LMD-1420/1410 Service Manual

LCD MONITOR
LMD-1420
LMD-1410
SERVICE MANUAL
1st Edition
! WARNING
This manual is intended for qualified service personnel only.
To reduce the risk of electric shock, fire or injury, do not perform any servicing other than that
contained in the operating instructions unless you are qualified to do so. Refer all servicing to
qualified service personnel.
! WARNUNG
Die Anleitung ist nur für qualifiziertes Fachpersonal bestimmt.
Alle Wartungsarbeiten dürfen nur von qualifiziertem Fachpersonal ausgeführt werden. Um die
Gefahr eines elektrischen Schlages, Feuergefahr und Verletzungen zu vermeiden, sind bei
Wartungsarbeiten strikt die Angaben in der Anleitung zu befolgen. Andere als die angegeben
Wartungsarbeiten dürfen nur von Personen ausgeführt werden, die eine spezielle Befähigung
dazu besitzen.
! AVERTISSEMENT
Ce manual est destiné uniquement aux personnes compétentes en charge de l’entretien. Afin
de réduire les risques de décharge électrique, d’incendie ou de blessure n’effectuer que les
réparations indiquées dans le mode d’emploi à moins d’être qualifié pour en effectuer d’autres.
Pour toute réparation faire appel à une personne compétente uniquement.
LMD-1420/1410
Table of Contents
1. Service Overview
1-1.
1-2.
1-3.
1-4.
1-5.
Appearance Figure ...................................................................................... 1-1
Board Location ............................................................................................ 1-1
Disassembly ................................................................................................ 1-2
1-3-1. Rear Cover ................................................................................. 1-2
1-3-2. Q Board ...................................................................................... 1-2
1-3-3. GA Board ................................................................................... 1-3
1-3-4. Inverter Board/BA Board ........................................................... 1-3
1-3-5. DC Fan/Speaker ......................................................................... 1-4
1-3-6. J Board ....................................................................................... 1-4
1-3-7. LCD Panel .................................................................................. 1-5
1-3-8. H Board/X Board (X Board: LMD-1420 only) .......................... 1-6
Unleaded Solder .......................................................................................... 1-6
Warning on Power Connection ................................................................... 1-7
2. Electrical Alignment
2-1.
2-2.
Preparation .................................................................................................. 2-1
2-1-1. Required Equipment ................................................................... 2-1
2-1-2. Warm-up Time ........................................................................... 2-1
2-1-3. How to Enter Service Mode ....................................................... 2-1
2-1-4. Preparing the Power Supply and Signals ................................... 2-1
White Balance Adjustment ......................................................................... 2-1
3. Troubleshooting
3-1.
3-2.
3-3.
3-4.
3-5.
3-6.
3-7.
Backlight does not light .............................................................................. 3-1
System does not start ................................................................................... 3-2
Operation of this unit is abnormal ............................................................... 3-2
Image is abnormal ....................................................................................... 3-3
TALLY lamp is not lit (LMD-1420 only) ................................................... 3-3
Output function is abnormal ........................................................................ 3-4
Fan is abnormal ........................................................................................... 3-4
4. Spare Parts
4-1.
4-2.
4-3.
4-4.
LMD-1420/1410
Notes on Repair Parts .................................................................................. 4-1
Exploded Views .......................................................................................... 4-2
Electrical Parts List ..................................................................................... 4-4
Packing Materials & Supplied Accessories ................................................ 4-4
1
5. Block Diagrams
Overall ......................................................................................................... 5-1
6. Frame Wiring Diagram
Frame Wiring .............................................................................................. 6-1
2
LMD-1420/1410
Section 1
Service Overview
1-1. Appearance Figure
1-2. Board Location
GA board
X board (LMD-1420 only)
Q board
BA board
S board
Inverter board
H board
J board
LMD-1420/1410
1-1
1-3. Disassembly
1-3-1. Rear Cover
3 Five screws
(PWH4 x 14) 4 Four hooks
8 Rear cover
1 Four screws
(PWH4 x 14)
6 Three hooks
7 Three
hooks
5 Three hooks
2 Stand
Cushion
1-3-2. Q Board
. Remove the rear cover. (Refer to Section 1-3-1.)
1 Two screws
(PWH3 x 6)
3 Three harnesses
2 Harness cover
9 Two screws
(PSW3 x 12)
!/ AC holder
4 Screw
(PSW4 x 8)
7 Two screws
(PWH3 x 6)
5 Harness
8 Q board
6 Two screws
(PWH3 x 6)
!- AC inlet
1-2
Cushion
LMD-1420/1410
1-3-3. GA Board
. Remove the rear cover. (Refer to Section 1-3-1.)
1 Three harnesses
2 Five screws
(PWH3 x 6)
3 GA board
Cushion
1-3-4. Inverter Board/BA Board
. Remove the rear cover. (Refer to Section 1-3-1.)
. Remove the Q board. (Refer to Section 1-3-2.)
2 Frame
1 Five screws
(PWH3 x 6)
6 Ten harnesses
4 Four screws
(PWH3 x 6)
7 Five screws
(PWH3 x 6)
3 Five harnesses
8 BA board
5 Inverter board
Cushion
LMD-1420/1410
1-3
1-3-5. DC Fan/Speaker
. Remove the rear cover. (Refer to Section 1-3-1.)
. Remove the Q board. (Refer to Section 1-3-2.)
Label side
7 Two screws
(P2 x 14)
5 Screw
(PWH3 x 6)
1 Screw
(PWH3 x 6)
8 DC fan
6 Fan bracket
3 Two screws
(P2 x 14)
!/ S board
!- Two screws
(PWH3 x 6)
9 Board holder
4 DC fan
!= Fan bracket
!\ Two screws
(PTP2 x 6)
2 Fan bracket
!] DC fan
!; Speaker
![ Two screws
(B3 x 14)
Cushion
1-3-6. J Board
. Remove the rear cover. (Refer to Section 1-3-1.)
. Remove the Q board. (Refer to Section 1-3-2.)
1 Two screws
(PWH M3 x 8)
3 J board
6 AC cover
2 Harness
5 Three hooks
4 AC button
Cushion
1-4
LMD-1420/1410
1-3-7. LCD Panel
.
.
.
.
.
.
Remove the rear cover. (Refer to Section 1-3-1.)
Remove the Q board. (Refer to Section 1-3-2.)
Remove the GA board. (Refer to Section 1-3-3.)
Remove the inverter board and BA board. (Refer to Section 1-3-4.)
Remove the DC fan and speaker. (Refer to Section 1-3-5.)
Remove the J board. (Refer to Section 1-3-6.)
1 Screw
(PWH3 x 6)
2 Cable retainer
3 Four screws
(PWH M3 x 8)
4 Four screws
(PWH M3 x 8)
5 Main frame
8 LCD panel
!/ Two cushions
9 Two cushions
!- Protection plate
7 Two screws
(PWH3 x 6)
6 Two screws
(PWH3 x 6)
Cushion
LMD-1420/1410
1-5
1-3-8. H Board/X Board (X Board: LMD-1420 only)
.
.
.
.
.
.
.
Remove the rear cover. (Refer to Section 1-3-1.)
Remove the Q board. (Refer to Section 1-3-2.)
Remove the GA board. (Refer to Section 1-3-3.)
Remove the inverter board and BA board. (Refer to Section 1-3-4.)
Remove the DC fan and speaker. (Refer to Section 1-3-5.)
Remove the J board. (Refer to Section 1-3-6.)
Remove the LCD panel. (Refer to Section 1-3-7.)
1 Harness
4 Harness
2 Six screws
(PWH M3 x 8)
3 H board
5 Two screws
(PWH M3 x 8)
6 X baord
(LMD-1420 only)
7 ESD plate
Cushion
1-4. Unleaded Solder
Boards requiring use of unleaded solder are printed with a lead free mark (LF) indicating the solder
contains no lead.
(Caution: Some printed circuit boards may not come printed with the lead free mark due to their particular
size.)
: LEAD FREE MARK
m
. Be sure to use the unleaded solder for the printed circuit board printed with the lead free mark.
. The unleaded solder melts at a temperature about 40 dC higher than the ordinary solder, therefore, it is
recommended to use the soldering iron having a temperature regulator.
. The ordinary soldering iron can be used but the iron tip has to be applied to the solder joint for a
slightly longer time. The printed pattern (copper foil) may peel away if the heated tip is applied for too
long, so be careful.
1-6
LMD-1420/1410
1-5. Warning on Power Connection
Use a proper power cord for your local power supply.
The United States,
Canada
Continental Europe
UK, Ireland, Australia,
New Zealand
Plug type
VM0233
COX-07/636
–1)
Female end
VM0089
COX-02/VM0310B
VM0303B
Cord type
SVT
H05VV-F
CEE (13) 53rd (O, C)
Rated Voltage & Current
10 A/125 V
10 A/250 V
10 A/250 V
Safety approval
UL/CSA
VDE
VDE
1) Use an appropriate rating plug which is applied to local regulations.
LMD-1420/1410
1-7
Section 2
Electrical Alignment
2-1. Preparation
2-2. White Balance Adjustment
2-1-1. Required Equipment
Press “MENU” to display the user menu.
To move the cursor to select an item, use the Up ↑ or
Down ↓ key. To set the selected item, press the “ENTER”
key.
. Luminance meter: If Minolta CA-210, CA-110 or
equivalent.
There is not available, make
adjustment by visually comparing the
LCD monitor with the reference
monitor that has already been
calibrated correctly.
. Signal generator: TG2000 or equivalent
2-1-2. Warm-up Time
Before starting adjustment, allow a warm-up of minimum
120 minutes to stabilize the backlight of the LCD panel.
2-1-3. How to Enter Service Mode
1. Press “MENU” to display the MENU screen.
2. Press the “LINE A” and “ENTER” buttons
simultaneously with MENU screen appeared to enter
the service mode.
2-1-4. Preparing the Power Supply and
Signals
1. Connect the supplied power cord to AC IN of this unit.
Power voltage: 100 to 240 V AC, 50/60 Hz
2. Input the composite signal from the TG2000 to this
unit to display entirely white screen.
3. Turn on the power of this unit. Select the signal that is
used for signal input.
LMD-1420/1410
1. Move the cursor to “WHITE BALANCE” using the
Up ↑ key and press the “ENTER” key to enter the
“COLOR TEMP” layer.
2. After pressing the “ENTER” key, select “USER
SETTING” using the Up ↑ key and press the
“ENTER” key.
HIGH adjustment
Target value: x = 0.283
y = 0.298
1. Set the signal level of the TG2000 to 80IRE.
2. Select “ADJUST GAIN” and adjust the GAIN.
Adjust using “G” and “B” while “R” is fixed.
3. Set the signal level of the TG2000 to 30IRE.
4. Select “ADJUST BIAS” and adjust the BIAS.
Adjust using “G” and “B” while “R” is fixed.
5. Adjust the tracking by steps 3 and 5.
6. Enter the service mode and move the cursor to “TEP”
using the Down ↓ key. Press the “ENTER” key to
enter the “COLOR TEMP” layer.
7. Move the cursor to “C-TEMP SAVE” using the Down
↓ key and press the “ENTER” key. Select “HIGH”
using the Up ↑ key and press the “ENTER” key.
LOW adjustment
Target value: x = 0.313
y = 0.329
1. Set the signal level of the TG2000 to 80IRE.
2. Select “ADJUST GAIN” and adjust the GAIN.
Adjust using “G” and “B” while “R” is fixed.
3. Set the signal level of the TG2000 to 30IRE.
4. Select “ADJUST BIAS” and adjust the BIAS.
Adjust using “G” and “B” while “R” is fixed.
5. Adjust the tracking by steps 3 and 5.
6. Enter the service mode and move the cursor to “TEP”
using the Down ↓ key. Press the “ENTER” key to
enter the “COLOR TEMP” layer.
7. Move the cursor to “C-TEMP SAVE” using the Down
↓ key and press the “ENTER” key. Select “LOW”
using the Up ↑ key and press the “ENTER” key.
2-1
Section 3
Troubleshooting
3-1. Backlight does not light
Backlight does not light.
Are harness
and flexible flat cable
connected correctly?
No
Connect the harness and
flexible flat cable correctly.
Yes
Is the backlight
lit when another BA board
is installed?
Yes
Replace the BA board.
No
Is the backlight
lit when another GA board
is installed?
Yes
Replace the GA board.
No
Replace the LCD panel.
LMD-1420/1410
3-1
3-2. System does not start
System does not start.
Are harness
and flexible flat cable
connected correctly?
No
Connect the harness and
flexible flat cable correctly.
Yes
Is the symptom
improved when another
GA board is installed?
Yes
Replace the GA board.
No
Is the symptom
improved when another
J board is installed?
No
Replace the J board.
Yes
Replace the BA board.
3-3. Operation of this unit is abnormal
Operation of this unit is abnormal.
Are harness
and flexible flat cable
connected correctly?
No
Connect the harness and
flexible flat cable correctly.
Yes
Is the symptom
improved by the external
operation of PARALLEL
REMOTE terminal?
Yes
No
Replace the BA board.
n
For the external operation of PARALLEL REMOTE terminal,
refer to the Operating Instructions.
Replace the H board.
3-2
LMD-1420/1410
3-4. Image is abnormal
Image is abnormal.
Are harness
and flexible flat cable
connected correctly?
No
Connect the harness and
flexible flat cable correctly.
Yes
Is the symptom
improved when another
Q board is installed?
Yes
Replace the Q board.
No
Is the symptom
improved when another
BA board is installed?
Yes
Replace the BA board.
No
Replace the LCD panel.
3-5. TALLY lamp is not lit (LMD-1420 only)
TALLY lamp is not lit.
Are harness and
flexible flat cable connected
correctly?
No
Connect the harness and
flexible flat cable correctly.
Yes
Is the symptom
improved when another
X board is installed?
Yes
Replace the X board.
No
Replace the BA board.
LMD-1420/1410
3-3
3-6. Output function is abnormal
Output function is abnormal.
Replace the Q board.
3-7. Fan is abnormal
Fan is abnormal.
Are harness
and flexible flat cable
connected correctly?
No
Connect the harness and
flexible flat cable correctly.
Yes
Is there any fan that
operates normally?
No
Replace the BA board.
Yes
Replace the abnormal fan.
Yes
Is the symptom improved?
No problem.
No
Is the symptom
improved when another
BA board is installed?
Yes
Replace the BA board.
No
Replace the GA board.
3-4
LMD-1420/1410
Section 4
Spare Parts
4-1. Notes on Repair Parts
1. Safety Related Components Warning
w
Components marked ! are critical to safe operation.
Therefore, specified parts should be used in the case of
replacement.
2. Standardization of Parts
Some repair parts supplied by Sony differ from those
used for the unit. These are because of parts commonality and improvement.
Parts list has the present standardized repair parts.
3. Stock of Parts
Parts marked with “o” at SP (Supply Code) column of
the spare parts list may not be stocked. Therefore, the
delivery date will be delayed.
4. Harness
Harnesses with no part number are not registered as
spare parts.
In need of repair, get components shown in the list and
repair using them.
LMD-1420/1410
4-1
Overall Block
4-2. Exploded Views
PWH4 x 14
PWH4 x 14
PWH4 x 14
14
PWH
3x6
PWH3 x 6
2
PWH3 x 6
19
PWH
3x6
PWH3 x 6
PSW3 x 12
PWH3 x 6
PSW4 x 8
8
PWH3 x 6
11
9
PWH3 x 6
PWH
3x6
PWH3 x 6
PWH3 x 6
PWH
M3 x 8
PWH M3 x 8
B3 x 14
3
PWH M3 x 8
4
PWH3 x 6
P2 x 14
PWH3 x 6
4
PWH3 x 6
P2 x 14
PWH3 x 6
10
12
PWH M3 x 8
17
18
5
18
16
17
PWH3 x 6
PWH3 x 6
PTP2 x 6
13
1
6
PWH M3 x 8
PWH
M3 x 8
PWH M3 x 8
7
15
4-2
LMD-1420/1410
Overall Block
No.
Part No.
1
2
3
4
5
!
!
6
7
9
10
16
17
18
19
X-2050-919-1
X-2050-920-1
X-2055-900-1
1-787-341-11
1-787-342-11
1-789-212-11
s
s
s
s
s
s
BEZEL ASSY (for LMD-1410)
BEZEL ASSY (for LMD-1420)
STAND ASSY
FAN , DC (40 SQUARE)
FAN, DC (35 SQUARE)
MOUNTED CIRCUIT BOARD, X
(for LMD-1420)
1-789-214-11 s MOUNTED CIRCUIT
1-789-228-11 s MOUNTED CIRCUIT
(for LMD-1410)
1-789-215-11 s MOUNTED CIRCUIT
(for LMD-1420)
1-789-229-11 s MOUNTED CIRCUIT
(for LMD-1410)
1-789-213-11 s MOUNTED CIRCUIT
(for LMD-1420)
1-789-263-11 s MOUNTED CIRCUIT
1-789-265-11 s MOUNTED CIRCUIT
8
11
12
13
14
15
SP Description
!
BOARD, J
BOARD, H
BOARD, H
BOARD, Q
BOARD, Q
BOARD, BA
BOARD, S
1-789-266-11
1-805-847-11
1-826-107-11
2-582-179-01
2-590-965-01
s
s
s
s
s
MOUNTED CIRCUIT BOARD, GA
PANEL, LCD
SPEAKER
COVER, REAR
BUTTON, AC SWITCH
2-592-582-01
2-592-583-01
2-592-583-11
2-990-241-02
s
s
s
s
PLATE, PROTECTION (for LMD-1420)
CUSHION (for LMD-1420)
CUSHION (for LMD-1420)
HOLDER (A), PLUG
7-621-772-70
7-681-000-61
7-682-551-09
7-682-903-19
7-682-904-49
s
s
s
s
s
SCREW
SCREW
SCREW
SCREW
SCREW
+B 2X14
+PWH M3X8
+B3X14
+PWH 3X6(EP-FE/ZNBK/CM2)
+PWH 4X14(EP-FE/ZNBK/CM2
7-682-950-09 s SCREW +PSW 3X12(EP-FE/ZNBK/CM2
7-682-961-01 s SCREW +PSW 4X8
7-685-104-19 s SCREW +PTP2X6(EP-FE/ZNBK/CM2)
LMD-1420/1410
4-3
4-4. Packing Materials & Supplied
Accessories
4-3. Electrical Parts List
*1:[LMD-1410]
*2:[LMD-1420]
Ref. No.
or Q'ty Part No.
1pc
1pc
1pc
1pc
1pc
1pc
1pc
4-4
---------------------------------------PACKING MATERIALS & SUPPLIED ACCESSORIES
---------------------------------------Ref. No.
or Q'ty Part No.
SP Description
SP Description
*2 1-789-212-11 s MOUNTED
*2 1-789-213-11 s MOUNTED
*1 1-789-229-11 s MOUNTED
1-789-214-11 s MOUNTED
*2 1-789-215-11 s MOUNTED
*1 1-789-228-11 s MOUNTED
1-789-263-11 s MOUNTED
CIRCUIT
CIRCUIT
CIRCUIT
CIRCUIT
CIRCUIT
CIRCUIT
CIRCUIT
BOARD,
BOARD,
BOARD,
BOARD,
BOARD,
BOARD,
BOARD,
X
Q
Q
J
H
H
BA
1pc
1pc
1pc
1pc
!
2-581-512-01 s CD-ROM
2-590-000-01 s MANUAL, INSTRUCTION
(JAPANESE,ENGLISH)
2-990-242-01 s HOLDER (B),PLUG
------------ CORD, POWER
(See Sec 1-5. Warning on Power Connection)
1-789-265-11 s MOUNTED CIRCUIT BOARD, S
1-789-266-11 s MOUNTED CIRCUIT BOARD, GA
LMD-1420/1410
Overall
Overall
Section 5
Block Diagrams
Q
GA
BA
FLASH
MEMORY
SPEAKER
POWER
BLOCK
L
AMP+DC
FAN
CONTROL
MEMORY
128 x 2
S
SENSOR
YUV422
VIDEO INPUT
PROCESSOR
SYNC
L
LDVS
RECEIVER
ADG779
RX / TX
TALLY_G
TALLY_R
X
TALLY
(FOR LMD-1420)
H
H+V
G/Y
B/Cb
R/Cr
KPD[0..6]
YC
CVBS
FOR APL
CVBS
FOR NTSC
YC
NTSC
3-DIMENSION
DIGITAL
COM FILTER
LCD
PANEL
NS
LVDS
I2C / VCC
5-INPUT 2-OUTPUT AUDIO/VIDEO SW
KEY PAD
LINE B OUT
SDI
L
LINE B IN
YC
CVBS
L
LINE A OUT
L
LINE A IN
CVBS
L
YC
SP232
SDI
L
IN
RGB
L
IN
RGB
L
OUT
RGB IN
RGB OUT
EXT
SYNC
IN
EXT
SYNC
OUT
PARALLEL
REMOTE
8PIN
DIN
Overall
LMD-1420/1410
5-1
5-1
Frame Wiring
Frame Wiring
Section 6
Frame Wiring Diagram
1
J12
J1
SENSOR1
SENSOR2
1
2
3
1
2
J6
SENSOR1
DUMMY
SENSOR2
GND
GND
RXIN1+
LCD_5V
RXIN1_
LCD_5V
GND
GND
RXIN2+
RXCLKIN+
RXIN2_
RXCLKIN_
GND
GND
RXIN3+
RXIN0+
RXIN3_
RXIN0_
GND
GND
S
CN701
CN601
1
2
J
N
L
GA
+12V
+12V
GND
GND
VCC
+9V
VCC
VCC
GND
GND
NC
GND
LCD_ON
LCD_BR
J8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
+12V
+12V
GND
GND
VCC
+9V
VCC
VCC
GND
GND
NC
GND
LCD_ON
LCD_BR
1
2
3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
GND
GND
RXIN1+
LCD_5V
RXIN1_
LCD_5V
GND
GND
RXIN2+
RXCLKIN+
RXIN2_
RXCLKIN_
GND
GND
RXIN3+
RXIN0+
RXIN3_
RXIN0_
GND
GND
LCD
PANEL
2
CN702
INVERTER
BOARD
19V
19V
GND
LCD_BR
GND
LCD_ON
GND
1
2
3
4
5
6
7
1
2
3
4
5
6
7
19V
19V
GND
LCD_BR
GND
LCD_ON
GND
J1
J2
BA
GND
R_J2
G_J2
1
2
3
1
2
3
J5
SPEAKER
J1
J27
J26
1
2
CVBS_PAL
GND
S_Y
S_C
GND
G_COMP_Y_IN
R_COMP_CR_IN
B_COMP_CR_IN
GND
EXT_SYNC_IN
GND
SDA_1
SCL_1
SYS_MUTE
AUD_VOL
AUD_OUT+
AUD_OUT_
INT_I/O
GND
SCL_KEYPAD
SDA_KEYPAD
GND
V33_KEYPAD
V33_KEYPAD
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1 CVBS_PAL
2 GND
3 S_Y
4 S_C
5 GND
6 G_COMP_Y_IN
7 R_COMP_CR_IN
8 B_COMP_CR_IN
9 GND
10 EXT_SYNC_IN
11 GND
12 SDA_1
13 SCL_1
14 SYS_MUTE
15 AUD_VOL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
J24
J4
4
FAN2
1
2
3
FAN3
J11
12V_FAN1
FANSPIN1_2
GND
H
FAN1
J10
12V_FAN1
FANSPIN1_1
GND
KPD0
KPD1
KPD2
KPD3
KPD4
KPD5
KPD6
GND
TXD
RX
GND
SDI_EN
VCC
+9V
3
1
2
3
4
Q
KPD0
KPD1
KPD2
KPD3
KPD4
KPD5
KPD6
GND
TXD
RX
GND
SDI_EN
VCC
+9V
X
(FOR LMD-1420)
J1
1 INT_I/O
2 GND
3 SCL_KEYPAD
4 SDA_KEYPAD
5 GND
6 V33_KEYPAD
7 V33_KEYPAD
1
2
3
4
5
6
7
J9
12V_FAN2
FANSPIN2
GND
GND
GND
R_J2
G_J2
5
1
2
3
Frame Wiring
6-1
LMD-1420/1410
A
B
C
D
6-1
E
F
G
H
SAFETY CHECK-OUT
After correcting the original service problem,
perform the following safety checks before
releasing the set to the customer :
Check the metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC
leakage. Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to
any exposed metal part having a return to
chassis, must not exceed 0.5 mA. Leakage
current can be measured by any one of three
methods.
1. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers’ instructions to use these
instruments.
2. A battery-operated AC milliammeter. The
Data Precision 245 digital multimeter is
suitable for this job.
3. Measuring the voltage drop across a resistor
by means of a VOM or battery-operated AC
voltmeter. The “limit” indication is 0.75 V, so
analog meters must have an accurate lowvoltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM
that is suitable. Nearly all battery operated
digital multimeters that have a 2 V AC range
are suitable. (See Fig. A)
To Exposed Metal
Parts on Set
0.15 µF
1.5 kZ
AC
voltmeter
(0.75V)
Earth Ground
Fig A. Using an AC voltmeter to check AC leakage.
LMD-1420/1410
LMD-1420 (SY)
LMD-1410 (SY) E
9-968-137-01
Sony Corporation
B&P Company
Printed in Japan
2005. 3 22
©2005