11
HD
12
SLICE
WAVE FORM
MODULATION
78 HDCN
HDPN 18
76 VDCN
VDPN 16
QY03
TC9083F
(PIP PROCESSOR)
19 B-Y
IN
18 R-Y
IN
16 YIN
R OUT 23
4
G OUT
G OUT 24
5
B OUT
B OUT 25
6
QY01
m PC1832GT
(PIP V/C/D)
NOTES
9-4
SECTION X
SYNC SEPARATION, H-AFC,
H-OSCILLATOR CIRCUITS
10-1
1. SYNC SEPARATION CIRCUIT
The sync separation circuit separates a sync signal from a
video signal and feeds it to an H and V deflection circuits.
The separation circuit consists of an amplitude separation (H
and V sync separation circuit) and a frequency separation
circuit (V sync separation circuit) which performs the
separation by using a frequency difference between H and V.
In the N5SS chassis, all these sync separation circuits are
contained in a V/C/D IC (TA1222N).
Fig. 10-1 shows a block diagram of the sync separation
circuit.
Sync
input
Composite
video
signal
17
H sync siganl
Q501
H. V SYNC
SEPARATION
CIRCUIT
V SYNC
SEPARATION
CIRCUIT
WAVEFORM
SHAPEING
CIRCUIT
Fig. 10-1 Sync separation circuit block diagram
1-1. Theory of Operation
1-1-1. Auto slicer type synchronous separation circuit
When a synchronizing signal is separated, synchronous
separation is made from the beginning with constant voltage
in the conventional synchronous separation circuit. The auto
slider type circuit employed in this time makes synchronous
separation at a constant rate against the synchronizing signal
amplitude. (See Fig. 10-2)
In this method, even if an abnormal signal with small
amplitude is applied, stable synchronizing performance can
be obtained without separating pedestal.
Pedestal Level
D
B
A
B
Sync Separation Level A:B=C:D
b: Small Amplitude Sync. Signal
a: Corect Sync. Signal
Fig. 10-2 Synchronous separation by auto slider system
10-2
V sync signal
(Reset pulse)
1-1-2. V Sync Separation Circuit
To separate a V sync signal from the composite sync signal
consisting of V and H sync signals mixed, two stages of
integration circuits are provided inside the IC. The circuit
consists of a differential circuit and a Miller integration
circuit, and has following functions.
(1) Removes H sync signal component.
(2) Maintain stable V sync performance for a tape recorded
with a copy guard.
(3) Stabilized V sync performance under special field
conditions (poor field, ghost, sync depressed, adjacent
channel best).
The V sync signal separated in this stage is processed in a
waveform shape circuit and then used as a reset pulse in the
V division circuit as stated later.
First, phases of a 32 fH counted-down signal and a H sync
signal contained in broadcasting signal are compared in the
AFCI loop and the loop develops an H pulse signal for the
AFCII loop. That is, when a phase deference 01 exists in
comparison of the phase of fH signal developed by counting
down the 32 fH signal and the phase of H sync signal of the
broadcasting signal, an error signal corresponding to the
phase different is detected and a correction voltage V1
corresponding to the error output is generated. With this
correction voltage, the 32 fH oscillator circuit is controlled.
The correction (control) voltage for the oscillator varies in
direction of positive or negative corresponding to phase
lead or lag of the fH pulse (developed by counting down)
from the H sync signal. As the H oscillator (32 x fH), a
voltage controlled oscillator (VCO), oscillation frequency
and phase of which can be controlled with the control
voltage is used.
Next, an H pulse signal is created from the fH signal counted
down, and the pulse is used instead of the H sync signal in
the AFCII circuit. The AFCII circuit differs in the loop of
the count down circuit and H output circuit.
The AFCII circuit compares phase of a H BLK pulse created
by waveform shaping a AFC pulse from the FBT and a phase
of the H pulse, and detects an error component corresponding
to the phase difference 02 (if exist) and develops a
correction voltage V2 corresponding to the error, thereby
controlling the phase of Q501 H out.
The H output control voltage varies in a positive or negative
direction corresponding to the phase lead or lag of the H
BLK pulse from that of the H pulse. The phase of H out is
varied with the control voltage to make synchronization
with the H pulse phase.
The purpose of the double AFC circuit employed this time
2. H AFC (Automatic Frequency Control)
CIRCUIT
A sync system which performs synchronization with each
waveform of the sync signal as performed in a sync system
in the V circuit is called a direct type sync system. However,
if the synchronization for the H oscillator is carried out with
this method, the H oscillator synchronizes with external
noises and the H synchronization will be disturbed. To
prevent this, an output of the H oscillator is compared with
a reference H sync signal to detect deviations of frequency
and phase. The H oscillator is automatically controlled with
the detected output averaged. This circuit is called an AFC
circuit.
In the N4SS chassis, a conventional AFC circuit is not
employed but a new double AFC circuit built-in the TA1222N
is used. Fig. 10-3 shows the AFC circuit and the block
diagram of the circuit.
SYNC SEPARATION
CIRCUIT
PHASE DETECTION
CIRCUIT
32 x fH
VCO
AFC II LOOP
H COUNT DOWN
(DIVIDING)
PHASE DETECTION
CIRCUIT
AFC I LOOP
FBT PULSE
(AFC PULSE)
Fig. 10-3 H AFC circuit block diagram
10-3
H DRIVE
H OUTPUT
CIRCUIT
is to improve horizontal jitter under signal reception in a
poor electrical field. The jitter in the poor field strength and
distortion due to phase difference are incompatible. That
is,to improve the jitter under poor field strength, response
speed must be slowed by lowering the AFC sensitivity. On
the other hand, to improve distortion due to the phase
difference, the response must be increased by increasing the
AFC sensitivity.
In a conventional AFC circuit, setting of the sensitivity is
carried out at one part only, so an compromise point for both
characteristics must be found. However, with the double
AFC circuit employed this time, for the jitter the AFCI loop
works best with decreasing the sensitivity and for the phase
distortion the AFCII loop works with increasing the
sensitivity.
H Vcc
SYNC
IN
2VP-P
17
20
21
SYNC
SEPARATION
CIRCUIT
H AFC I
CIRCUIT
32 x fH
VCO
3. H OSCILLATOR CIRCUIT
H COUNT
DOWN
3-1. Outline
A 503 kHz (32 x fH) voltage controlled type oscillator with
a ceramic oscillation element is used to generate a clock
pulse and the clock is counted down, thereby obviating the
need of adjustments for both the H and V deflection process
circuit.
H AFC II
CIRCUIT
TA1222N
3-2. Theory of Operation
(1) The H sync signal used as a reference signal enters
from the sync separation circuit to the AFCI circuit. At
the same time, the fH pulse created by counting down
the 32 x fH pulse generated in the ceramic oscillator
enters the H AFCI circuit. Phase difference between
these two signals enters an integration circuit (low pas
Fig. 10-4
10-4
(3)
(4)
(5)
32 x fH VCO
V sync
signal
V WAVEFORM
SHAPE
CIRCUIT
32fH
X 1/8
Reset
pulse
OSC frequency (Hz)
(2)
filter) connected to pin 4 and converted into a DC
voltage (AFC voltage).
The AFC voltage controls frequency (32 x fH) of the
oscillator (VCO).
Fig. 10-5 shows the control characteristics of the VCO.
The H output is obtained by dividing the 32 x fH (503
kHz) of the oscillator with flip-flops. Fig. 10-6 shows
the block diagram of this count down circuit.
The V output is created by dividing the 32 x fH
oscillator output into 1/8, and then by counting the 4 x
fH pulse with a vertical counter which is reset with a
V reset pulse (V sync output signal stated under sync
separation).
That is, the V output is not created by simply counting
down the H by performing V synchronization with a V
reset pulse entering within a window provided for V
synchronization --- called direct type sync system,
thus, the circuit can work for non standard signals.
High
Low
Low
High
AFC voltage (V)
Fig. 10-5
4fH
fH
X 1/4
V
COUNTER
Fig. 10-6 Block diagram of H, V count down circuits
10-5
H OUTPUT
V OUTPUT
NOTES
10-6
SECTION XI
VERTICAL OUTPUT CIRCUIT
11-1
1. OUTLINE
As can be seen from the block diagram, the sync circuit and
the V trigger circuit are contained in Q501 (TA1222N), and
the sawtooth generation circuit and amplifier (V drive circuit)
contained in Q302 (TA8859AP). The output circuit and
pump-up circuit circuits are included in Q301 (TA8427K).
DPS CIRCUIT
Q302 TA8859AP
Q501 TA1222N
SYNC
CIRCUIT
V. TRIGGER
Q301 TA8427K
SAM TOOTH
WAVE GAIN
CIRCUIT
PUMP-UP
CIRCUIT
AMP
OUTPUT
LOGIC
CIRCUIT
Microcomputer
DEFLECTION
YOKE
Fig. 11-1 Block diagram of V deflection circuit
1-1. Theory of Operation
The purpose of the V output circuit is to provide a sawtooth
wave signal with good linearity in V period to the deflection
yoke.
When a switch S is opened, an electric charge charged up to
a reference voltage VP discharges in an constant current
rate, and a reference sawtooth voltage generates at point a.
This voltage is applied to (+) input (non-inverted input) of
an differential amplifier, A. As the amplification factor of
deflection current flows so that the
A is sufficiently high,
voltage V2 at point
becomes equal to the voltage at point
.
S: Switch
Vp
Differential
amplifier
L
A
a
C2
V1
R1
C2
c
V2
R2
R3
Fig. 11-2
11-2
2. V OUTPUT CIRCUIT
2-1. Actual Circuit
D309
C322
+9V
R308
C308
D308
R329
15
+35V
3
D301
14
31
Q302
Q301
4
6
R303
3
FEEDBACK
Q501
C313
6
7
L301
2
C321
R320
C307
5
1
R307
R301
13
R336
8
L462+L463+L464
R306
C309
C314
C311
C306
R313
R330
C305
R304
C319
+27V
R305
Fig. 11- 3
2-2. Sawtooth Waveform Generation
2-2-1. Circuit Operation
The sawtooth waveform generation circuit consists of as
shown in Fig. 11-4. When a trigger pulse enters pin 13, it is
differentiated in the waveform shape circuit and only the
falling part is detected by the trigger detection circuit, to the
waveform generation circuit is not susceptible to variations
of input pulse width.
The pulse generation circuit also works to fix the V ramp
voltage at a reference voltage when the trigger pulse enters,
so it can prevent the sawtooth wave start voltage from
variations by horizontal components, thus improving
interlacing characteristics.
5Vp
DC=0V
13
WAVEFORM
SHAPE
TRIGGER
DET.
PULSE
GAIN
V. RAMP
AGC
14
15
16
Q302
+
R329
Fig. 11-4
11-3
C321
C322
C323
2-3. V Output
and supplies a sawtooth waveform current to a deflection
yoke. Q3 turns on for first half of the scanning period
and allows a positive current to flow into the deflection
yoke (Q3 DY C306 R305 GND), and Q4 turns
on for last half of the scanning period and allows a
negative current to flow into the deflection yoke
(R305 C306 DY Q4). These operations are
shown in Fig. 11-5.
2-3-1. Circuit Operation
The V output circuit consists of a V driver circuit Q302,
Pump-up circuit and output circuit Q301, and external
circuit components.
(1) Q2 amplifies its input fed from pin 4 of Q301, Q3, Q4
output stage connected in a SEPP amplifies the current
+35V
D301
C308
50V
V3
D308
27V
Q301
6
3
GND
D309
Q3
V7
27V
7
GND
BIAS
CIRCUIT
V2
50V
2
Q2
Q4
4
R308
DY
+
C306
GND
Q3 ON
R305
GND
1
Q4 ON
Fig. 11-5 V output circuit
(2) In Fig. 11-6 (a), the power Vcc is expressed as a fixed
level, and the positive and negative current flowing
into the deflection yoke is a current (d) = current (b) +
(c) in Fig. 11-6, and the emitter voltage of Q3 and Q4
is expressed as (e).
(3) Q3 collector loss is i1 x Vce1 and the value is equal to
multiplication of Fig. 11-6 (b) and slanted section of
Fig. 11-6 (e), and Q4 collector loss is equal to
multiplication of Fig. 11-6 (c) and dotted section of
Fig. 11-6 (e).
Power Vcc
GND (b) Q3 Collector current i1
Q3
GND (c) Q4 Collector current i2
i1
Vce 1
Q4
GND (d) Deflection yoke current i1+i2
Q2
i2
Vp
Vcc
1/2 Vcc
GND
(a) Basic circuit
Fig. 11-6 Output stage operation waveform
11-4
(e)
basic operation is shown in Fig. 11-8.
(6) Since pin 7 of a transistor switch inside Q301 is
connected to the ground for the scanning period, the
power supply (pin 3) of the output stage shows a
voltage of (VCC-VF), and C308 is charged up to a
voltage of (VCC-VF--VR) for this period.
(7) First half of flyback period
Current flows into L462 D1 C308 D308 VCC
(+35V) GND R305 C306 L462+L463+L464
in this order, and the voltage across these is:
VP=VCC+VF+(VCC-VF-VR)+VF about 50V is
applied to pin 3. In this case, D301 is cut off.
(8) Last half of flyback period
Current flows into VCC switch D309 C308
Q301(pin3) Q3 L462+L463+L464 C306 R305
in this order, and a voltage of VP=VCC-VCE (sat)VF+(VCC-VF-VR)-VCE (sat), about 40V is applied
to pin 3.
(9) In this way, a power supply voltage of about 27V is
applied to the output stage for the scanning period and
about 50V for flyback period.
(4) To decrease the collector loss of Q3, the power supply
voltage is decreased during scanning period as shown
in Fig. 11-7, and VCE1 decreases and the collector loss
of Q3 also decreases.
Q3 Collector loss decreases
by amount of this area
Power supply
for flyback period (Vp)
Power supply
for scanning period
(Vcc)
Scanning period
Flyback period
Fig. 11-7 Output stage power supply voltage
(5) In this way, the circuit which switches power supply
circuit during scanning period and flyback period is
called a pump-up circuit. The purpose of the pump-up
circuit is to return the deflection yoke current rapidly
for a short period (within the flyback period) by
applying a high voltage for the flyback period. The
D301
D301
C308
C308
D308
D308
Q301
6
Q301
3
D309
6
3
D309
R308
7
Q3
VR
Switch
Switch
7
Q3
D1
D1
First half
L462+L463+L464
L462+L463+L464
2
Q4
2
+
C306
R308
Q4
+
C306
R305
R305
Last half
(a) Scanning period
(b) Flyback period
Fig. 11-8
11-5
2-4. V Linearity Characteristic Correction
2-4-1. S-character Correction
(Up-and Down-ward Extension Correction)
A parabola component developed across C306 is integrated
by R306 and C305, and the voltage is applied to pin 6 of
Q302 to perform S-character correction.
2-4-2. Up-and Down-ward Linearity Balance
A voltage developed at pin 2 of Q301 is divided with
resistors R307 and R303, and the voltage is applied to pin
6 of Q301 to improve the linearity balance characteristic.
Moreover, the S-character correction, up- and down-ward
balance correction, and M-character correction are also
performed through the bus control.
11-6
3. PROTECTION CIRCUIT FOR V
DEFLECTION STOP
Q301
2
DPC CIRCUIT
L462+L463+L464
VERTICAL DEFLECTION COILS
Q350
C350
V-NF
9V
R354
R352
C306
R305
0.82
12V
D350
Q351
D354
BLANKING
CIRCUIT
Q353
R350
D353
V-STOP
Fig. 11-9
When the deflection current is not supplied to the deflection
coils, one horizontal line appears on the screen. If this
condition is not continued for a long time, no trouble will
occur in a conventional TV. But in the projection TV, all the
electron beams are directly concentrated at the fluorescent
screen because of no shadow mask used, and burns out the
screen instantly.
To prevent this, the stop of the V deflection is detected when
the horizontal one line occurs, and the video signals are
blanked out so that the electron beams are not emitted.
When the V deflection circuit is operating normally, a
sawtooth wave voltage is obtained across (R305), so Q350
repeats on-off operation in cycle of V sync. In this case, the
collector voltage of Q35 is set to develop less than (12V-VBE
(Q351)) with R352 and C350 as shown in Fig. 4-8.
Accordingly, Q351 and Q353 are continuously turned on. As
a result, diode D354 is turned off, giving no influence on the
blanking operation.
Next, when the V deflection stops, the voltage across (R305)
does not develop, so Q350 turns off, and both the Q351 and
Q353 are turned off. Then, the picture blanking terminal pin
13 of ICA05 is set to high through R354 and D354 connected
to 90V power line, BLANKING CIRCUIT ON thus cutting
off the projection tubes.
Volttage Across
R305
Q340 VBE
Q350 BASE
12V-VBE (Q341)
Q351 Collector
Fig. 11-10
11-7
3-1. +35V Over Current Protection Circuit
The over current protection circuit cuts off the power supply
relay when it detects abnormal current increased in the +35V
power line due to failure of the vertical deflection circuit.
3-1-1. Theory of operation
Fig. 11-11 shows the circuit diagram of the over current
protection circuit. When the load current of the +35V line
increases, the voltage across a resistor of T370 will also
increase. When the voltage increases across R370. and the
voltage developed across R371 becomes higher than the Vbs
of Q370, Q370 turns on and a voltage develops across R374
due to the collector current flowing. When this voltage
increases to a value higher than about 13V, Z801 operates,
thus cutting off the power relay. When the circuit operates,
a power LED provided will turn on and off in red.
C303
R370
R327
+35V
C310
R372
D302
FBT
pin 6
R371
C370
D421
UZ22BSD
Q370
2SA933SQ
D370
UZ11BSB
R373
R375
C371
R374
Fig. 11-11
11-8
To pin 14 (GATE)
of Z801
SECTION XII
HORIZONTAL DEFLECTION CIRCUIT
12-1
1. OUTLINE
The H deflection circuit works to deflect a beam from left to
right by flowing a sawtooth waveform of 15.734 kHz into the
DY H deflection coil.
2. HORIZONTAL DRIVE CIRCUIT
The H drive circuit works to start the H output circuit by
applying HVCC (Q501 DEF power source) to pin 22 of Q501
(TA1222N) and a bias to the H drive transistor Q402 at the
main power on.
2-1. Theory of Operation
(1) When the power switch is on, the main power supply of
125V starts to rise. At the same time, AF power supply
25V also rises.
(2) With 25V line risen, Q430 base voltage which is created
by dividing the audio power with R433 and D430 also
rises. Then, the transistor Q430 turns on and the HVCC
is applied from the audio power line through R432 and
D431 to pin 22 of Q501.
R432
Q430
D431
Q501
R433
D430
BB81
81
81
BB80
SIGNAL
22 H Vcc
L400
C431
Fig. 12-1 H drive circuit block diagram
12-2
C430
3. BASIC OPERATION OF HORIZONTAL
DRIVE
A sufficient current must flow into base of the horizontal
output transistor to rapidly make it into a saturated (ON)
condition or a cut off (OFF) condition. For this purpose, a
drive amplifier is provided between the oscillator circuit and
the output circuit to amplify and to waveshape the pulse
voltage.
turn off the transistor, a sufficiently high, reverse voltage
must be applied to the base.
(3) When the transistor is on (collector current is maximum)
condition with the sufficiently high forward voltage
applied to the base, the transistor can not be turned off
immediately, if a reverse base bias is applied to the base
because minority carriers storaged in the base can not be
reduced to zero instantly. That is, a reverse current
flows through an external circuit and gradually reduces
to zero. The time lag required for the base current to
disappear is called a storage time and falling time.
(4) To shorten the storage time and the falling time, a
sufficiently high reverse bias voltage must be applied to
allow a heavy reverse current to flow. This operation
also stabilizes operation of the horizontal output
transistor.
3-1. Theory of Operation
(1) The horizontal drive circuit works as a so called switching
circuit which applies a pulse voltage to the output
transistor base and makes the transistor on when the
voltage swings in forward direction and off in reverse
direction.
(2) To turn on the output transistor completely and to make
the internal impedance low, a sufficiently high, forward
drive voltage must be applied to the base and heavy base
current ib must be flown. On the contrary, to completely
On period
OFF period
+
t Input waveform (b)
0
+
Forward
current
ib
t Base current (c)
0
V
Reverse
current
-
Falling
time
(a)
Storage
time
Fig. 12-2
12-3
3-2. Drive System
3-2-1. ON drive system
When the drive transistor is on, the horizontal output transistor
also turns on.
3-2-2. OFF drive system
When the drive transistor is on, the horizontal output transistor
is off.
Merit:
• Energy balance between on and off periods of the drive
circuit is better, and the circuit can be simplified.
• Reverse base current of the horizontal output transistor
can be controlled easily.
Merit:
• The base current can be precisely controlled without
being affected by variation of pulse width which is
caused by the horizontal oscillator circuit and the drive
circuit.
Demerit:
• Base-emitter forward current flowing into the horizontal
output transistor is susceptible to on-period variation of
the drive transistor.
Demerit:
• It is difficult to flow a reverse bias current to the horizontal
output transistor to eliminate its storage carrier for transient
period of on to off period for the horizontal output
transistor.
H output
H output
H driver
H driver
H OSC
H OSC
ON
(OFF)
+B
ON
(OFF)
ON
(OFF)
+B
Fig. 12-4
Fig. 12-3
12-4
ON
(OFF)
3-3. Circuit Description
In the N5SS chassis, the off drive system is employed.
(1) When Q1 inside Q501 is turned on, Q402 base is
pin 22 of Q501 (H.
forward biased through 9 V
VCC) pin 23 of Q501 (H. Out) R411/R410 resistor
divider, and then, Q402 collector current flows through
125V R416 T401. In this case, the H output
transistor Q404 turns on with the base-emitter reverse
biased because of the off drive system employed.
(2) On the contrary, when Q1 inside IC501 is off (pin 8 is
0V), base-emitter bias of Q402 becomes 0V and Q402
turns off, and a collector pulse as shown in Fig. 12-5
develops at the collector.
The voltage is stepped down and Q404 is forward
biased with this voltage, thus turning on Q404.
(3) In this way, by stepping down the voltage developed at
primary winding of the drive transformer and by applying
it to Q404, a sufficient base current flows into Q404
base, thereby switching the Q404.
Q501
22
H. Vcc
T401
H drive
transistor
C417
C431
1
3
R415
Q1
R411
23
2
R410
4
Q404
H output
transistor
C413
Q402
H drive
transistor
V1
+
V2
R416
0V
C416
+125V
9V
VCP
0V
Q402
OFF
Fig. 12-5
12-5
Q402
ON
4. HORIZONTAL OUTPUT CIRCUIT
The horizontal output circuit applies a 15.734 kHz sawtooth
wave current to the deflection coil with mutual action of the
horizontal output transistor and the damper diode, and deflects
the electron beam from left to right in horizontal direction.
HV
10
5
T461
FBT
2
S-charactor
capacitor
3
Q404
H output
(With damper diode)
T401
H drive
transformer
IC501
R415
Deflection yoke
(H coil)
8
1
C440
L462 L463
C343
C444
H. out
C418
TP-33
Q402
H drive
D461
C423
R441
BB81
Q1
23
H
linearity
coil
C463
83
R411
R410
C417
C467
D443
To High Voltage
Regulator Circuit
+
R416
Resonat
capacitor
C464
+
To DPC output
SIGNAL
PCB
DEF/POWER PCB
L441
L461
C413
C416
125V
Diode modulator circuit
Fig. 12-6
12-6
L464
D444
4-1. Theory of Operation
4-1-1. Operation of Basic Circuit
(1) To perform the horizontal scanning, a 15.734 kHz
sawtooth wave current must be flown into the horizontal
deflection coil. Theoretically speaking, this operation
can be made with the circuit shown in Fig. 12-7 a and b.
(2) As the switching operation of the circuit can be replaced
with switching operation of a transistor and a diode, the
basic circuit of the horizontal output can be expressed
by the circuit shown in Fig. 12-7 a. That is, the transistor
can be turned on or off by applying a pulse across the
base emitter. A forward switching current flows for onperiod, and a reverse switching current flows through
the diode for off-period. This switching is automatically
carried out. The diode used for this purpose is called a
damper diode.
a
Description of the basic circuit
1. t1~t2:
A positive pulse is applied to base of the output transistor
from the drive circuit, and a forward base current is flowing.
The output transistor is turned on in sufficient saturation
area. As a result, the collector voltage is almost equal to the
ground voltage and the deflection current increases from
zero to a value in proportionally. (The current reaches
maximum at t2, and a right half of picture is scanned up to this
period.)
2. t2:
The base drive voltage rapidly changes to negative at t2 and
the base current becomes zero. The output transistor turns
off, collector current reduces to zero, and the deflection
current stops to increase.
3. t2~t3:
The drive voltage turns off at t2, but the deflection current
can not reduce to zero immediately because of inherent
nature of the coil and continues to flow, gradually decreasing
by charging the resonant capacitor C0. At the same time, the
capacitor voltage or the collector voltage is gradually
increases, and reaches maximum voltage when the deflection
current reaches zero at t3. Under this condition, all electromagnetic energy in the deflection coil at t2 is transferred to
the resonant capacitor in a form of electrostatic energy.
H output basic circuit
H output
transistor
D
Damper
diode
Co
L
Deflection
yoke
Resonant
capacitor
4. t3~t4:
Since the charged energy in the resonant capacitor discharges
through the deflection coil, the deflection current increases
in reverse direction, and voltage at the capacitor gradually
reduces. That is, the electrostatic energy in the resonant
capacitor is converted into a electromagnetic energy in this
process.
Vcc
b
H output equivalent circuit
SW1
SW2
Co
L
5. t4:
When the discharge is completed, the voltage reduces to
zero, and the deflection current reaches maximum value in
reverse direction. The t2~t4 is the horizontal flyback period,
and the electron beam is returned from right end to the left
end on the screen by the deflection current stated above. The
operation for this period is equivalent to a half cycle of the
resonant phenomenon with L and C0, and the flyback period
is determined by L and C0.
Vcc
Fig. 12-7
12-7
t1
6. t4~t6:
For this period. C0 is charged with the deflection current
having opposite polarity to that of the deflection current
stated in "3.", and when the resonant capacitor voltage
exceeds VCC, the damper diode D conducts. The deflection
current decreases along to an exponential function
(approximately linear) curve and reaches zero at t6. Here,
operation returns to the state described under "1.", and the
one period of the horizontal scanning completes. For this
period a left half of the screen is scanned.
In this way, in the horizontal deflection scanning, a current
flowing through the damper diode scans the left half of the
screen; the current developed by the horizontal output
transistor scans the right half of the screen; and for the
flyback period, both the damper diode and the output transistor
are cut off and the oscillation current of the circuit is used.
Using the oscillation current improves efficiency of the
circuit. That is, about a half of deflection current (one fourth
in terms of power) is sufficient for the horizontal output
transistor.
A
TR
base voltage
0
B
TR
base current
0
C
TR
collector
current
D
D
damper
current (SW2)
E
Switch
current
(TR, SW1)
F
G
H
t2 t3 t4 t5
0
0
0
Resonant
capacitor
current (Co)
0
Deflection
current (Lo)
0
TR
collector
voltage
0
Fig. 12-8
12-8
t6
Amplitude Correction
To vary horizontal amplitude, it is necessary to vary a
sawtooth wave current flowing into the deflection coil.
These are two methods to vary the current; a method which
varies LH by connecting a variable inductance L in series with
the deflection yoke, and a method which varies power supply
voltage (across S-character capacitor) for the deflection
yoke.
As the DPC circuits is used in the this chassis, the later
method which varies the deflection yoke power supply
voltage by modifying the bus data is used.
t2
t1
q
q
2
t1
q
q
t2 = t1
q 2< q 1
1
(a) S-character correction
4-1-2. Linearity Correction (LIN)
(1) S-curve Correction (S Capacitor)
Pictures are expanded at left and right ends of the screen even
if a sawtooth current with good linearity flows in the deflection
coil when deflection angle of a picture tube increases. This is
because projected image sizes on the screen are different at
screen center area and the circumference area as shown in
Fig. 12-9. To suppress this expansion at the screen
circumference, it is necessary to set the deflection angle q1
to a large value (rapidly deflecting the electron beam) at the
screen center area, and to set the deflection angle q2 to a
small value (scanning the electron beam slowly) at the
circumference area as shown in Fig. 12-9.
In the horizontal output circuit shown in Fig. 12-10, capacitor
CS connected in series with the deflection coil LH is to block
DC current. By properly selecting the value of CS and by
generating a parabolic voltage developed by integrating the
deflection coild current across the S capacitor, and by varying
the deflection yoke voltage with the voltage, the scanning
speed is decreased at beginning and end of the scanning, and
increased at center area of the screen. The S curve correction
is carried out in this way, thereby obtaining pictures with
good linearity.
t2
2
1
(b)
Fig. 12-9
Cs
TR
D
Co
LH
Deflection coil
Vcc
(a) H output circuit
(b) Sawtooth wave current
(c) Voltage across LH
Fast deflection
Slow deflection
(d) Synthesized current
Fig. 12-10
12-9
t2 > t1
q 2= q 1
(2) Left-right Asymmetrical Correction (LIN coil)
In the circuit shown in Fig. 12-11 a, the deflection coil current
iH does not flow straight as shown by a dotted line in the
figure b if the linearity coil does not exist, by flows as shown
by the solid line because of effect of the diode for a first
scanning (screen left side) and effect of resistance of the
deflection coil for later half period of scanning (screen right
side). That is, the deflection current becomes a sawtooth
current with bad linearity, resulting in reproducing of
asymmetrical pictures at left and right sides of the screen (left
side expanded, right side compressed).
When a horizontal linearity oil L1 with a current characteristic
as shown in figure c is used, left side picture will be compressed
and right side picture will be expanded because the inductance
is high at the left side on the screen and low at the right side.
The left-right asymmetrical correction is carried out in this
way, and pictures with good linearity in total are obtained.
(a)
LH
TR
D
FBT
LH
Deflection
coil
Co
TR
D
Co
LI
L
iH
Li
Cs
Vcc
C
Cs
S-character
capacitor
(b) Deflection coil current
Deflection coil current
(iH)
(b) Sawtooth wave current
Resistance of LH
Characteristic of D
0
(Left)
Fig. 12-12
(Right)
(c) Linearity coil characteristic
Linearity coil characteristic
Inductance
(m H)
(Left)
(Right)
Current (A)
Fig. 12-11 Linearity coil
12-10
4-2. White Peak Bending Correction Circuit
4-2-1. Outline
White peak area in screen picture may sometimes cause
bending in picture. See figure below.
In TP48E60 series, correction signal which consists of video
signal and video ripple in video output circuit power supply
200V is input to pin 24 (Bending correction terminal) of
Q501. This corrects white peak bending.
4-2-2. Operation theory
Fig. 12-13 shows circuit diagram. From R, G and B output
(pins 41, 42 and 43 of Q501), video signal is taken in the
dividing ratio of resistor R375 and R378. After that, it suffers
DC cut by C360 and integration by R369 and C415, then is
input to pin 24 of Q501. On the other hand, video ripple in
video output circuit power supply 200V suffers DC cut by
C475, and is inverted in Q470, then input to pin 24 of Q501
via C481. Pin 24 of Q501 is a bending correction terminal.
The voltage which is applied to this terminal, controls phase
of video signal to correct white peak bending.
9V
Q501
R375
Q362
Q361
R367
R360
R OUT 43
R364
G OUT 42
Q360
R365
R378
B OUT 41
R368
R366
24
EHT
Bending correction
terminal
R369
C360
Integration
C415
BB91
93
Receiving Board
Power, Def board
9V
R481
200V
R483
D406
R478
C481 Inversion
3 T416
C475
Q470
D470
R482
R484
White peak
Bending by white peak
Fig. 12-13 White peak bending correction circuit
12-11
D474
C466
4-3. H Blanking
4-3-1. Outline
The H blanking circuit applies a blanking precisely for the
horizontal flyback period so that undesirable pictures folding
does not appear at screen ends.
This unit allows the users to adjust an horizontal amplitude
adjustment, so, picture quality at screen ends will be improved.
This is one of the purposes of the blanking circuit.
4-3-2. Theory of Operation
The H blanking circuit determines the flyback period precisely
from the AFC pulse in the FBT and applies the period to
emitter of the video output stage transistor on the CRT-D PC
board.
4-3-3. Circuit Operation
As can be seen from Fig. 12-14, the flyback period of the
AFC pulse in the FBT starts at a negative side from 0V. To
detects this, the DC component is cut with C493. This is,
C493 is always charged through D487 with a negative side
(about -17V) of the AFC pulse. As a result, a voltage at point
A in the waveform rises from the ground level. This waveform
is sliced in a circuit (R410, C492, D486) to detect the flyback
period. Thus obtained voltage is applied to Q901, Q903, and
Q905 through D912 ~ D914 and cuts off them thereby
blanking the resters.
Q487
ON period
D486
Slice level
0V
Approx.
-17V
Waveform at
point
AFC Pulse
Fig. 12-14
Q901
+27V
Q903
D912
Q905
D913
Point A
T461 (FBT)
AFC
Q487
C493
7
R405
164
P903
CRT-D DCB
164
R410
R409
D914
R906
C492
P405
D486
R417
Deflection/Power PCB
Q489
D487
C449
AFC
R438
R445
Q488
V blanking
D441
Fig. 12-15
12-12
4-4. 200V Low Voltage Protection
4-4-1. Outline
CPT. To prevents this, a 200V low voltage protection circuit
is provided.
V circuit
Defletion circuit
CRT-D Circuit
1
1
2
2
-12V
P310B
P310A
P405
200V
4-4-2. Theory of Operation
Fig. 12-16 shows a connection diagram.
Under a normal condition Q340 is always on because of
about 210V supplied from the 200V line. Accordingly Q340
collector is kept at about 6.2V or the zener voltage of D341
and Q341 is turned off.
If some abnormality occurs and 200V line voltage lowers by
less than about 160V. Q340 turns off and its collector voltage
rises. So Q341 turns on. With Q341 turned on the voltage at
pin 14 of Z801 (expander) exceeds a threshold voltage and
pin 16 of Z80 is high level and makes the power relay turn off.
R389
R390
Q340
R347
VL
VL
VQ
VQ
Q341
D340
R391
D341 R392
Z801
14 GATE
PROTECTOR
16
Fig. 12-16
12-13
C340
5. HIGH VOLTAGE GENERATION
CIRCUIT
The high voltage generation circuit develops an anode voltage
for the picture tube, focus, screen, CRT heater, video output
(210V) and so on by stepping up the pulse voltage developed
for flyback period of the horizontal output circuit with the
FBT, and supplies the power to various circuit.
5-1. Theory of Operation
AFC
blanking
9
Heater
+12V
R448
C303
Auxiliary
winding
CRT
anode
10
+27V
4
C447
D408
D302
C310
7
R327
Focus Pack
6
C460
D460
R469
-27.5V
5
D406
R443
+210V
Primary
winding
3
C446
+125V
2
R444
C448
1
ABL
Q404
T401
C463
H deflection coil
L462/L463/L464
L441
1000VP-P
R441
0
C423
1H
(15.75KHz)
Fig. 12-17
12-14
5-1-1. +210V
For the flyback period, pulses are stacked up to DC +125V
with FBT, and the voltage is rectified by D406 and filtered by
C446.
+125V
5-1-2. +35V, 12V
Pin 4 of the FBT is grounded and the shaded area of negative
pulse developed for opposite period of the flyback period is
rectified, thus developing better regulation power supply.
0
Fig. 12-18
5-1-3. -27V
As a power for the DPC circuit, a negative pulse signal is
rectified by D460 and filtered with C460, thus developing the
-27V.
0
10
5-1-4. High voltage
Singular rectification system which uses a harmonics nonresonant type FBT is employed and a better high voltage
regulation is obtained, so amplitude variation of pictures
becomes low.
4
7 +35V
0
6 For +12V
2
0
1
Fig. 12-19
G
F
Picture
tube anode
Picture
tube capacitor
Primary
D
E
F
EH
D
C
Stacked
pulse of
4 block
C
EO
B
Auxiliary
G
Pulse
E
B
A
A
1H
15.735KHz
ABL
Fig. 12-20
12-15
5-2. Operation Theory of the Harmonic Non-Resonant
System and Tuned Waveforms
The high voltage coil is of film multi-layer winding type and
the coils are isolated into seven blocks. Each block is connected
through a diode.
The basic operation is described in the case of 4 blocks
construction for simplification. Positive or negative pulse
determined by stray capacitance of each coil develops at
terminal points ( , , , , , F , G ) of each coil
as shown in Fig. 12-20, and these pulses are stacked as
shown, thus developing the high voltage.
Moreover, a capacitance between the internal and external
coatings of the picture tube works as a smoothing capacitor.
Focus voltage is obtained at point EO.
The FBT is turned to a harmonic of 15 times the fundamental
frequency, and the turned waveform is shown in Fig. 12-21.
Flyback
pulse
63.5m s
AC
0
AC
0
11m s
Reference
wave
45 KHz
20m s
1
1
=
= 45KHz
22m s 22x10-5
Becomes 45 KHz x 15 = 675KHz
this is determined by coil inductance capacitance and
stray of FBT.
Harmonics
15 times
675 KHz
Tuned
waveform
(In case of 3X)
Hight
voltage
Focus
current
(In case of 15X)
E
E
Picture tube current
In case of 15 times the harmonics as compared with
3 times the harmonics, average conduction peiod of
the high voltage diode is wider.
As a result, high voltage variations are suppressed.
AC
0
Fig. 12-21 Tuned waveforms
12-16
6. HIGH VOLTAGE CIRCUIT
6-1. High Voltage Regulator
6-1-1. Outline
Generally, four kinds of methods exist to stabilize a high
voltage in high voltage output circuits using the FBT:
(1) Stabilization by varying the power supply voltage.
(2) Stabilization by varying L value with a saturable
reactance connected in series with the primary winding
of the FBT.
(3) Stabilization by varying equivalent capacitance of the
resonant capacitor C0.
(4) Stabilization by superimposing a DC or pulse (this
varies the high voltage) on a lower voltage side of the
high voltage winding of the FBT.
Hotizonal
output
In this unit, pulse transformer is eliminated and the regulator
circuit using the method (3) is employed. The block diagram
is shown in Fig. 12-22.
ANODE
FBT
DY
125V
PW output
-27V
High voltage Reg.
V.
Ref.
Fig. 12-22 Basic circuit for high voltage regulator emplyed in the unit
12-17
6-1-2. Theory of Operation
Fig 12-23 shows a basic circuit of the high voltage regulator
used in the unit.
The high voltage regulator circuit splits a resonant capacitor
C0 to C1 and C2. thereby dividing the collector voltage (VCP)
of the H output transistor with C1 and C2.
Here, assume each voltage developed across C1 and C2 as
VCP1 and VCP1, respectively,
VCP1 =
Horizontal
output
VCP =
+B
CS
C2
VCP
C1+C2
D1
C2
VCP2 =
FBT
LP
C1 LH
C2
VCP
C1+C2
B
D2
C3
Q1
C2
VCP2
C1+C2
each relation can be expressed by the above equations
~ .
The VCP2 developed across C2 is DC-clamped with a diode
D1 and the resultant voltage is smoothed with a diode D2 and
a capacitor C3. Thus processed voltage is obtained at the
point . This voltage is used to provide a base current for the
transistor Q1 or to flow the collector current. The voltage at
the point decreases with the circuit impedance and finally
lowers up to a VCE saturation voltage of Q1.
Then, VCP2 is not clamped by D2 with the voltage at the point
B. Since the VCP is expressed as a sum of VCP1 and VCP2 as
shown by equation , VCP decreases by amount the VCP2 is
decreased. This varies the high voltage.
Q1 collector current is controlled by Q1 base current which
is an output of the comparison inverted amplifier. That is, the
Q1 base current is controlled by a voltage obtained by
comparing a detection voltage of the top breeder of the FBT
(9.1V) and a DC voltage of 9V.
High voltage
Reg.
output amp
Fig. 12-23
VCP = VCP1 + VCP2
VCP 1
VCP 2..
Fig. 12-24
12-18
6-1-3. Actual
Fig 12-25 shows the actual circuit used in the unit.
A resonant capacitor C0 is also split into two capacitors C443
and C444 in this circuit. The high voltage regulator cirucits
is structured by splitting the C443 to two capacitors of C443
and C448.
Here, assume a high voltage increases and the detection
voltage ED´ obtained by dividing the high voltage also
increases in proportional to the high voltage. This makes the
voltage ED increase at pin 7. (The voltage is impedance
transformed by a voltage follower circuit consisting of op
amplifier Q483 at pin 7.)
The voltage ED and a 9V reference voltage developed by a 3terminal regulator Q420 are compared. When the ED increases,
the voltage at pin 2 of Q483 differential amplifier also
increases, and the base current IB of the high voltage
transistor Q480 increases.
As a result, Q480 collector current increases and Q480
collector voltage (at the point ) decreases. Then, a peak
value of VCP2 across C418 is clamped by the diode D443 at
the collector voltage lowered, and the collector voltage VCP
of Q404 (H output transistor) obtained as a sum of the voltage
VCP1 across C443 and VCP2 across L418 decreases. Then, the
high voltage also decreases.
When the high voltage lowers, the corrective operation is
carried out in reverse order.
* Resustors R451, R452, R453 and R455 are used to correct
undersirable influence (H amplitude increase at minimum
IH) by the H amplidude regulator.
FBT
Horizontal
output
Q404
C443
C440
L462
C444
EH
-27V
CS
R460
125V
R466
R435
C467
D461
Q462
R461/R469
L461
R463
R455
ED'
Q460
C482
Q483
C464
R454
D443
ED
B
R451
6
8
R453
7
R452
R489
D444
C418
C419
Q480
R434
4
2
R431
R492
R450
3
R488
R490
Q420
C483
R494
R439
R487
Fig. 12-25 Actual high voltage regulator circuit
12-19
9V
7. X-RAY PROTECTION CIRCUIT
7-1. Outline
In case picture tube using high voltage, when high voltage
rises abnormally due to components failure and circuit
malfunction, there is possible danger that X-RAY leakage
increases to affect human body. To prevent it, X-RAY
protection circuit is equipped.
7-2. Operation
Figure 10-18 shows the circuit diagram. Supposing high
voltage rises abnormally due to some reason, pulse at pin 9
of T461 also rises, and detection voltage Eb rectified by
D471 and C471 in X-RAY protection circuit rises. When Eb
rises, emitter voltage of Tr10 divided by R25 and R26 in
protector module becomes higher than [zener voltage (6.2V)
of ZD6 + Tr10 VBE ]. This causes Tr10 turns on to supply
base current to Tr9. Then Tr9 turns on. By this Tr6 and Tr6
turn on to make ON/OFF pulse at pin 7of QA01 in low level,
QB30 and Q843 turns off, then relay SR81 turns off. Tr6 and
Tr7 are in thyristor-connection, and 5V of power holds
protection operation until main power switch is turned off.
During circuit operation, power LED near main power
switch blinks turn on and off in red.
Caution : To restart TV set, repair failure first.
5V
Z801
15
12V
MICOM
QA01#7
R9
R10
R25
Tr10
Tr7
Tr9
T461
R472
9
D471
RB30
R21
RELAY
SR81
Tr6
R26
R20
16
Tr5
R12
C471
R22
D3
Q843
ED
13
ZD6
C1
QB30
R11
12
+
C474
Fig. 12-26 X-RAY protection circuit
12-20
8. OVER CURRENT PROTECTION
CIRCUIT
8-1. Outline
If main power (125V) current increases abnormally due to
components failure, there is possible danger of the secondary
damage like failure getting involved in other part failure, and
abnormal heating. To prevent this, over current protection
circuit is equipped, which detects current of main B line to
turn off power relay in abnormal situation.
8-2. Operation
Fig. 12-27 shows over current protection circuit. When the
current of main B line increases abnormally due to the
shortage in load of main B line, voltage drop arises across
R470. By this voltage drop, when base-emitter voltage of Tr
8 in protector module (Z801) becomes appprox. 0.7V or
more, Tr 8 turns on, and the voltage by divided ratio of R15
and R16 is applied to cathode of ZD4. When this voltage
becomes higher than zener voltage of ZD4, ZD4 turns on to
supply base current to base of Tr 6 via R14. This causes Tr 5
ON and voltage at pin 16 of Z801 becomes Low. Therefore,
QB30 and Q843 turns off to set SR81 OFF. Tr 6 and Tr 7 in
Z801 are in thyristor- connection, and power 5V-1 supplied
at pin 15 keeps protection operation for standby power until
main power switch is turned off. During circuit operation,
power LED near main power switch blinks in red.
Caution : To restart TV set, repair failure first.
F470
R470
To T461
MAIN B
R471
R479
5V
C472
15
MICON
QA01#7
2
R9
ZD4
RB30
R10
RELAY
SR81
16
R16
Tr7
Tr8
R14
Q843
1
R15
D1
Tr6
QB30
R12
C1
Tr5
R11
Z801
PROTECTOR MODULE
17
Fig. 12-27 Over current protection circuit
12-21
NOTES
12-22
SECTION XIII
DEFLECTION DISTORTION
CORRECTION CIRCUIT
(DPC Circuit)
13-1
1. DEFLECTION DISTORTION
CORRECTION IC (TA8859P)
(3)
(4)
(5)
(6)
(7)
(8)
1-1. Outline
The deflection distortion correction IC (TA8859AP), in
combination with a V/C/D IC (TA1222N) which has a V
pulse output, performs correction for various deflection
distortions and V output under I2C bus control. All the I2C
bus controls are carried out by a microcomputer and can be
controlled with the remote control.
(9)
1-2. Functions and Features
The IC has functions of V RAMP voltage generation, V
amplitude automatic switching (50/60 Hz), V linearity
correction, V amplification, EHT correction, side pincushion
correction, I2C bus interface, etc. and controls following
items through the I2C bus lines.
(1) V amplitude
(2) V linearity
(10)
(11)
(12)
V S-character correction
V picture position (neutral voltage setting)
V M-character correction
V EHT correction
H amplitude
L and R pin-cushion distortion correction I (entire
area)
L and R pin-cushion distortion correction II (corner
portions at top and bottom)
H trapezoid distortion correction
H EHT correction
V AGC time constant switching
1-3. Block Diagram
Fig. 13-1 shows a block diagram of the basic circuit.
+12V
V. Trigger-in
13
Waveform
Shape
Trigger
Det
V. M-Character
Correction
14
15
16
Puise
Gen.
V. Rame
AGC
V. S-Character
Correction
V. Linearity
Correction
(Bus Control Signal)
SDA SCL
9
3
V. AGC Time
Constant SW
Control Through
Bus
H. Trapezoid Distortion
Correction
L-R Pincushion
Distortion Correction I
L-R Pincushion
Distortion Correction II
(Top & Bottom Comer Section)
V. Amplitude
Adj.
10
5
Logic
V. Screen
Position
12
V. EHT
Correction
H.EHT
Input
H.EHT
Corrction
H. Amplitude
Adj.
8
1
4
EHT INPUT
EW Feedback
6
V Drive V. Feedback
2 EW-Drive
Fig. 13-1
13-2
2. DIODE MODULATOR CIRCUIT
Cr, as shown in Fig. 13-3, are applied to the primary
winding, the high voltage of the FBT is also constant.
Fig. 13-2 shows a basic circuit of the diode modulator used
in the N5SS chassis.
A key point in the modulation circuit shown in Fig. 13-2 is
the development of a negative pulse at point B.
In this circuit, a current loop of the resonant circuit for
flyback period is shown by an arrow, and the energy stored
in LDY is transferred to resonant capacitors Cr, Crm in
passing through Cr, Crm, Cs when the scanning completes.
As a result, a positive, horizontal pulse as shown in Fig.
13-3
will appear at Cr, and the current flows into Crm
with the direction as shown. Then a pulse as shown in Fig.
13-3
develops at the point B.
On the other hand, since constant amplitude pulses across
When the negative pulse developed at point B is integrated
with Lm and Csm, the average value appears at Csm as a
negative voltage.
By modulating this voltage to have a parabolic curve with
Q460, a waveform of Vm is obtained as shown in Fig. 134. As a result, the voltage Vs which is the sum of the power
supply voltage VB and Vm, is applied across the S-curve
capacitor Cs. Vs becomes a power source for the deflection
yoke, and the modulated parabolic waveform, as shown in
, is applied to the horizontal deflection yoke
Fig. 13-3
and corrects the left-right pin-cushion distortion.
A
FBT
LDY
H
OUT
DD
Cr
VB
Cs Vs
0
a) Waveform at point A
B Lm
0
Q460 Vm
DM
Crm
Csm
b) Waveform at point B
Fig. 13-2
Fig. 13-3
VB
VS
0
Fig. 13-4
13-3
3. ACTUAL CIRCUIT
In the actual circuit, the resonant capacitor is split into two
as shown in Fig. 13-7. One, C440, is inserted between the
collector of the H. OUT transistor and ground. The second
one, C444, is inserted between the collector and emitter. In
Fig. 13-5, C440 is expressed as C1 and C444 as C2, and the
resonant current path for the flyback period is shown by
arrows.
FBT
IP2
IP1
C1
IH
In a conventional circuit, when the brightness of a picture
tube varies, high voltage current and high voltage also vary.
As a result, horizontal amplitude is affected.
LDY
H.
OUT
IY1
IY
CS
IP
VS
C2
However, in this circuit, the horizontal amplitude variation
can be suppressed to near zero if the high voltage current
varies with variation of the high voltage.
VB
Lm
C3
IP2
Csm
IY1
When the scanning period completes, the energy stored in
the deflection yoke LDY is transferred to the resonant
capacitor in a form of current Iy. In this case, the current is
split into two; Iy1 passing through C1, C3 and Iy2 passing
through C2. In the same way, the energy stored in the
primary winding of the FBT is transferred to the resonant
capacitor in the form of Ip. In this case, the current (path) is
also split into two; Ip1 passing through C1 and Ip2 passing
through C2, C3. Concequently, the current differences
between Iy1 and Ip2 (Iy1-Ip2) passes through C3.
Fig. 13-5
When the high voltage current IH reduces with a dark
picture, the current Ip in the primary circuit decreases, so
Ip1 and Ip2 also decrease. However, a current flowing into
(Iy1-Ip2) increases as Ip2 decreases. As a result, the pulse
developing at the point B increases and the voltage Vm at
Csm also increases as shown in Fig. 13-8. That is, when a
dark picture appears, the voltage across S-curve capacitor
Cs increases as shown in Fig. 13-8, the high voltage rises,
and the horizontal amplitude is going to decrease. But, as Vs
increases, the deflection yoke current increases and this
works to increase the horizontal amplitude. Accordingly, if
the brightness of a picture changes, the horizontal amplitude
is maintained at a constant value.
VB
VS
0
Fig. 13-6
13-4
Vm
3-1. Basic Operation and Current Path
3-1-1. Later Half Scanning Period
3-1-2. First Half Scanning Period
When the base drive current decreases and the H. OUT
transistor is turned off, each of the energies stored in LDY,
Lm, Lp of FTB is transferred to C1, C2 and C3, respectively,
and the resonant current becomes zero at a center of the
flyback period. Then, VA and VB pulses show a maximum
amplitude.
When the power is turned on, the power supply voltage VB
is applied to Cs and Csm, and the Cs acts as a power source
for a later half of the scanning period for which the H. OUT
transistor is turned on, and the deflection current Iy flows in
the path as shown below
VA
FBT
LDY
VA
lP
IY
H.OUT
FBT
+
LDY
Cs
IP1
VB
VB
C2
IP2
LM
IM
C1
lP
IY
IY2
Cs
IDC
DM
+
VB
VB
CSM
IM
LM
IDC
CSM
Fig. 13-7
Fig. 13-9
Voltage & current waveform in H period.
IY
VA
IM
0
IY
0
VA
0
IM
0
IDC
VB
0
0
0
IDC
VB
0
Fig. 13-8
C1
C2
0
C3
0
C1: IY1+IP1
C2: IY2+IP2
C3: IP2-IY1-IM
Fig. 13-10
13-5
3-1-3. Later Half of Flyback Period
All energy in the coil has been transferred to the resonant
capacitors at the center of the flyback period, and the
voltage shows the maximum value. However, during next
half of the flyback period, the energy of the resonat capacitor
is discharged as a reverse current through respective coil.
When the discharge has been completed, VA and VB
becomes zero, and the deflection current in reverse direction
becomes the maximum.
3-1-4. First Half of Scanning Period
When the flyback period completes, the damper diode DD
and the modulation diode DM turn on, and the Iy and Im
proportionally decrease from the maximum value to zero.
The H. OUT transistor is turned on just preceding at the
center of the scanning period, and repeats the steps 3-1-1
through 3-1-4 stated above.
VA
VA
L.O.P.T
LDY
LDY
IP2
IP1
FBT
IY
IP
C2
C1
IY
DD
CS
CS
IY2
IY1
VB
C3
IM
VB
VB
LM
IM
DM
IDC
VB
LM
IM
CSM
CSM
Fig. 13-11
Fig. 13-13
Voltage & current waveform in H period.
Iy
0
IY
VA
0
IM
0
VA
0
0
IDC
VB
C1
C2
IM
0
IDC
VB
0
0
0
C1: IY1+IP1
C2: IY2+IP2
Fig. 13-14
C3
0
C3: IP2-Iy1-IM.
Fig. 13-12
13-6
SECTION XIV
CLOSED CAPTION/EDS CIRCUIT
14-1
1. OUTLINE
The CC (Closed Caption) and EDS (Extended Data
Services) circuits extract data from from the incoming
video signal and decode them to generate displayable text
information. Major features of the CC/EDS circuit found in
the TG1-C chassis are as follows:
(1) All decoding performed in 1 chip
(2) Capable of processing field 2 data ( CAPTION 3, 4
TEXT 1, 2 EDS) as well as field 1 data ( CAPTION 1,
2 TEXT 1, 2)
(3) Display of text mode extended from 8 rows to 15 rows.
(4) 64 extended characters to handle Spanish and the like.
(5) Background attribute capability (8 colors + transparent)
2. DATA TRANSMISSION FORMAT
The CC/EDS data is transmitted having been superimposed
on line 21, field 1 (21H) and field 2 (284H). Waveform of
line 21
is shown in Fig. 14-1. Line 21 signal is composed of data of
7 cycle clock-run-in, start bit and 16 bit (8bits x 2 bytes).
10_50±0.5m s
4.15±0.1m s
33.764m s
12_910m s
0.12m s
b1
10.076m s
b3
b2
1
b5
b4
P
P
b7 A b1
b3
b5
b7 A
b6
b2
b4
b6
R
R
I
I
T
T
Y
Y
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Fig. 14-1 Line 21 waveform
14-2
20m s
3. DISPLAY FORMAT
The character display area of caption mode and text mode
consists of 32 characters x 15 rows as shown in Fig. 14-2.
On the front and back of each row, 1 character blank area is
respectively added. In caption mode, up to 15 rows can be
displayed at the same time. Characters viewed while in text
mode are displayed in a black rectangular box of 34
characters x 15 rows. EDS display format is shown in Fig.
14-3. CC or EDS can be displayed only when data of that
type has been transmitted.
SCREEN
LINE 43
ROW1
ROW15
LINE 237
1 CHARACTER BLANK AREA
32 CHARACTERS
1 CHARACTER BLANK AREA
Fig. 14-2 Caption / Text display area
(Green)
(White, Slant, Unerline)
(Cyan)
Network Name
Call Letters
(Green)
Time In Show
(Cyan)
Program Name
Prog. Length
Prog. Type
(Cyan)
(Yellow)
Program Description (4rows)
(Character background:black)
Fig. 14-3 EDS display format
14-3
4. CIRCUIT OPERATION
A block diagram of the CC / EDS circuit is shown in Fig. 144, and block diagram of QM01 is shown in Fig. 14-5.
The video signal which is input to pin 9 of UM01 is changed
to 1 Vp-p signal which is band-limited to 600kHz by the
input circuit, and it is supplied to pin 7 of QM01.
Inside QA01, line 21 signal information is extracted from
the input video signal, and is recovered on clock and data.
Recovered data is decoded by the command processor and
converted to a display signal of R, G, B, Ys in Output Logic
section.
The display signal is output at pins 18, 2, 3 and 17 in the
CMOS level of positive polarity. The display output and
OSD are switched by QR01 in UM01, and the selected
signal is sent to the V/C/D IC.
When CC/EDS and OSD are displayed concurrently, OSD
has the highest priority.
H. sync signal with negative CMOS level is input to pin 5
of QM01. This signal becomes the standard signal of a PLL
circuit in the IC. The loop filter for the PLL circuit is
connected to pin 9. QM01 is controlled by the I2C bus
connected to pins 14 and 15.
14-4
UM01 EDS/CC/RGB SW.
QM01 CC/EDS DECODER
XC144144P
UV01 A/V MODULE
Q501 V/C/D
Video
in
14-5
Fig. 14-4 CC /EDS circuit block diagram
V-AV EH
LPF
ATT
9
7
VIDEO
HIN
5
HD
INVERTER
11
30 HD OUT
12
31 VP OUT
6
36
OSD YS
1
37
OSD R
5
38
OSD G
2
39
OSD B
VD
VIN 13
QA01 uCOM
QR01 RGB SWITCH
Q89- I2C BUFFER
SCL1 37
2
SCL1
SCL2
6
SDA1 38
3
SDA1
SDA2
5
SCK
SDA
BOX 17
2 1A
13
15 SCK
R 18
5 2A
14
14 SDA
G
2
3 3A
B
3
14 4A
1 A/B
1Y
4
2Y
7
3Y
9
4Y 12
OSD-YS
R 22
G 23
B 24
OSD-R
OSD-G
OSD-B
18
3 1B
19
6 2B
20
10 3B
21
13 4B
Ys OUT
R OUT
G OUT
B OUT
+5V
12
IC XC144144P
VDD
Sllced Data
Data MOD
&
XFR BUF
Data Recovery
Data Sllcer
DLCK
COMP Video
7
Clamp
V
Sllce Level
Display
RAM
SYNC Sllcer
CSYNC
Timing Logic
COMP SYNC
Command Processor
and
CHAR
ROM
Decoder Control
Vertical CTR
And Control
13
VIN
Horizontal
Counter
R
Output
Logic
Phase/
Freq
DET
Loop
FIL
PFD
HIN
Loop
Filter
5
9
LPF
G
B
SDO
SDA
SCK
SEN
DOT CLK
SMS
14-6
Fig. 14-5 XC144144P QM01 block diagram
8
Data CLK
Recovery
VCO
Vss
AVSS
1
11
6
4 15 14 16
I2C
+5V
NC
Box
18
2
3
17
SECTION XV
DIGITAL CONVERGENCE CIRCUIT
15-1
1. OUTLINE
2-2 Circuit Operation
(1) When power is applied to the set, C711 resets the unit.
Vertical (VD) and horizontal (HD) sync signals are
applied to Q701 and Q707. These signals lock the PLL
(Q707) to 32 MHz, which is counter down in Q701 to
provided the clock.
(2) Q701 down loads the data in Q713 to RAM.
(3) Q701 processes the data, and sends it in serial form to
the D/A converters (Q703, Q704, & Q705).
(4) Onced processed, the comvergence wave forms are
amplified by Q715, Q717, and Q719.
(5) Next, the waveforms are filtered before they are output
from the digital convergence board.
The Digital Convergence circuit developes the correction
signals to eliminate geometric distortions in the red, green,
and blue CRTs. This new digital design is smaller than
previous convergence circuits, more accurate, and adjusted
via the remote control. Once adjusted, the data is saved in
an E2PROM and retrieved every time the set is powered up.
Memory capacity for one full screen of data is 4k.
2. CIRCUIT DESCRIPTION
2-1 Configuration
Figure 15-1 shows the circuit block diagram for the digital
convergence board. The digital convergence circuit consists
of the convergence processor (Q701), the PLL circuit
(Q707), the E2PROM memory (Q713), D/A converters
(Q703, Q704, & Q705), and pre amplifiers (Q715, Q717, &
Q719).
Convergence waveforms from the D/A converters are
amplified and shaped by Q715, Q717 and Q719, filtered,
and output from unit. The PLL clock is adjusted by L719,
to a basic frequency of 32MHz with no sync signal. Q701
generates a customer convergence test pattern and a service
convergence test pattern, and outputs them as R, G, B and
YS signals.
15-2
R
TEST PATTERN
Q713
B
Ys
E2PROM
MEMORY
Load
Q701 T7K64
Q703
Q704
C711
RESET
RH
FILTER
RV
FILTER
GH
FILTER
GV
FILTER
BH
FILTER
BV
Q717
D/A
Fig. 15-1
DATA
Q719
Q705
1/2048
CLK
15-3
FILTER
D/A
RAM (8x8x13bit)x3
Save
Q715
COUNTER
D/A
Q707
Q767
VD
PLL
HD
QA01
32MHz±0.005MHz
µ-CON
MAIN
BUS LINE
L719
Sub
BUS LINE
DIGITAL CONV. BOARD
BLOCK DIAGRAM
G
3. PICTURE ADJUSTMENT
This mode is designed so that ordinary user cannot use this,
and special operation is required to use this.
Data change is done by direct shift (cursor display) of
adjusting points ; 60Hz mode (NTSC) 8x8 /1 color.
The adjustment is done on 60Hz mode (NTSC).
3-1 Change of Memory (E2PROM)
Memory of Q713 E2PROM is nonvolatile, and adjusted data
is stored. Since data in RAM of Q701 is eliminated with
power OFF, the RAM is set by soft command of
microcomputer QA01 at every power ON. The adjusted
data which is obtained from screen-watching is once stored
in RAM inside QA01. The whole data in RAM which is
corrected on each adjusting point and is changed, is saved
into E2PROM (Q713) as a fixed data. The data capacity per
one screen requires 4k for 60Hz mode (NTSC).
3-2-2 To enter and to exit
Press MUTE key on remote hand unit twice and keep
pressing the key, press MENU key of set console.
Then service data will be displayed on top left of screen.
Under the condition, Press “7” key on remote hand unit, and
the screen shows crosshatch picture (Later, the first picture).
Press again “7” key, and the screen changes to crosshatch +
data display (Later, second picture). This time changed
data are automatically saved.
Further, press “7” key on remote, the screen returns to
original picture.
3-2 Service Mode
3-2-1 Outline
Service mode is controlled by software of microcomputer
QA01, and is one of function of set.
X + X + MENU
Service data display
(original picture)
The first picture
Remote
"7" key
The second picture
Remote "7" key
+automatic save
Fig. 15-2
15-4
Remote
"7" key
3-2-3. Picture
60Hz mode (NTSC) ..................... Correcting point Horizontal 8 x Vertical 8 (Arrow marks denote correcting point)
The first picture
The second picure
Data display
Cusor (red)
(Blinking)
Screen center
Fig. 15-3
The first picture
Crosshatch pattern. Pattern colors are three color display.
Cursor is blinking in red. When changed, condition is last
memory state.
Cursor is ........... Data change mode in lighting,
Cursor shifting mode in blinking.
Display color shows the color that data change is possible.
The second picture
When entering from the first picture to the second picture,
correcting wave of convergence is muted for one second.
During this period, the changed data is transferred from
RAM Q701 to E2PROM Q713, and saved.
The second picture is indicated with data on top left of the
first picture, therefore, convergence cannot be adjusted by
this picture.
(CAUTION)
Receive suitable signal for adjustment. Decide the center
by cross pattern of static convergence in menu, and adjust
convergence from center to circumference.
15-5
4. ADJUSTING PICTURE DIMENSION
(Green picture)
12xA
14xB
B
2
B
2
60Hz mode (NTSC)
2mm
48 inches 4:3 Screen size: Horizontal 975mm Vertical 732mm
Dimension A: 80.9mm Dimension B: 48.8mm
Fig. 15-4
15-6
5. KEY FUNCTION OF REMOTE
CONTROL UNIT
EDS
TV
E
CABL
VCR
TIMER
POWER
TV/VIDEO RECALL MUTE
MOVES CURSOR/LINE
UP
CURSOR
LOCK/UNLOCK
MOVES CURSOR/LINE
LEFT
ENTER CONVERGENCE
MODE & SAVE
1
2
3
4
5
6
CH
7
8
100
0
MOVES CURSOR/LINE
RIGHT
9
ENT
MOVES CURSOR/LINE
DOWN
RED CRT
ON/OFF
TOGGLES CURSOR
BETWEEN COLORS
VOL
RNT
BLUE CRT
ON/OFF
GREEN CRT
ON/OFF
Fig. 15-5
15-7
6. CONVERGENCE OUTPUT CIRCUIT
6-1 Outline
This circuit current-amplifies digital convergence correction
signal at output circuit, and drives by convergence yoke to
perform picture adjustment.
Digital convergence output signal 6ch adjustment is done.
(H-R/G/B) (V-R/G/B)
6-2-4. CONV-OUT mute
In power-on operation, transistors Q765 and Q766 are made
turned ON, and -15V is applied to pin 3 of CONV- OUT IC.
These cause mute operation on CONV-OUT.
6-2-5. Operation of IC
1) Q764 (TC74HC4050AP)
Sync signal which is input from P711 1 VD, 2 HD, is,
through buffer, supplied to digital convergence P708.
6-2 Circuit Description
6-2-1. Signal flow
Signal which is corrected by digital convergence, is output
to P708 (V, H R/G/B);
is input to Q751 (V) R/G/B, and is output to P713, P714 and
P715;
is input to Q752 (H) R/G/B, and is output to P713, P714 and
P715.
2) 3-terminal source
Q754 (+5V) Q755(+9V) Q756(-9V)
Source for digital convergence
3) Q767 (TC4066BP)
P711 4 SDAM, 5 SCLM : microcomputer. Busline,
through Q767, is input to Digital Convergence P709, and is
controlled.
6-2-2. Over current protection circuit
All currents of Power supply, -15V, +15V and +30V are
detected to protect CONV-OUT IC from damage due to
output short of CONV-OUT.
Current value: Normal ± 15V approx. 700mA
+30V approx. 200mA
Detecting curren ±15V approx. 1.8A or more
+30V approx. 700mA or more protecting operation
4) To adjust from outside of digital convergence :
Put adjusting jig into 6P socket of P720. Iscs turns from H
to L, switch of Q767 is changed over. Then busline from
microcomputer is cut off.
P720 3 SCLU, 4 SDAU
Controlled by external adjusting jig.
6-2-3. Pump-up source
CONV-OUT IC Q752 (H)
Pin 10 (+15V/H,PV)
Pin 5 (+30V)
By HD input signal, pump-up is done only in horizontal
retracing time.
Pump-up
Pump-up source waveform
Horizontal correction wafeform
+30V
+30V
+15V
+15V
0V
0V
-15V
-15V
Horizontal correction waveform
Fig. 15-6
15-8
P708
SCLM
SDAM
I2CS
SCLV
SDAU
R
G
B
HD
VD
+9V
-9V
+5V
RH
GH
BH
RV
GV
BV
DIGITAL CONVER
P720
Q764
7 6 5 4 3 2 1
P711
6 5 4 3 2 1
TC4066BP
Q767
(HD)
TC74HC4050
-9V
Q756
+9V
Q755
+5V
Q754
(REGULATER)
CNT
GND
SDAU
SLLU
INCS
GND
15-9
DFAI
GND
SCLM
SDAM
I2CS
HD
VD
+30V
+
C7765
+
C7766
(HD)
C7771
PROTECT
5V-1
NC
+15V
MUTE
Q765
5
Q766
3
B-H
5
3
B-V
MUTE
Q769
Q770
Q771
1 2 3 4
8
9
G-V
12
4
8
9
G-H
12
CONV-OUT
(+1501
(H)
10 H.PU)
4
10
5V-1
CONV-OUT
+15V
(PUMP UP)
D7702
D7701 Q757
(PROTECTOR)
P712
-15V
11
11
17
R-H
17
Q752
STK392-110
R-V
Q751
STK392-110
18
18
0.39Ω
R7765
0.33Ω
R7750
0.82Ω
R7782
H
V
H
V
H
V
P715
GREEN
P714
BLUE
P713
RED
CONVER
YOKE
(-15V)
(+15V)
(+30V)
CONVERGENCE (BLOCK DIAGRAM)
7. CONVERGENCE TROUBLESHOOTING CHART
Relay turns on
once but immediately
turns off.
Reray OFF
Relay operation sound
at power on.
Reray ON
No Convergence
correction wave.
OK
Check screen modes
of picture.
Convergence PCB,
pull out of P712.
Protect 1
Reray ON
Reray ON
Check power
supply circuit.
Reray OFF
Reray OFF
Check Q751, Q752
and repair.
Reray OFF
Check P708 R/G/B
correction wave.
Proceed to "protection
circuit diagnosis procedures".
OK
Check voltage at
±15V+30V pump up.
NG
Check power supply
circuit.
OK
Convergence output signals correction wave
Check DEF PC13.
OK
+30V
Check voltage across
±9V+5V Q754, Q755, Q756.
0V
OK
-15V
Vertical
Q751
(R/G/B)
NG
Are output signals
applied to H, Vblk of P711.
Pump-up
Horizontal
Q752
(R/G/B)
Check signals of all IC
and associated cirduits.
15-10
NG
Check Q754, Q755,
Q756 and repair.
LAB 3
DIGITAL CONVERGENCE
GREEN GEOMETRY
1. Put the set in the service mode and bring up the convergence cross hatch.
2. Push the 100 button to turn off the red tube, and RTN to turn off the blue tube.
3. Place the convergence template on the screen and align the center cross hairs with the tabs in the
bezel.
4. Use low tack masking tape to attach the template to the bezel. Try to get the template flat against
the screen to reduce parallax errors.
5. Push the 3 button on the remote until the blinking cursor in the upper left corner of the screen
turns green.
6. Move the blinking cursor to the right with the 6 button, then down with the 8 button until it’s one
line to the right of center. The 4 button moves the cursor to the left, and the 2 button moves it up.
7. Push the 5 button to lock the cursor in place.
8. Use the 2, 6, 8, and 4 buttons to align the intersection of the cross hairs with those on the
template.
9. Push the 5 button to unlock the cursor.
10. Move the cursor to another location and repeat steps 7 and 8. Moving the cursor in a counter
clockwise spiral to the various locations works best. Normally, you need to repeat the procedure
a second time to make fine adjustments.
RED CONVERGENCE
1. Remove the template and press the 100 button to turn on the red tube.
2. Press the 3 button until the red cursor appears.
3. Align the red cross hatch pattern to the green cross hatch pattern the same way you aligned the
green with the cross hatch pattern on the template.
BLUE CONVERGENCE
1. Push the 100 button to turn off the red tube, and RTN to turn on the blue tube.
2. Push the 3 button until the blue cursor appears.
3. Align the blue cross hatch pattern to the green cross hatch pattern in the same manner.
4. Push the 100 button to turn on the red tube and check the convergence with all three tubes on.
The cross hatch pattern should be white with no red, green, or blue present. However, depending
on how much the blue tube is defocused, a slight blue halo may show.
15-11
5.Push the 7 button then the power button to save the settings and exit the service mode.
ELECTRICAL CENTERING
1. Disconnect all video cables in the video 1 input.
2. Put the set in the service mode.
3. Push the TV/VIDEO button on the remote until the white cross hair pattern on a black
background is displayed.
4. Check the centering of the cross hair pattern with the centering tabs in the bezel.
5. If the horizontal position is off, push the channel up button until the HPOS register appears. Use
the volume button to center the pattern.
6. If the vertical position is off, push the channel up button until the VPOS register appears. Use
the volume button to center the pattern.
7. Push the TV/VIDEO button until the TV picture is displayed, then turn the power off.
8. Turn the set on and check the picture quality with a live video signal.
END OF LAB 3
15-12
SECTION XVI
OPTICAL SECTION
16-1
1. NECK COMPONENTS
NOTES:
1-1. Outline of Components Around Neck of The
Projection Tube
Fig. 16-1 shows names and mounting locations of neck
components around the projection tube.
Projection tube
Deflection yoke
Velocity modulation coil
Fig. 16-1
1-2. Theory of Operation
The neck components consist of, a deflection yoke assembly
(which consists of a main yoke, a sub-yoke, and a
.
centering magnet), and a velocity modulation coil
The main yoke of the deflection yoke assembly consists of
a horizontal and vertical deflection coil, and deflects electron
beams in horizontal and vertical directions.
The sub-yoke is called a convergence yoke and also consists
of a horizontal and vertical coils. The sub-yoke performs
distortion correction and color registration according to
correction currents supplied from the convergence output
circuits.
Moreover, a centering magnet consisting of two 2-pole
magnets is provided at end of the deflection yoke to adjust
the raster position.
16-2
1-3. Projection Tube
TP4688J, TP4880A
• Fluorescent screen: flat
TP48E60/61 TW56D90
• Fluorescent screen: inverted R 350mm
Fig 16-2
Electrons around the peripheral of the CRT screen come
into collision with the A/B lenses and are not used, thus
lowering contrast, etc.
Light beams around the peripheral of the CRT screen are
focused towards the center, thus increasing the amount of
light emitted towards the screens.
• Electromagnetic Focus
Electromagnetic focusing with magnets mounted around
the CRT neck.
• Electrostatic Focus
High unipotential focus
Eb
G5
G2 Screen
G4
G3
K
Focus
Fig 16-3
Since the deflection is carried out by using a magnetic field
applied from the outside of the neck, high deflection power
is obtained and focusing quality is high. Moreover, since
the coils are mounted on the outside of the neck, the
configuration of the deflection fields created inside the neck
has less distortion, thus the best beam pattern will be
obtained.
The best beam pattern is obtained at screen center and
screen edges by applying parabolic voltages for H and V
periods to the focus terminals.
This also assures a flat focusing characteristic across the
entire screen.
To obtain clearer pictures, a velocity modulation circuit is
also provided.
16-3
2. FUNCTION OF KEY COMPONENTS
2-1. Outline
The optical system of the TP48C60/61 consists of a screen,
mirror and lens assembly. A description will be given for
each block.
2-2. Theory of Operation
Screen
Mirror
FRESNEL LENTICULAR
Sheet
Sheet
Projection tube
Screen
Lens
Lens
Projection tube
Lens
Projection
tube
Optical coupling
system
Fig. 16-4
Refracting light beams running to screen
peripheral area to the G-axis direction
(screen center direction) with effect of
convex lenses.
Widening directional
characteristic in horizontal
direction.
Fig. 16-5
16-4
2-3-1. Effect of Fresnel Sheet
The shape of the lens has been changed to reduce focal
length.
(This allows the product size to be reduced, specifically in
the distance from front to rear.)
2-3-2.
Appearance of LENTICULAR Sheet
FRESNEL
sheet
Effect of
FRENSNEL sheet
Lens
Without FRESNEL sheet
Fig. 16-6
LENTICULAR lens
Black stripe
n
ree
Sc
n
tio
ec
r
i
ed
sid
Viewer side
Fig. 16-7
16-5
LENTICULAR sheet
2-3-3. Effect by LENTICULAR Sheet
If the light enters the front lenticular screen on the diagonal,
the light will be diffused in the same way as parallel light
incidence when viewed from the front of the TV.
TP4688J
TP4880A
(Body diffusion)
Projection
tube side
TP48C50/51
TW56D90
(Surface layer diffusion)
Viewer side
F2
F1
Diffuser
Incident
light
Outgoing
light
When light beams enter LENTICULAR
sheet in parallel.
F2
F1
Fig. 16-8
Outgoing
light
Incident
light
Light beams will be effectively used by collecting the
diffuser at surface of the layer, thus increasing the brightness
by about 10%.
Black stripe
When light beams enter LENTICULAR
sheet diagonally.
SCREEN GAIN
TP48C60/61
5.6
TW56D90
6.2
LENTICULAR lens
Fig. 16-9
16-6
2-4. Optical Coupling Effect
An liquid with a refraction index near that of glass is filled
between the projection tube and lens to suppress:
2-4-1. Optical Coupling Effect
(1) Light beams
,
emitted from the fluorescent
surface A advance up to the lens, but light beam
returns to the fluorescent surface due to the total
reflection.
(1) total reflection from the tube, thereby improving the
contrast
(2) This extremely lowers the contrast at the fluorescent
surface.
(2) interfacial reflection to reduce loss of light. Moreover,
with the cooling effect of the liquid, the power output of the
projection tube can be safely increased.
Assuming that the reflection index of air is 1.0 and that of
glass 1.5, the angle which causes the total reflection is 41.8°
That is, the light beams with an angle of q higher than 41.8°
can not exit from the projection tube. The light beams
returned to the fluorescent surface reaches 56% of the total
beams coming out from A.
Projection tube
Lens
Projection tube
fluorescene plane
Liquid (ethylene glycol + glycerine)
Index of refraction 1.4~1.45
Fig. 16-10
Lens
1
2
Air
q
Projection tube
face glass
3
Fluorenscene plane
A
Projection tube
Fig. 16-11
16-7
2-5. Lens
The lens system consists of a main lens (3 pieces of lens),
C lens, and the face plate of inverted gCRT (used as a lens),
and realizes a short focus optical lens system with less
quantity of lens.
With the short focus optical system employed, the depth of
the unit is reduced by about 30%, thus making the unit slim
and compact.
2-5-1. Optical Coupling Effect
Note: When making adjustments on the neck components,
it is always best to use dedicated drivers made of non
magnetic material to avoid any distortion while
making adjuctments.
Optical focus will be made according to the procedures
shown below. After completion of the electrical and optical
focus adjustments, convergence adjustments should be
made.
Liquid coolant
Plastic lens
Negative radius phospher
Loosen screws and adj ust the lens focus at
the best position by moving lenses left and right.
7" High bright
electrostatic focus CRT
Fig. 16-13 Lens focus adjustment
Glass lens
Black coating
Fig. 16-12
TP48C60/61
TW56D90
Projection
tube
LENSES
USPL DELTA 77
USPL DELTA 79
Deflection yoke
(Mounted projection tube)
Velocity modulation coil
V.M.Coil
Fig. 16-14 Mounting position of
deflection yoke and V.M coil
16-8
2-6. Focus Adjustment
(1) Turn on the static convergence switch and receives a
cross character signal.
(2) For easy adjustment, project one color to be adjusted
at a time on the screen. (Other colors can be interrupted
by putting caps on the lens.)
(3) Turn the electrical focus volume for the color to be
adjusted clockwise or counterclockwise so that the
focus at center of the cross character shows the best.
(4) Loosen screws securing the lens and move the lens
toward left and right until the best focus is obtained at
center of the cross character.
(5) repeat steps 3 and 4 to obtain the best focus. Finally,
secure the screws.
(6) Perform the convergence adjustment according to the
convergence adjustment method.
Focus pack
SCREEN
R
G
B
FOCUS
Electrical focus and gun drive
controls.
Remove 4 screws and
take off the cover which is in front
of the focus block.
Fig. 16-15
16-9
NOTES
16-10
Chapter XVII
Power Supply
17-1
Notes:
17-2
1. Power Supply Overview
A block diagram of the power circuit is shown in fig. 17-1. The power circuit consists of the following:
1) Standby Supply, which supplies the +5V-1 Standby to the microcomputer and +12V Standby to the On/Off Relay
(SR81).
2) Main Supply which supplies HORIZONTAL OUTPUT B+ (+125V) and AUDIO OUTPUT Vcc (+38V). The signal
process circuits are supplied by +5V-3, +5V-2, and +9V-2 via regulators from the 12V source of the Main Supply.
3) Sub Supply which supplies +30V, +15V and -15V for the convergence output board.
T840
POWER
TRANS.
TPW
1549AZ
+12V
REG.
+5V-1 (MICROCOMPUTER)
D801
Q801
VOLTAGE CONTROL
STR-Z3201
Q843
SW
T862
+12V
CONVERTER
TRANS.
R861
Q830
SW
Standby Supply
Q830
REG.
Q831
REG.
Q832
REG.
D840
F860
SR81
Q840
+38V
+5V-2 (for TUNER, COMB, V/C/D etc.)
+5V-3 (for PIP, ESD/C.C/RGB. SW)
AUDIO OUT Vcc
+9V
TPW
3332AS
Defl. Vcc (to V/C/D IC)
F470
R470
R479
1
3
B+ (+125V)
F.B.T. V.M
R471
+32V (TUNER)
R101
2
Z801
PROTECTOR
H1C1019
R883
Q862
PHOTO COUPLER
Main Supply
+9V-2 (for COMB, DSP, CRT-D etc.)
Q430
13
X-RAY
C471
+
F.B.T.(HEATER)
D471 R472
200V L.V.P. 35V O.C.P
14
16
D802~D805
F850
Q802
VOLTAGE CONTROL
STR57041
T888
CONVERTER
TRANS.
F801 T801 T802
TPW
3330AM
R7782
+30V
+30V
F851
O.C.P
Q768
+15V
-15V
LOW VOLTAGE PROTECTOR
Q853 Q854
Sub Supply
+15V
O.C.P
Q759
O.C.P
Q762
Figure 17-1 Power Supply Block Diagram
17-3
R7750
R7765
-15V
CONVERGENCE
CIRCUIT
2. Rectifying circuit and standby power supply
The rectifying circuit generates dc voltage sources from
the 117 Vac input. D899 is a metal oxide varistor used to
absorb surges due to line spikes, lightning, etc. The arrow
in fig. 17-2 indicates the path in which the surge is bypassed. C801, T801 and T802 are filters for abnormal radiation or line noise. For direct view sets the degaussing
circuit, using a thermistor, is supplied after SR81 (not
shown). R810 is used to suppress surge current during
switch-on. D801, along with C810, output a rectified and
smoothed DC voltage. T840 is the standby power trans-
F801 D899
former. D840 along with C840 output a rectified and
smoothed 12V signal for driving relay SR81 and for supplying the +5V regulator, Q840. Q840 supplies the standby
+5V-1 and the reset signals for the microcomputer as well
as other circuits. When the power is switched on, QA01
(ICA01), the Main Microcomputer, sends a high signal from
pin 7 to the base of QB30, turning it on. This causes the
base of Q843 to go high and thereby turn it on. When Q843
turns on, current flows through the coil of SR81, activating the relay and thereby switching the main power on.
160 Vdc
Rectified
Output
+
C801
D801
117Vac
C810
R810
_
Surge
T801
+5V-1
Q843
QB30
.12Vdc
All voltages shown are
during ON condition.
4.2Vdc
SR81
10.9Vdc
Q840
1
3.9Vdc
2
T840
MICOM
POWER
On=5V
Off=0V
3
5
+5V (to MICOM)
4
Reset 5Vdc
0V
C842
D840 C840 C843
Figure 17-2 Standby Supply
3. Main Supply Circuit
The circuit in fig. 17-3 is a current resonant switching type
power supply that incorporates a hybrid IC, Q801 (STRZ3201). The current resonant power circuit is highly efficient in that it operates with very low power consumption
and very little noise. In the case of a short on the load side
of T862, the AUDIO OUTPUT, Low B, and B+ circuits are
protected with F899, F890 and F470 respectively. F860 is
used to protect the primary side of T862.
4. Outline of Current Resonant Type Supply
Fig. 17-3 shows the configuration for the Current Resonant type power supply. A start-up voltage is sent to Pin 10
to begin operation. VIN source voltage of 160V is applied
to Pin 1. Pin 14 is tied to ground for the negative phase of
the MOS-FET configuration. The Primary winding of T862
and C870 are connected in series to form an LC Series
Resonant Circuit. The converter transformer, which is
driven by a push-pull MOSFET configuration located inside Q801, operates in forward mode.
The automatic voltage control operation is performed by
the detection of the B+ voltage (125V) fed into the error
amp, Pin 5, of IC Z801, then output through Pin 3 to the
photo coupler. Next this signal is fed into the primary Oscillating (OSC) circuit, located inside IC Q801 (Pin 6) which
controls the frequency of the ON/OFF time, via an internal
logic IC, for the MOS FET configuration.
17-4
R861
D862
C876
IC Q801 STR-Z3201
D876
17.4Vdc
89Vdc
10
78Vdc
16
VB
Vcc
D864
L863
R862
F860
R871
78Vdc
3
2
G(H)
HO
VIN
TSD
1
START
OVP
150-160Vdc
1.3Vdc CD
R1
DELAY
9
LATCH
Logic
REF
D801
F890
F899
F470
OUT
C869
15
+
+12Vdc
+38Vdc
B+ 125Vdc
72.6Vdc
R872
OC
12
C867
R870 R865
R2
OSC
CONTROL
OC
OSC
COM
.O1Vdc
C870
T862
14
Css
C866
CT
CONT
8
4.7Vdc
R863
6
4.7Vdc
5
ERROR
AMP
Z801
0V
R3
R4
C874
RT
7
GND
LO
0V
7Vdc
G (L)
11
4
3.5Vdc 5.3Vdc
13
PHOTO
COUPLER
Q862
7Vdc
L864
D879
R864 C862 R867
Figure 17-3 Current Resonant Supply (Main)
5. Fundamental Theory of LC Series Resonant Circuit
The LC series resonant switch mode power supply is a frequency regulated power supply operating above resonance
(see figures 17-3 and 17-4). The LC series resonant circuit
is composed of the primary winding of T862 and C870. A
negative feedback circuit is used to control the output of
the transformer. The feedback circuit, which monitors the
125Vdc source, is composed of the error amp inside Z801
and the photo coupler (Q862). This feedback is applied to
the CONT input (Pin 6) of IC801 to control the frequency
of the internal oscillator (OSC). When the load increases
on the secondary side of the transformer, the frequency
decreases (operates closer to resonance) and the current
increases. Conversely, when the load decreases, the frequency increases and the current decreases. Table 17-1
shows the voltages developed on T862 secondaries.
VL (v)
increased
load
decreased
load
Nominal
Operating
frequency
T862 Pin #
Voltage
Pin 2*
47 Vp-p
Pin 3
Ground
Hot
Side*
Pins 4, 5*
148
Vp-p
Pins 6, 7*
127
Vp-p
Pin 9
27 Vp-p
Pin 10
27 Vp-p
Pin 11, 12,
15
e
Resonant point
1
f=
2π LC
Table 17-1 T862 Voltage Chart
Frequency
Ground,
Signal Side
Pin 13
256
Vp-p
Pin 14
256
Vp-p
Pin 16
81 Vp-p
Pin 17
81 Vp-p
* Reference Hot Side Ground (T862, Pin 3) when
measuring Pins 2, 4, 5, 6, and 7. CAUTION, USE
ISOLATION TRANSFORMER.
Fig. 17-4 Resonance Curve
17-5
6. Main Supply Actual operation
Refer to Figure 17-5 diagram and waveforms.
1. Start-up
5. Css terminal (Pin 8) - soft start
When power is applied to the set, a start-up voltage of
16V is applied to pin 10 of IC Q801. At the same time,
charging of C869 (pin 9) induces a delay to the internal
latch circuit to prevent the Over Voltage Protect (OVP)
circuit from shutting the set down.
When power is first applied, the switching frequency is
set high by capacitor C866 and resistor R863, resulting
in soft start of the switching supply. Thus, current (surge)
in the POWER MOSFET output is limited to provide
stable starting of the supply sources. After initial startup, the circuit operates at its nominal frequency (70-80
kHz).
2. Output switching element
Two power MOSFETs operating in push-pull mode are
used for switching. The on-off timing of each is controlled by the logic inside Q801. To avoid a short circuit
from occuring a delay is used between the turn off of one
MOSFET to the turn on of the next.
6. CD terminal (Pin 9) - Latch Delay
The Latch circuit shuts the power supply off (shut-down)
when a fault is detected. Shut-down occurs by detecting
errors from the following:
3. CT terminal (Pin 5) - basic oscillation
• Over voltage protection (OVP) circuit
The frequency of the internal oscillator is controlled by
the Oscillator Control block. The frequency is determined by the charge and discharge of capacitor C862
connected to CT terminal. The oscillator generates a ramp
waveform at Pin 5. The ramp waveform charges up to 4
V (typical) and discharges to about 2.5 V. The charging
time is the output-on period, and discharging time is the
off period (see OSC OUT SIGNAL waveform of Figure
17-5). The lowest oscillation frequency is determined by
capacitor C862 and resistor R867.
• Thermal shock detection (TSD) circuit
• Over current protection (OCP) circuit
• Loss of and no recovery of Main B+
The charging time of capacitor C869 connected to the
CD terminal (Pin 9) is used to delay the operation of the
Latch circuit when power is initially applied. If the unit
goes into shut-down, temporarily remove ac power to
reset the latch circuit.
7. OC terminal (Pin 12) - Over Current Detect
4. CONT (Pin 6) - frequency control
Current flowing out of the CONT terminal (Pin 6) varies
the charging current of oscillator capacitor C862, which
in turn controls the frequency of the Output (Pin 15) signal. The control current is determined by the
Photocoupler. The Photocoupler phototransister side current is determined by the feedback current of the photodiode side. The photodiode current is determined by the
Error Amp inside of Z801, which is monitoring the
+125V source. Thus, the terminal current (CONT) corresponds to the feedback from the +125V output.
This is to detect over-current in the LC series resonant
circuit.
8. Over voltage protection (OVP) circuit
If the Vcc terminal (Pin 10) exceeds 22V (typical), the
Latch circuit is engaged (shutdown) .
9. Thermal shock detection (TSD) circuit
17-6
This is to make the Latch circuit operate when the IC's
internal temperature exceeds 150°C.
R861
D862
C876
IC Q801 STR-Z3201
D876
17.4Vdc
89Vdc
10
78Vdc
16
F860
R871
78Vdc
3
VB
Vcc
D864
L863
R862
2
G(H)
HO
VIN
TSD
OVP
START
DELAY
LATCH
REF
1
150-160Vdc
1.3Vdc CD
R1
9
Logic
D801
F890
F899
F470
OUT
C869
15
+
72.6Vdc
R872
OC
12
C867
R870 R865
OSC
CONTROL
OC
OSC
COM
.O1Vdc
C874
Css
R863
D879
6
4.7Vdc
0V
R3
CT
CONT
8
C866
C870
14
R4
4.7Vdc
+12Vdc
+38Vdc
B+ 125Vdc
R2
5
RT
GND
LO
G (L)
11
4
7
3.5Vdc 5.3Vdc
0V
T862
ERROR
AMP
Z801
13
7Vdc
7Vdc
L864
R864 C862 R867
PHOTO
COUPLER
Q862
DELAY TIME
=4V
(PIN 5)
CT PIN VOLTAGE
=2.5V
OSC OUT SIGNAL
(Internal)
(PIN11)
LOW SIDE
GATE VOLTAGE
(PIN2)
HIGH SIDE
GATE VOLTAGE
ON
OFF
OFF
ON
(PIN 15)
PUSH-PULL
OUT VOLTAGE
=VIN
PIN VOLTAGE
(PIN 1)
OV
(PIN 15)
PUSH-PULL
OUT CURRENT
OA
Figure 17-5 Current Resonant Supply with Wavefoms
17-7
7. Scan-Derived Voltages (FBT)
Figure 17-6 shows the voltages derived from the FBT of
the Horizontal Deflection circuit. The FBT derives 200V
for the Video Output circuit from pin 3, +35V for the Fail
Safe, H.V. Regulator, Blanking, Dynamic Pin Cushion
(DPC), and Vertical Deflection (V.D.) circuits from pin 6,
and -27V for the side DPC circuit from pin 5, Heater voltage from pin 9, Automatic Frequency Control (AFC) and
blanking signal from pin 10, and the Automatic Black Level
+9V-1
(ABL) signal from pin 8. A 12Vdc source is also derived,
via pin 7 and D408, to supply the SVM and DPC circuit
boards. In addition, the 12Vdc source is used to develop
the +9V-1 source via a 9 Volt regulator made up of Q420,
Q421, and D427. High voltage is supplied from the secondary along with Focus and Screen voltage sources developed from a tap on the high voltage secondary of T461.
AFC
BLANKING
10
HEATER
9
+9V-1 Reg.
(Q420, 421,
D427)
FBT
29-30kV
to 2nd ANODE
4
D408
R448
+12V
7
C447
C307
R327
+35V
6
Z410
D307
C310
FOCUS X 3
D460
-27V
FOCUS
X3
5
C460
R469
SCREEN
X3
B+
125Vdc
R444
G2
X3
2
C448
D406
200V
R443
DF In
(Dynamic Focus)
3
C446
Q404
Collector
8
1
T461
Figure 17-6 Scan Derived Sources
17-8
ABL
8. Protector Module (Z801)
Figure 17-7 shows the standardized protector module
(Z801). The following are the four different sections within
the Protector Module: Error Amp, Switch/Latch, B+ OCP,
and X-Ray Protect. In addition the Over Current Protect
(OCP), Over Voltage Protect (OVP), and Under Voltage
Protect (UVP) circuits are routed through the internal
Switch/Latch circuit to trigger the unit off through the Protect output (Pin 16).
The Error Amp circuit monitors the B+, 125V line, via
Pin 1. The Error Amp controls the current through the
photodiode of photocoupler Q862. When the B+ voltage
decreases Q862 conducts less and when it increases, Q862
conducts more.
The Switch/Latch circuit is used to turn off SR81 relay in
case of over current, over voltage or under voltage. In shutdown mode, Pin 16 (Protect) latches low, which turns QB30
off. When QB30 turns off Q843 turns off. This causes the
relay (SR81) to open and thereby disconnect the power.
To SR81
Relay
QB30
RB30
Active High
5V
From ICA01
R470
.56
Power (Pin)
0.1V
4.9V
1
Q843
4.4V
0V
R471
R884
3
R890
2
6.2V
5
IZ
3
In the X-Ray Protect circuit, Pin 11 provides a reference
voltage of +25V. If the High Voltage increases abnormally,
Pin 9 of T461 senses the increase and increases the voltage
through R472. This increased voltage is applied to D471,
which rectifies AC to DC. The increase in Vdc is applied
to Pin 13, which will trigger the internal latch circuit and
output a Low on Pin 16. As long as +5v-1 is applied to
pin15, the remote control hand unit will not recover the
power. The AC power line must be disconnected to reset
the latch.
+5V-1
(125V)
B+
4
Q862
In the B+ Over Current Protect (OCP) circuit, the current is being compared across R470, which is applied
through Pins 1 and 2. The resistance of R470 is so small
that changes in voltage equate to larger changes in current.
When a large enough change in voltage occurs the internal
latch circuit outputs a low on Pin 16, which shuts the unit
down.
(125V)
B+
R479
C472
16
15
Protect
C-Out
C474
5V-1
4.9V
116V
* See Protect Circuits
starting on page 17-9.
+35V Over Current Protect
+30V Over Current Protect
+15V Over Current Protect
-15V Over Current Protect
+30V Over Voltage Protect
+15V Over Voltage Protect
+15V Under Voltage Protect
-15V Under Voltage Protect
200V Under Voltage Protect
2
OCP
1
14
B+
0V 0.1V
Gate
12
22V
+25V
13
X-Ray
11
C471
D471
R472
9
X-RAY
Protect
T461
Control
Switch
/ Latch
Error
Amp
B+ OCP
X-Ray
Protect
4 , 8 , 9 , 10
PIN: VACANT PIN
14 GATE terminal
Z801 (HIC1019)
7
GND1
17
GND2
Figure 17-7 Protector Module Circuit
17-9
When the voltage at this
terminal becomes approx.
1.5V or more, protection
circuit operates.
9. Sub Supply
The Sub Supply is located on the Convergence Out/Power2
board. Figure 17-8 shows that the Sub Supply is a ringing
choke converter, using hybrid IC STR57041. Operation
begins with a start-up voltage that is applied through R852.
This provides a trickle base current to Q1 (internal to the
IC, Pin 2 of Q802), which causes it to turn on. When Q1
turns on, the collector current begins to flow. During this
start-up time the current is flowing through the primary
winding of T888 through Pins 2 and 5. At the same time
current will flow through Pins 7 and 8, which create the
detection winding, as well as Pins 8 and 9, which create
the base drive winding. During the first half cycle of the
AC pulse no current flows through the detection winding
because of the reversed polarity of D856. Pin 9, however,
provides positive feedback for the base, as the electromagnetic inductance increases, to rapidly turn Q1 on. As Q1
becomes saturated the current through the primary winding decreases.
This decrease in current through the primary winding, reduces the electromagnetic inductance across the base drive
winding, which decreases the voltage to the base of Q1 and
thereby rapidly turns Q1 off.
T888 uses a detection type winding through Pins 7 and 8.
The secondary windings are proportional to the detection
winding. Subsequently, any fluctuation in voltage across
the secondary windings is sensed across the detection winding which is fed back through Vo sense (Pin 1). This feedback is used to regulate the On/Off time of the internal
switching transistor Q1.
R846, C845, R852 and D848 create a voltage clamping
circuit that allow the collector voltage of Q1 to stay within
a specified level. R847, C855, R848 and D849 filter the
base voltage. Q850, Q851, Q852, C856, D855, R857 and
R859 create the Slow-start circuit. C856 determines the
rate of the start-up time.
D857 L853
Bridge rectifier
output
C856
+
3
C857
2
D858 L855
Vo Control
Vout Sense (-)
5
1
R847 D849
0.0V
+15V
10
9
2
4
C880
8
+
C881
C882
C847
C846
+
11
C853 R850
-35V
D856
7
12
+
-42V
C848
R859
R860
Q802
STR57041
+
C859
15
D848
R858 C855
C849
D850
Earth (E)
C858
R857
C850
0.2V C851
Base Drive (B)
C845
L858
R852
163.7V
+30V
R846
D855
Input (C)
F851
17
5
−15V
13
R853
R854
Q851
T888
Q852
Figure 17-8 Sub Supply
17-10
D859 L857
10. Protect Circuits
D370
Protect (active high)
To Pin 14 of Z801
R372
35V
Q370
LOAD
3.9K
35.3V
5.6K
C370
R371
1.5
+35V
R370
+35V OVER CURRENT PROTECT CIRCUIT
(Located on Deflection/Power board)
Figure 17-9 +35V Over Current Protect Circuit
(Located on Deflection/Power Board)
+30V
LOAD
R7782
0.82
R7783
330
R7784
470
C7770
29V
Protect (active high)
To Pin 14 of Z801
Q768
29V
0V
R7763
2.2K
Q758
Q757
Figure 17-10 +30V Over Current Protect Circuit
(Located on Convergence Out/Power2 Board)
17-11
+15V
LOAD
R7750
0.33
R7749
330
R7751
470
C7760
16.1V
Protect (active high)
To Pin 14 of Z801
Q759
15.8V
0V
Q758
R7747
2.2K
Q757
Figure 17-11 +15V Over Current Protect Circuit
(Located on Convergence Out/Power2 Board)
-15V
LOAD
R7765
0.39
R7764
330
R7763
470
C7763
-16.2V
Protect (active high)
To Pin 14 of Z801
Q762
-16V
1.5V
R7758
2.2K
Q761
Q757
Figure 17-11 -15V Over Current Protect Circuit
(Located on Convergence Out/Power2 Board)
17-12
(36V)
+30V
R848
D865
D863
(24V)
Protect (active high)
To Pin 14 of Z801
+15V
R849
D861
D860
Figure 17-12 +30V/+15V Over Voltage Protect Circuit
(Located on Convergence Out/Power2 Board)
(5.1V)
+12V
D854
+15V
R877
R873
D866
0V
0.7V
Q853
R879
D867
0V
R874
R880
R875
-15V
-14.9V
Protect (active high)
To Pin 14 of Z801
Q854
-14.3V
-15V
R876
Figure 17-13 +15V/-15V Under Voltage Protect Circuit
(Located on Convergence Out/Power2 Board)
17-13
9.4V
+9V-1V
R389
R390
0V
6.2V
6.8V
Q340
D315
6.2V
R347
6.1V
Q341
D341
Q352
0V
CRT PROTECT
R346
0V
200V
R392
C340
Protect (active high)
To Pin 14 of Z801
Figure 17-14 200V Under Voltage Protect Circuit
(Located on Convergence Out/Power2 Board)
D471
R472
Q757From X-RAY
Pin 9 of T461
To X-RAY
Pin 13 (Z801)
(23V)
C471
Figure 17-15 X-Ray Protect Circuit
(Located on Deflection/Power Board)
17-14
LAB 4
POWER SUPPLY SHUTDOWN CIRCUITS
SECTION 1
VOLTAGES UNDER NORMAL CONDITIONS
Place the unit in the service position by removing the chassis light box and place it on its side in an
upright position with the power cord up. (See FIG. 17-16) Connect a signal to the ANT1 input. You
may want to refer to the actual schematic diagram for a clearer understanding of the circuitry.
PROTECT CIRCUIT MEASUREMENTS:
1. Connect the (-) lead of the peak/hold meter to pin 17 of Z801 (See FIG. 17-16, #1) and record
the DC voltages on the following pins:
PIN 11)__________
PIN 13)__________
PIN 14)__________
PIN 15)__________
PIN 16)__________
RELAY CONTROL CIRCUIT MEASUREMENTS:
2. Locate Q843. (See FIG. 17-16, #2) Record the voltages on the following:
C__________
B__________
E__________
3. What does Q843 control, and how does it control it?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
OVER CURRENT, OVER VOLTAGE, AND UNDER VOLTAGE PROTECT CIRCUIT
MEASUREMENTS:
4. Connect the (-) lead of the p/h meter to the (-) side of C882 (See FIG.17-16, #3).
5. Measure the voltage on the anode side of D865. (See FIG.17-16, #4)
Anode D865__________
17-15
6. Measure the voltage on the anode side of D860. (See FIG. 17-16, #5)
Anode D860__________
7. Measure the voltage on the collector of Q853. (See FIG. 17-16, #6)
Collector Q853__________
8. Measure the voltage on the anode side of D867. (See FIG. 17-16, #7)
Anode D867__________
9. Measure the voltage on the collector of Q757. (See FIG. 17-16, #8)
Collector Q757__________
10. Connect the (-) lead of the p/h meter to the (-) side of C310 (see FIG. 17-16, #9).
11. Measure the voltage on the collector of Q370. (See FIG. 17-16, #10)
Collector Q370__________
SECTION 2
VOLTAGES UNDER SHUTDOWN CONDITION
1. Locate the (X) pin (P415) and the (R) pin (P416) (See FIG. 17-16, #11)
2. While monitoring pins 13 and 16 of Z801 on the p/h meter, jumper pins (X) and (R) together.
3. After the shutdown, record the voltages on pins 13 and 16 of Z801. (See FIG. 17-16, #1)
PIN 13)__________
PIN 16)__________
The above exercise allows you to see what happens when the X-Ray protect circuit shuts down
the set.
4. How is this determined?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
NOTE: SHUTDOWN OCCURS WHEN THE VOLTAGE INCREASES TO
APPROXIMATELY 25V.
17-16
5. While shorting the base of Q853 (See FIG. 17-16, #6) to ground, monitor and record the
collector voltage using the p/h meter.
Collector Q853__________
6. What have you simulated by shorting the base to ground?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
7. Why does a change occur on the collector and where is this change sensed?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
8. Look on the schematic diagram labeled “Convergence Out/Power2”, in the upper right side.
Find D865 (zener diode) on the +30V supply line. How would you determine what the peak
voltage would be before the over voltage protect circuit would operate?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
9. Look on the schematic diagram labeled “Convergence Out/Power2”, in the upper right side.
Find D860 (zener diode) on the +15v supply line. How would you determine what the peak
voltage would be before the over voltage protect circuit would operate?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
10. Remember when you measured the anode sides of D865 and D860 earlier? Well, if the set, your
working on, is in shutdown mode, how would you determine if it was caused by over voltage on
the +30v or +15v lines?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
17-17
11. While shorting the base of Q757 (See FIG. 17-16, #8) to ground, monitor and record the
collector voltage using the p/h meter.
Collector Q757__________
12. What have you simulated by shorting the base to ground?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
13. Measure the voltage drop across R7750 (See FIG. 17-16, #12), R7782 (See FIG. 17-16, #13)
and R7765 (See FIG. 17-16, #14).
R7750__________
R7782__________
R7765__________
14. List a procedure of how would you determine which one of the over current protect circuits
were causing the shutdown?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
17-18
R7765
#14
R7782
#13
R7750
#12
Q757
#8
Q843
#2
D865 #4
Q853
#6
C882
#3
D867
#7
D860
#5
C310
#9
1
X
Z801
#1
Q370
#10
17
Figure 17-16
17-19
R
#11
NOTES
17-20
SECTION XVIII
DYNAMIC FOCUS CIRCUIT
18-1
1. OUTLINE
2. H DYNAMIC FOCUS CIRCUIT
In TP48C51, a static focus system is employed in the projection
tube.
Degradation of the focus quality at peripheral screen is
improved by applying focus correction voltages (parabola
voltages in H/V periods).
The dynamic focus circuit creates this focus correction
voltage and consists of an H and a V dynamic focus circuit.
2-1. Theory of Operation
Fig. 18-1 shows a block diagram of the circuit which develops
an H parabora correction voltage.
To obtain a flat focus characteristics at center and peripheral
of the screen, the focus correction is carried out by applying
the H sync parabola correction voltage (efH=700 Vp-p) and
the V sync parabola correction voltage (eifv=300 Vp-p) to
the focus electrode in addition to the focus DC voltage of Ef
(=EHx0.27~0.29).
ef H
+
ef V
H pulse
(AFC)
Integrated
circuit
CO
Step-up
transformer
Copuling
capasitor
Focus
electrode
EF
ef H
V dynamic
focus circuit
EF
Fig. 18-1 Block diagram of H dynamic focus circuit
18-2
ef V
0
1V
!
V2
V1
1H
F.P
L450
10
9
L401
2
T461
9
C1
Focus Pack
2
3
5
1:n
12
T400
C477
From v dynamic focus circuit
1
Fig. 18-2
18-3
S
To
BLUE DRIVE
EF
From FBT
F
S
F
S
F
To
RED DRIVE
2-2. Circuit Operation
The H pulse developed at pin 10 of the pulse transformer
T461 enters the integration circuit consisting of L450 and C1.
The C1 does not exist in the actual circuit as shown in a dotted
line. The C1 is an equivalent capacitance of the stray
capacitance of Cs in secondary side of the step-up transformer
T405 converted into the primary side and can be expressed
as:
To
GREEN DRIVE
C1=n2Cs
The H pulse is integrated with L450 and C1, and a sawtooth
wave current of IC1 flows into C1.
Accordingly, a parabora voltage V1 integrated is developed
across C1 and this is used as the input voltage (primary side
voltage) for the step-up transformer. A parabora voltage V2
stepped-up and inverted is obtained at secondary side (F, P
terminals) of T400. This parabola voltage is mixed with the
V parabola voltage described under the V dynamic focus
circuit, and the mixed voltage is superimposed with the focus
DC voltage (about 9kV) through a coupling capacitor Co,
and supplied to the focus electrodes of three R, G, B tubes.
3. V DYNAMIC FOCUS CIRCUIT
3-1. Theory of Operation
Fig. 18-3 shows the circuit which develops the V parabola
correction voltage.
Flyback pulse
Integrated
circuit
Amplifier
circuit
Deflection
output
Rectification
block
efH+efV
H dynamic
focus circuit
Sawtooth wave
CO
Coupling
capacitor
Focus
electrode
EF
ef H
ef
EF
0
Fig. 18-3 Block diagram of V dyanamic focus circuit
18-4
V
3-2. Circuit Operation
A sawtooth wave voltage developed across (R305) in the V
output circuit is cut in its DC component and the AC
components of the voltage is integrated into a parabola form
by a mirror integrator in the first stage and amplified with a
specified gain level set by R362/R361. The amplified parabola
wave enters an op. amplifier in the next stage and again
amplified. The op. amplifier works as an inverting amplifier
and the gain is determined by (R368/R369)/R366. The
parabola voltage amplified in this way enters base of Q361,
amplified in an inverted form, and developed as the V focus
parabola voltage (300 Vp-p, DC component 60V). This
voltage is mixed with the H focus parabola voltage in passing
through R483, resulting in mixed parabora voltage consisting
of a H component of 700 Vp-p and a V component of 300 Vpp. Thus obtained mixed output is fed to the focus electrodes
of R, G, B projection tubes through the coupling capacitor
stated under 2-2.
The parabola level of the V focus parabola output voltage can
be adjusted by varying R369 and the DC voltage level by
varying R354.
The power for Q361 is obtained by rectifying collector pulse
of the deflection output circuit with the rectification circuit
Z470. The rectification circuit Z470 is assembled as a separate
block in considering safety because of its high rectified
output voltage of about 1000V.
18-5
H. deflection output circuit
Q360
V Coil
Q404
Focus power supply lock
C306
1
VCC
GND
VCC
3
2
4
5
6
7
8
Z470
9
D305
H. dynamic focus circuit
R368
C362
C361
R362 C363
R357
R367
12
18-6
Fig. 18-4 V output circuit
R361
Q301
T400
2
R480
R369
R363
D364
R365
R366
R356
+12V
C300
9
5
L401
R360
D360
C364
R354
F.P
!
EF
F
To
RED DRIVE
S
F To
GREEN DRIVE
S
F
S
To
BLUE DRIVE
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