ANNEX 2 TO - Diagramasde.com - Diagramas electronicos y

Mechanical and electrical parts list
CTN-BB CHASSIS
ANNEX 2 TO
SERVICE MANUAL
CTN-BB
Philips CPT 20”/21” can be replace by Samsung CPT 20”/21” or vice versa, modifying components (supplied together
with CPT a Kit) according the following table.
This supplement refers to change of Microprocessor for Circuit Reference 7600.
Chassis type is changed from CTN to CTN-BB.
3130 105 2423.1
18
Contents
Page
Introduction
2
Circuit Diagrams
3-6
Print board layout
7-8
Mechanical Parts List
CTN-BB CHASSIS
Circuit Description
Small signal processing
9 - 10
RBG Amplifiers
11
Sound Circuit
11
Power Supply
12 - 13
Deflection
14
Microcontroller/Text
14 - 15
Service components
16 - 17 - 18
Introduction
The main change on this Chassis to the previous CTN-AA type are the introduction of
new Microprocessors for both - Text and Non Text Models.
Also the Flyback Transformer for 20″ ONLY MODELS has been changed.
The relevant Circuit Diagrams and PCB Layouts have been amended to show these
changes, plus minor corrections/updates have been made to all other circuit information
where this has been found necessary.
Page 16, 17 and 18 shows different Part Numbers for the Component changes on the
new chassis.
POSITION
*
SCREEN
*
TV MODEL
*
COLOUR
Please use the original CTN Service Manual for all other parts information.
HOW TO ORDER
EXAMPLE: FRONT CABINET OF TV700TX COLOUR BLUE: A * 14 * TV700TX * AZ
2
17
NG-BLACK
BL-WHITE
GR-GREY
MA-IVORY
GO-DARK GREY
VE-GREEN
RS-PINK
RJ-RED
AZ-BLUE
PL-SILVER
PRINT BOARD LAYOUT
CIRCUIT DESCRIPTION
1.- SMALL SIGNAL PROCESSING (Diagram A)
The small signal is processed by TDA8361, (TDA8360 no scart) for Pal sets and TDA8362 for Pal/Secam
sets (IC 7015), including IF detection, video processing, chroma decoder, RGB processing, sync processor
and FM sound decoder.
1.1- IF detection (IC7015/6A)
- IF input (pins 45,46): The IF signal comes from pin 11 of the tuner to the IF SAW (Surface Acoustic Wave)
filter (1015) and the IF-detector IC7015/6A (pins 45 and 46).
- IF filter (1015): The IF bandpass characteristic, determined by the SAW filter, is 33.4 to 38.9 MHz. for BG
sets, 33.5 to 39.5 MHz. for PAL I sets and 32.4 to 38.9 MHz. for DK sets.
- IF oscillator (pins 2,3): Carrier frequency, present in coil L5040, is tuned at 38.9 MHz. for BG sets or
39.5 MHz for Pal I sets
- AGC voltage (pin 47): The AGC delayed voltage is applied to pin 1 of the tuner. It should be adjusted
for 1mV. antenna signal by means of R3021 (pin 49).
- AFC signal (pin 44): The Automatic Frequency Control is obtained from the reference signal of the IFdetector. C2037 smoothes the AFC voltage.
- Identification (pin 4): The identification output is applied to pin 16 of the µC. This signal is high in case of
signal detected.
- Video output (pin 7) : This baseband CVBS signal with 2Vpp of nominal amplitude, also contains the FM
intercarrier sound signal. Sound is filtered out by a ceramic trap (1032 or 1033) which frequency can be
different depending on the system: 5.5 MHz. for BGLL’, 6.0 MHz. Pal I or 6,5 MHz. for DK.
Multistandard sets
-The IC TDA8362 changes automatically between negative (BGIDK) and positive (LL’) modulation.
The IC also determines if the AGC circuit should control at the top white level of the video (positive
modulation) or at the top sync level (negative modulation).
-Saw filter (1015) bandpass characteristic is modified by BG/L switching signal proceeding from the
microcontroller:
- For BGIDK reception BG/L is low, D6014 does no conduct and the bandpass filter is tuned by
5012 and 2013 at 32.9MHz. to 38,9 MHz.
- For LL’ reception BG/L is high, D6014 conducts and so the bandpass filter is tuned by 5012 and
C2014 at 32.4 to 38.9 MHz.
-Oscillator frequency is controlled by the L/L’ switching signal:
-For BGIL reception L/L’ is low, D6042 conduct and so coil 5043 is connected in parallel to 5040.
- The circuit is tuned to 38.9 MHz.
- For L’ reception L/L’ is high, D6042 does nor conduct and the circuit is tuned to 33.4 MHz. by L5040 only.
1.2- Source select, luminance and chroma separation (IC7015/6B)
- Source select (pin 13, 15, 16): The internal CVBS signal is now fed to pin 13 IC7015/6B. External CVBS
from the pin 20 of Euroconnector is present on pin 15. The source selector switch between internal (pin 16 = 0V.)
or external (pin 16 = 8V.).
- Luminance and chrominance separation: Chrominance signal is filtered out (-20dB) by a luminance
notch filter which is internally calibrated at the subcarrier frequency (4.43MHz).
- Secam reference (pin 32): Pal or Secam signals are recognized using a DC level by bi-directional
communication line between this pin and pin 1 of IC7250.
-If IC7015/6C has detected a Pal signal, Vpin 32 is made 1,5V. By then the demodulated R-Y and BY outputs (pins 30, 31) are applied to delay line IC7271.
-If IC7015/6C has not detected a Pal signal, Vpin 32 is made 5V. By then the demodulated R-Y and
B-Y at outputs (pins 30, 31) are not used.
-If IC7250 has detected a Secam signal, Vpin 1 IC7250 becomes low, sinking typical 150µA. current
from pin 32 (5V.) of IC7015/6C, which one detect this current to know that a Secam signal has been
detected. In this case R-Y and B-Y signals are applied to the delay line IC7271 via outputs of
IC7250 (pins 9 and 10).
This bi-directional communication line uses AC level to calibrate the 4,43MHz. between the PLL and chroma
cloche filter of IC7250.
1.4- RGB-dematrixing(IC7015/6D)
- R-Y, B-Y inputs (pins 28, 29): The R-Y and B-Y signals come from delay line (IC7271) and the Y signal
comes (internally) from IC7015/6B.
The sandcastle pulse coming (internally) from the IC7015/6E (pin 38) synchronizes RGB dematrixing and
suppresses the RGB signals during line and frame flyback.
- Video controls (pins 17, 25, 26): These inputs for contrast, brightness and saturation can be adjusted
from 0,5V to 4,5V by the µC. If beam current is limited reducing contrast with D6289 circuit.
- RGB inputs (pins 22, 23, 24): External RGB inputs come from Euroconnector and are switched by fast
blanking.
- Fast blanking (pin 21): When voltage of pin 21 is 0,4V. internal RGB is used. For a pin 21 voltage between
0,4V. and 3,5V. the set switch to external RGB.
If voltage of pin 21 is 4V. both internal and external are deleted. The up uses this status to insert RGB signals
from OSD generator directly to RGB outputs.
Fast blanking can switch signals for full screen (by a DC voltage) or for a part of the screen (by a pulse
voltage).
- RGB outputs (pins 18, 19, 20): See RGB amplifier.
1.5- Horizontal synchro (IC7015/6E)
- Start up (pin 36): When the set is switched on, voltage at pin 36 rises and when exceeds 7V. the horizontal
oscillator starts running at approx. 25 KHz. (slow start). After the line starts, main supply of IC7015 (pin 10)
comes up to 8V. and the line frequency changes to 15625 Hz.
- Standby (pin 36): This pin is used also for standby function. In this case the voltage is reduced to 3V. by
the uP and so the line is shut down.
- Hor. oscillator: This oscillator is fully integrated and internally calibrated. Frequency is obtained derived of
chroma oscillator on pin 35 of IC7015/6C.
- Hor. sync separator: This circuit (fully integrated) separates hor. pulses of CVBS proceeding from 7051/6B.
- Oscillator synchro (pin 40): Oscillator is synchronized with video signal by a first control loop circuit. The
control voltage is present at pin 39.
- Hor. phase control (pin 39): Line fly-back (pin 38) is synchronized with oscillator by a second control loop
circuit. The control voltage is present at pin 39. Phase can be adjusted by 3354.
- Hor. output (pin 37): Oscillator is converted in square wave voltage at this pin.
- Sandcastle (pin 38): This pin is used as line fly-back input and also as sandcastle output. Levels of
sandcastle pulse are 5,3V for burst detection, 3V. for line blanking and 2V. for frame blanking.
1.6- Vertical synchro (IC7015/6E)
1.3- Chroma Decoding (IC7015/6C)
8
Pal or Secam signals are recognized automatically by the IC. For Pal signals decoding is made in IC7015/
6C and for Secam signals in IC7250 (TDA8395).
- Pal signal: This signal is amplified and demodulated. The 4.43 MHz. reference crystal for chrominance
demodulation is present at pin 35 of IC7015/6C. The R-Y and B-Y out-puts (pins 30, 31) are applied to
chroma delay line IC7221 (TDA4665).
- Secam signal (pin 27): This signal is applied to pin 16 of Secam decoder IC7250.
- Vertical oscillator (pin 42): Frequency is obtained dividing frequency of chroma oscillator on pin 35
IC7015/6C. At pin 42 a sawtooth signal is present. Resistor 3342 is used to correct vertical amplitude with
beam current.
- Vert. sync. separator: It separates frame sync. pulses from CVBS and so synchronizes frame oscillator.
- Vert. drive (pin 43): This out-put is used to drive the vertical amplifier (7400)
- Vert. feedback (pin 41): this feedback is proportional to deflection current and is used to correct the vert.
drive signal.
9
10
2.- RGB AMPLIFIERS (diagram B)
PRINT BOARD LAYOUT
- RGB inputs : The RGB signals available at pins 20, 19 and 18 of IC7015/6D are drived by emitter followers
(7210, 7211, 7212), to RGB amplifiers.
- Reference voltage (7225): An internal reference voltage of 2.5V. is produced on the emitter of transistor
7225 to keep the black level stable.
- RGB amplifiers (7205, 7218, 7227): Signal is inverted and drived to the CPT by RGB amplifiers. To
improve high frequency amplification there are small capacitors (2204, 2217 and 2230).
- Flash-over protections: Clamping diodes to +8V. (6203, 6216, 6229) and 1K5 series resistors (3203,
3216, 3229) are added for protect the circuit from CPT flash-over.
- White adjustment: The gain of B and G amplifiers can be adjusted by 3213 and 3214.
- Cut-off adjustment: The black level of the CPT can be adjusted by 3207, 3220, 3234 and Vg2.
3.- SOUND CIRCUIT (diagram C)
3.1- FM Sound detection (IC7015/6F)
- FM input (pin 5): FM sound is extracted from baseband video (CVBS) proceeding of IF detector and
filtered through 1136 (5.5 MHz. for BG sets, 6.0 Mhz. for Pal I sets, 6.5 Mhz. for DK sets).
- FM demodulation: FM - mono sound demodulation takes place in IC7015/6F. No adjustment is required
because demodulation is doing by an automatic PLL (4.2 to 6.8 MHz.).
- De-emphasis (pin 1): Sound frequency characteristic is defined by de-emphasis capacitor C2112 at pin 1.
- External FM audio out (pin 1): The signal at this pin is amplified by T7114 and T7115 to drive the
euroconnector sound outputs (pins 1,3).
- External FM audio in (pin 6): External audio proceeding of euroconnector (pins 2,6) is applied to this pin.
Selection between internal or external is done by pin 16 of IC7015/6B.
This output is drived to pin 3 of the final sound amplifier IC7187 (TDA7052 or TDA7056).
Multistandard sets:
-FM demodulation: This function is done in the same way that no multi sets. The only difference consist
of a second Pal I 6MHz. filter (1135) in addition to the 5,5MHz. BG filter (1136). 6MHz. filter is switched
off for BG reception by transistor 7170 depending on BG/I signal.
-AM demodulation: In Multistandard sets, also AM demodulation for LL’ systems is necessary. AM
sound is extracted directly from the tuner instead of from baseband video.
AM Sound detection (IC7125)
- AM input (pins 1,16): AM signal at 32,4MHz. for L system or 39,9MHz. for L’, is removed from IF
signal coming from tuner by SAW filter 1137 (double band pass characteristic). Sound is switched by
T7126, D6115, TS7127 and D6116 depending on L/L’ signal: For L’ reception (L/L’ is high) IF signal is
present at pin 1, and For L reception, IF signal is present at pin 2.
The required frequency spectrum is fed to pins 1 and 16 of the AM demodulation IC7125.
- AGC (pin 3,5): C2126 and 2127 are AGC related storage capacitors.
- AM Sound output (pin 6): The demodulated signal at pin 6 of IC7125 is supplied to the source selection
switch (pins 1, 5 IC 7140).
AM Sound switching (IC7140)
- External audio out (pin 15): Audio out is selected between AM sound (pin1) or FM sound (pin2) by
internal switch depending on BG/L signal (pin 10).
- Audio in (pins 3, 4, 5): Top switch in IC7140 select between internal AM sound (pin 5) and EXT sound
from SCART (pin3) by INT/EXT signal (pin 9). The output of this selector (pin 4) is fed to input pin 6 of
FM demodulator (IC7015/6F).
- Internal AM audio switching (pin 13): This pin is switched to 8V when the set is in L or L’ system (AM
sound). Then, pin 1 of IC7015/6F is 8V. and this IC switches internally its sound input from pin 5 to pin
6, where AM sound is present. (Sound proceeding from pin 4 of IC7140 can be internal AM or external).
11
7
4.3- Protections
- Overload protection (pin 2): This is produced if T-on is increased till Vpin 2 voltage reaches the foldback
point (see signals 4.5). The IC will switch into overload mode (off and on continuously).
- Output voltage protections (pin 6): Limiting values of Vpin 6 voltage (7.25 and 16V.) provide under and
overvoltage protections for the circuit.
- Mains overvoltage (pin 3): The voltage at pin 3 IC7515 is a measure for the mains voltage and so the DC
voltage across C2505. As soon as the voltage Vpin 3 reaches 6.6V. the supply will stop running.
4.4- Secondary side
- Line supply: The value to adjust the supply is 101,5V. for 14" CPT’S, 102,5V. for 17" CPT’S and 107V. for
20"/21" CPT’S. This supply is also used to obtain the +33V. varicap voltage by D6602.
- Auxiliary supply (+11V.): This supply is used for sound output amplifier, for start up the line circuitry and
for the stand by of the microprocessor. +5STB is regulated by T7525 and D6575. A +5V. power on reset
signal (POR) is obtained during start up by R3573 till T7571 conducts by D6570.
4.5- Power supply signals
V cont
V pin 5 = V GS (7525)
I DS (7525)
V DS (7525)
13
5
22
B3
3509
B5
47
J2
3510
D5
47
J4
3512
D4
49
C3
3513
D4
1500
A2
3516
E3
2401
I1
3517
D5
2402
J2
3518
D5
2404
K2
3519
B4
2405
L2
3520
B4
2414
H2
3521
E5
2415
I2
3523
D4
2416
J2
3524
B4
2440
H5
3525
B4
2442
I5
3527
E5
2443
L5
3528
E4
2444
H5
3540
F5
2445
J5
3570
F4
2446
K5
3571
F4
2448
J3
3573
G4
2449
J3
3574
F4
2450
I4
3576
F5
2451
I4
3577
F5
2453
L6
5441
I5
2458
J3
5443
K5
2460
L4
5445
K3
2463
L5
5447
J3
2470
I3
5449
K5
2500
B3
5480
I4
2502
D3
5500
C3
2504
D3
5525
E3
2505
D4
5532
F5
2506
B6
5534
F3
2508
E5
5540
F5
2509
B4
5541
F6
2510
D5
5550
D6
2511
D5
5552
E4
2514
D6
6416
I2
2515
D5
6417
H2
2516
D3
6440
H6
2520
D5
6443
L5
2523
B5
6447
J5
2524
E4
6449
L6
2530
F3
6451
I4
2532
F5
6470
J3
2534
F2
6502
D3
2540
F6
6503
D3
2561
G4
6504
D3
2562
G4
6505
D3
3235
J5
6515
D5
3238
J5
6516
E3
3400
K1
6521
D6
3401
K2
6530
F3
3402
J1
6540
F5
3403
K2
6570
F4
3404
L2
6571
F4
3405
L2
7400
H2
3406
L2
7440
H5
3407
L2
7445
J5
3408
H2
7514
C4
3410
L2
7525
E4
3411
L2
7571
F5
3412
K2
7575
F4
3415
J2
9400
J2
3416
J2
9460
L4
3440
H5
9480
I4
3441
H6
9506
E6
3442
I6
9523
D4
3444
H5
9524
C5
3445
I5
9560
G5
3448
K5
9561
G6
3449
K5
1M1
A3
3451
I4
1M2
C2
3455
H4
1M5
J4
3456
H4
1M6
I3
3457
J3
2M1
A2
3460
L4
2M2
C2
3470
J3
2M6
J5
3480
I4
3M6
J5
3501
C3
4M5
J4
3504
A3
4M6
L4
3507
B5
5M5
K2
3508
D5
6M5
J2
3.2- Sound amplifier (IC7187)
B3
1679
C12
24B-24C B5
25B-26 B4
25C-26 B5
2602
G2
2610
G2
2611
H2
2622
G7
2623
H6
2624
H6
2629
H6
2630
H5
2635
C11
2636
C11
2641
F12
2648
C10
2651
F2
2656
H9
2659
G12
2660
C3
2669
B10
2677
E2
2680
C11
2681
C12
2685
C3
2691
D2
2692
G9
3600
C5
3601
H2
3602
H2
3603
G2
3604
G2
3605
G2
3606
F2
3607
F2
3608
F8
3609
G4
3610
G2
3611
H2
3612
H2
3613
H6
3614
F5
3615
H5
3616
F5
3617
H5
3618
G4
3619
F5
3620
F5
3621
F7
3622
F7
3623
G6
3624
G6
3625
F6
3626
G6
3627
G6
3628
F6
3629
G5
3630
F3
3631
F3
3632
G5
3633
H6
3636
B10
3637
B11
3638
H11
3639
F11
3640
G10
3641
G11
3642
G11
3643
F11
3644
G12
3645
F11
3646
D1
3647
G10
3648
C10
3649
F12
3650
C6
3651
F4
3652
F10
3653
F10
3654
G9
3655
G9
3656
H9
6
3657
3658
3659
3660
3661
3662
3663
3664
3665
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3680
3681
3682
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
6602
6616
6641
6642
6644
6663
6691
7600
7601
7605
7638
7640
7641
7642
7644
7651
7665
7670
7672
7673
7685
7686
7691
9052
9148
9266
9609
9610
9611
9614
9616
9618
9650
9651
9652
9653
9658
9663
9665
9670
9671
9678
9679
9686
9692
C6
G12
G13
C3
C7
C4
C3
B9
B9
C9
B10
B10
C9
C6
B8
B7
B8
C3
C2
H7
C8
F7
G7
G7
H3
H3
H3
H3
C5
F1
F3
G3
C4
C6
C6
C4
G9
C5
G2
H5
H11
H11
H12
B3
E2
D2
F7
F2
G11
G11
G11
G11
G12
G10
C9
C10
B8
B7
H8
G3
E1
B8
B7
B11
H4
F1
A13
G5
F7
A14
H10
F4
G4
A13
G4
C3
B3
C10
C9
F1
C1
G3
F9
Sound amplifier can be TDA7052 for 14" and 17" models or TDA7056 for 20" and 21" models.
Amplified sound is drived to the headphones output and loudspeakers. If headphones are connected, loudspeakers
are switched off.
Volume control on DC level is present at pin 4 for TDA7052 or pin 5 for TDA7056.
4.- POWER SUPPLY (Diagram D)
Mains isolated switched mode power supply (SMPS), controlled by IC7514 (TDA4605) in variable frequency
mode.
- Switching behaviour: The switching period is divided in on-time, when energy is extracted from the
mains into the primary winding (8-12 of 5525), off-time, when energy in the transformer is supplied to the
loads via secondary windings of 5525 and dead when no energy is extracted or supplied.
- Standby mode: Output voltages are present when the set is on stand by, due to standby is done cutting
line deflection. On-time is lower and power consumption is very low.
4.1- Primary side
- Degaussing: R3501 is a dual PTC (2 PTC’s in one housing). After switch on set, PTC is cold so lowohmic and so degaussing current is very high. After degaussing, PTC is heated so high-ohmic, so in
normal operation degaussing current is very low.
- Rectifier: Mains voltage is filtered by L5500, full wave rectified by diodes D6502-D6503-D6504-D6505
and smoothed by C2505 (300V. DC for 220V AC mains).
4.2- Control circuit (IC7514)
- Start up and supply (pin 6): When the set is switched on, a current via R3507 is applied to pin 6. When
C2514 is charged to 15V. the power supply starts and a current from pin 5 to T7525 is drived. T7525 and
starts conduction and a voltage across transformer windings is built up. The voltage across winding 4-2 is
rectified by diode D6521 and used to supply the IC on pin 6.
- Soft start (pin 7): The capacitor C2523 causes a slow increase of the duration of the output pulse during
start up.
- IC output (pin 5): This output drives T7525. R3523 is a fuse resistor to protect IC from short circuits in
T7525. D6516 limits the maximum voltage in T7525.
- Start conduction of T7525 (pin 8): A voltage proceeding from winding 4-2 is applied to this pin. The zero
crossing detector recognizes the complete discharge of the energy stored in the transformer core, in addition
to a dead time depending on C2508. This circuit guarantee that T7525 starts conduction at minimum Vds
voltage (see signals 4.5 pag 13).
- Primary current info (pin 2): Current primary winding is simulated by a pin 2 voltage.
- Output voltage info (pin 1): The voltage across winding 4-2 is rectified by diode D6515, divided by
R3527, R3518 and R3508 and applied to pin 1. Internal control voltage (Vcont) inversely proportional to V
pin 1 is generated. Tipical Vpin1 is 400 mV.
- Output regulation (pins 1, 2, 8): IC7514 stabilizes output voltage by controlling T-on and so the frequency
and the duty cycle:
Start pulse to T7525 is determined by pin 8 circuit (see signals 4.5 page 13 ).
Then a sawtood voltage Vpin 2 is generated at pin 2. Stop pulse to T7525 is produced when Vpin 2
reaches Vcont.
Output control is done by the following way:
If output is higher, Vpin 1 is higher, Vcont is lower, T-on and output will be reduced.
If output is lower, output will be increased.
Output voltage of supply can be adjusted by R3518.
Mains voltage variation is stabilized in the following way:
If mains voltage is higher, slope in the sawtood voltage Vpin 2 is higher, stop point is reached before
and T-on is reduced.
If mains voltage is lower, T-on is increased.
12
5.- DEFLECTION (Diagram E)
4
42
L1
3216
D6
1135
L8
3217
D6
1136
L8
3218
C7
1137
J7
3219
D6
1990
D3
3220
D5
2101
I8
3221
D6
2109
J1
3222
E6
2112
K6
3224
E7
2117
K8
3225
E7
2124
I6
3226
F7
2125
I6
3227
E7
2126
J7
3228
E6
2127
J6
3229
E6
2128
J6
3230
F6
2143
L8
3232
D7
2152
M6
3233
F6
2155
M6
3234
F5
2156
H2
3236
E4
2169
L8
3237
E4
2170
M8
3244
F6
2180
M7
5101
I7
2184
L4
5235
E4
2185
L4
6115
I8
2187
K3
6116
J8
2188
K3
6170
L8
2189
M4
6205
B6
2191
L2
6218
D6
2192
L2
6227
E6
2202
B7
7015
L7
2204
C6
7114
J2
2206
F5
7115
J1
2217
D6
7125
I7
2230
F6
7126
J8
2237
F4
7127
J8
3111
J2
7140
J3
3112
J2
7170
M8
3114
J2
7187
L4
3115
J2
7205
B6
3117
J8
7210
B7
3118
I8
7211
D7
3119
I8
7212
E7
3120
J8
7218
D6
3121
J8
7225
F7
3124
H6
7227
E6
3125
J5
9110
J4
3126
J5
9111
J2
3143
L8
9112
J1
3144
L7
9114
K6
3151
L7
9125
J5
3152
M6
9143
L5
3155
H4
9156
I2
3156
I4
9157
I3
3170
M8
9183
L4
3171
M8
9190
L3
3173
L8
9191
L3
3184
L5
9191
M2
3185
L5
9192
J3
3189
K4
9201
E7
3191
K2
9202
C7
3194
L2
1L1
C8
3202
B6
1L2
F5
3203
B6
1M3
M2
3204
C6
2L1
D8
3205
B7
2L2
F4
3206
C6
2M3
L2
3207
C5
3L1
D8
3208
C6
3L2
F4
3210
C7
3M3
L2
3211
D7
4L1
B8
3212
E7
4L2
F4
3213
B7
5L1
B8
3214
D7
L3
F3
3215
D6
L4
C4
5.1- Frame deflection
This function is performed by the integrated circuit TDA3653 (7400).
- Frame supply (pins 6, 8, 9): Pin 9 is used to supply the IC except output stage which one is supplied by
pin 6. At pin 6 there is a higher voltage during flyback time. This is produced adding the flyback signal
present at pin 8 to a +25V. supply by D6416 and C2415. Pin 8 is also used to drive vertical flyback input at
pin 37 of the up. (IC 7600)
- Vertical input (pins 1, 3): The input circuit is driven by pin 44 of IC7015/6E. Vertical signal is amplified and
inverted.
- Vertical output (pin 5): Vertical output is applied to deflection coil. DC current is suppressed by C2404. A
voltage proportional to current deflection is present in R3411/12 and a feedback of it is sent to pin 42 of
IC7015/6 by 3407, so that amplitude can be adjusted by 3410. DC feedback is present in R3406. Linearity
is corrected by the network around C2405.
- TRC protection (pin 7): When frame deflection is broken down, the tube is protected blanking all the
picture by pin 7 output.
5.2- Line deflection
The final line transistor is driven by the transformer 5441, whose primary winding is driven by the transistor
T7440 connected to the line drive output of IC7015/6E.
The horizontal deflection stage is carried out in a conventional way, with the deflection transistor (T7445)
and line transformer (5545).
Beam current info (BCI) is present at C2460.
There are the following auxiliary supply voltages obtained from line transformer (5545):
+25V.: To supply frame deflection..
+12V.: To obtain +8V. by IC7016 (diagram A) for small signal, +5V. by T7001 (diagram A) for the tuner
and for the microcontroller.
6.- MICROCONTROLLER/TEXT (Diagram E)
The CTN-BB chassis is designed to accept 2 different microcontrollers: SAA5531 and SAA5541.
Both microcontrollers are mounted in the same position (7600), and the associated circuitry is the same.
The ROM of the ICs contain an specific program that assures all the functions of the appliance, including a
MENU to control the set is (see Instructions Manual).
For no TXT sets SAA5541 is used.
For TXT sets SAA5531 is used which one also contains a teletext decoder, including the following functions:
TXT on/off, reveal, freeze, temporary cancellation, clock, subcode, zoom, index, flof, page +/-, X/26 and 8/
30 packet decoding (station identification and start-up page).
Following there is an explanation of the different functions of the microcontroller indicating pins number
assigned:
- Power supply (pins 31, 39, 44): The IC has several +3,3V power supplies, analog (pin 31), core (pin 39),
and periphery ( pin 44 ). All supplies are present during stand by.
- P.O.R. (pin 43): POR (power on reset) is activated when the set is switched on (see 4.4 pag 13 ). If the
system shows abnormal behaviour it is important to reset it switching off/on the set. Reset can be produced
also connecting pin 43 to +5V. for an instant.
- LED (pin 20): The LED (6663) lights up with a low current when the television set is ON and with a high
current when the set is on Standby. While the set is receiving a remote control signal, the led is blinking.
- RC5 (pin 45): The commands transmitted by the remote control handset are received by infrared receiver
(1685) and passed to the microcontroller for decoding.
- Control keys (pins 10, 11, 12): When a control key is activated, the correspondent pin is connected to
ground.
14
- I2C bus (pins 49 and 50): The microcontroller is connected to non-volatile memory IC7685 (EEPROM)
via bus I2C. Personal preferences (PP) and channel data are stored in the memory. The system can store
79 channels (with the data on tuning voltage and band) and personal preference.
- Service (pin 7): If this pin is connected to earth when the set is switched on, the unit will go into Service
Default Mode (see Repair Facilities in chassis CTN Service Manual).
- Options (pins 14, 21, 52): While start up, the microcontroller checks option pin voltages to know the
special features of this chassis. This one is implemented changing the associated components of these
pins. Different options (menu, multistandard, etc. ) can be seen on tables of diagram E.
- Multistandard out-puts (pins 46, 47, 48): These signals are only used on multistandard units, for
switching the system for decoding sound and video. Signals from pins 46 and 47 are inverted and
set at the correct level by transistors 7672 and 7673, respectively. After they are inverted together
with the signal from pin 48, they make up the system status lines: BG/I is high for Pal I system, BG/
L is high for L and L’ systems and L/L’ is high for L’ system.
- OSD synchronization (pins 36, 37): In order to synchronize the OSD and the TXT information with the
picture signal, the VERT FLYBACK signal (pin 37) and HOR FLYBACK signal (pin 36) are added in inverted
form to the integrated circuit. Due to this if the video signal is lost, the TXT keeps synchronism. - Video
inputs (pins 23 and 24): These inputs are only used on TXT sets. The teletext information is extracted from
the video signal inserted on pins 23 (internal video) and 24 (external video), depending on status of INT/
EXT (pin 8).
- Oscillator (pins 41 and 42): A 12-MHz. oscillator is determined by a 12-MHz. crystal between pins 41 and
42.
- Tuning (pins 1, 9, 16, 51): The unit has a VST (Voltage Synthesized Tuning) system. This system works by
tuning to a station on the tuner through a linear variation of the tuning voltage (V-VARI) from 0V. to 33V.
applied on pin 2 of the tuner. It is generated on pin 1 of the uP and converted to an adequate level for the
tuner using T7605. The AFC signal (Automatic Frequency Control) of IF detector is added to the tuning
voltage V-VARI by R3689 and R3688 to compensate for the slow variation of the tuning feature.
While searching for the station, pin 51 is set on high, which means that the AFC voltage will not be added to
the V-VARI. If an IDENT signal is received on pin 16 while searching for a station, the uP stop searching and
checks via input pin 9 if the tuning is correct and whether the AFC signal can be activated again.
- AGC auto tuning (pin 30): This pin is used to limit the AGC voltage in automatic tuning so that noise
signals are not memorized.
- Band switching (pins 15, 17, 18): There are 3 outputs for band switching pin 15 for VHFI, pin 17 for VHFIII
and pin 18 for UHF. The uP controls the channel band in the tuner by a voltage of +5V. at the correspondent
output.
- Picture and sound adjustments (pins 2, 3, 4, 5, 6): Volume control (pin 2), brightness control (pin 3),
colour control (pin 4), contrast control (pin 5), and sharpness control (pin 6).
The RC networks are used to convert the modulated pulse output to a DC voltage level. These settings can
be pre-programmed in the memory as a personal preference (PP). Mute is controlled internally on the up
during automatic station search or when the signal received is interrupted (detected via the IDENT signal on
pin 16).
- INT/EXT (pin 8): When this output is 0V. the set is switched to external via transistor (7877). This signal is
added to the signal from pin 8 of Euroconnector, so that either of them can be used to switch to external. This
line is also used by the microcontroller as an input line, to switch the adequate video input (internal or
external) used for decoding TXT.
- Standby (pin 19): When this output is high, the set is switched to stand by. The start-up voltage of the
TDA8361A (pin 36) is reduced and the line oscillator stops.
- Fast blanking (pin 35): This pin is used for delete the video picture signal while RGB insertion is produced.
- NIL (Pin 27): This control signal is used (only on TXT sets), to eliminate interlacing for TXT signals. It is
applied to the vertical deflection by switching transistor 7640.
- RGB outputs( pins 32, 33, 34): The RGB outputs are used for On-Screen Display (OSD) and also for
TXT (TXT character set is used for both functions). RGB signals are applied trough common base amplifiers
(7641, 7642, 7644) to RGB outputs of 7015 (pins 20, 19, 18).
15
1001
1015
1032
1033
1272
2001
2002
2003
2005
2006
2007
2010
2011
2013
2014
2015
2016
2017
2018
2019
2022
2025
2030
2034
2037
2041
2043
2044
2045
2050
2053
2080
2082
2084
2261
2262
2265
2267
2268
2271
2272
2273
2274
2275
2279
2280
2284
2285
2286
2291
2292
2293
2297
2340
2350
2351
2354
2366
2370
2371
2850
2852
2856
2860
2876
3000
3001
3002
3003
3004
3005
3006
3007
3008
3010
3011
3012
3013
3017
3018
3019
3020
3021
3022
3023
3026
3029
3030
3031
3032
3033
3043
3044
3045
3049
3051
3260
3261
3262
3272
3273
3275
3280
3
F7
C4
E3
E4
I5
G6
H7
F6
G8
G8
F2
B4
B4
B4
A3
F5
F5
B5
C5
G1
D6
D5
E2
E4
E2
B2
B2
A2
D2
G3
E4
G5
G5
G5
J5
J5
I5
I3
I3
I1
J2
J2
K1
L1
L3
L3
M4
M4
M5
K6
K6
K6
H1
B9
A8
A7
A7
B9
C7
C7
I8
I8
I9
H7
M8
F8
E6
E7
E7
E8
F7
E9
F9
F9
B4
B3
B4
E6
C5
C5
B5
C4
E5
E5
E6
E8
E3
E2
E3
E3
F4
B2
A2
D2
B3
E5
I5
M3
J5
J1
J1
L1
H3
3284
3285
3286
3289
3290
3291
3292
3340
3341
3342
3345
3350
3351
3353
3354
3370
3371
3372
3841
3843
3845
3848
3850
3851
3852
3853
3854
3855
3858
3860
3862
3865
3871
3875
3876
3879
3880
3881
3882
3883
3884
5001
5010
5012
5015
5032
5040
5043
6001
6014
6020
6042
6275
6289
6372
6849
7001
7015
7016
7030
7250
7271
7875
7876
7877
9001
9002
9003
9004
9005
9012
9015
9016
9017
9020
9021
9034
9035
9043
9051
9080
9115
9124
9261
9262
9265
9271
9289
9331
9354
9366
9367
9370
9371
9372
9600
9810
9812
1M7
2M7
3M7
4M7
5M7
M4
M4
M5
M5
K5
K5
K5
B8
B8
B9
D7
C7
A7
B7
B7
D7
D8
D8
J7
J7
K7
L7
I8
I7
J8
J7
I8
K7
L7
I7
L7
L7
M8
L8
M8
J8
J9
J8
K8
K8
M7
F6
B5
B3
G2
E3
C2
B2
F6
A3
B5
B2
L1
L5
D8
L7
F6
D4
F1
E2
H2
K1
M8
J9
K8
G8
H7
F6
E6
F6
A4
G9
G2
D7
G3
G3
F2
M8
A2
E5
G6
A4
G2
M3
K6
G2
J3
M5
D7
M1
A8
C8
C7
C7
D8
F6
L8
K9
M5
M4
M4
M3
M3