LG 42PQ20D User manual

PLASMA TV
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CHASSIS : PA91A
MODEL : 42PQ20D 42PQ20D-AA
North/Latin America http://aic.lgservice.com
Europe/Africa http://eic.lgservice.com
Asia/Oceania http://biz.lgservice.com
Internal Use Only

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Only for training and service purposes
CONTENTS
CONTENTS ............................................................................................................................... 2
SAFETY PRECAUTIONS...........................................................................................................3
SPECIFICATION.........................................................................................................................4
ADJUSTMENT INSTRUCTION..................................................................................................6
BLOCK DIAGRAM ...................................................................................................................10
EXPLODED VIEW ....................................................................................................................11
SVC. SHEET ................................................................................................................................
PRINTED CIRCUIT DIAGRAM.....................................................................................................

- 3 - LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
SAFETY PRECAUTIONS
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Exploded View.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance
An isolation Transformer should always be used during the
servicing of a receiver whose chassis is not isolated from the AC
power line. Use a transformer of adequate power rating as this
protects the technician from accidents resulting in personal injury
from electrical shocks.
It will also protect the receiver and it's components from being
damaged by accidental shorts of the circuitry that may be
inadvertently introduced during the service operation.
If any fuse (or Fusible Resistor) in this monitor is blown, replace it
with the specified.
When replacing a high wattage resistor (Oxide Metal Film Resistor,
over 1W), keep the resistor 10mm away from PCB.
Keep wires away from high voltage or high temperature parts.
Due to high vacuum and large surface area of picture tube,
extreme care should be used in handling the Picture Tube.
Do not lift the Picture tube by it's Neck.
Leakage Current Cold Check(Antenna Cold Check)
With the instrument AC plug removed from AC source, connect an
electrical jumper across the two AC plug prongs. Place the AC
switch in the on position, connect one lead of ohm-meter to the AC
plug prongs tied together and touch other ohm-meter lead in turn to
each exposed metallic parts such as antenna terminals, phone
jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1MΩand 5.2MΩ.
When the exposed metal has no return path to the chassis the
reading must be infinite.
An other abnormality exists that must be corrected before the
receiver is returned to the customer.
Leakage Current Hot Check (See below Figure)
Plug the AC cord directly into the AC outlet.
Do not use a line Isolation Transformer during this check.
Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.)
and the exposed metallic parts.
Measure the AC voltage across the resistor using AC voltmeter
with 1000 ohms/volt or more sensitivity.
Reverse plug the AC cord into the AC outlet and repeat AC voltage
measurements for each exposed metallic part. Any voltage
measured must not exceed 0.75 volt RMS which is corresponds to
0.5mA.
In case any measurement is out of the limits specified, there is
possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.
Leakage Current Hot Check circuit
1.5 Kohm/10W
To Instrument's
exposed
METALLIC PARTS
Good Earth Ground
such as WATER PIPE,
CONDUIT etc.
AC Volt-meter
IMPORTANT SAFETY NOTICE
0.15uF

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Only for training and service purposes
SPECIFICATIONS
NOTE : Specifications and others are subject to change without notice for improvement .
VApplication Range
This spec is applied to 42”/50” PDP TV used PA91A Chassis.
V Specification
Each part is tested as below without special appointment.
1) Temperature : 25±5°C (77±9°F), CST : 40±5
2) Relative Humidity: 65±10%
3) Power Voltage: Standard Input voltage (100-240V~, 50/60Hz)
* Standard Voltage of each product is marked by models.
4) Specification and performance of each parts are followed each drawing and specification by part number in accordance with SBOM.
5) The receiver must be operated for about 20 minutes prior to the adjustment.
VTest Method
1) Performance : LGE TV test method followed.
2) Demanded other specification
Safety : CB specification
EMC : CISPR 13 specification
VModule Specification
(1) 50”
Chassis
PA91A 50PQ60D-AA
42PQ60D-AA
50PQ20D-AA
42PQ20D-AA
Australia LG
Model Name Market Brand Remark
Model Name
50PQ60D-AA
42PQ60D-AA
50PQ20D-AA
42PQ20D-AA
Remark
Safety : IEC60065,
EN60065
EMC : CISPR 13 Class B
Market
Australia
Appliance
TEST
Display Screen Device
Aspect Ratio
PDP Module
Operating Environment
Storage Environment
Input Voltage
1
2
3
4
5
6
No Item Specification Remark
50 inch wide Color Display Module
16:9
PDP50XG2####,
RGB Closed Type
1) Temp. : 0 ~ 40deg
2) Humidity : 20 ~ 80%
3) Temp. : -20 ~ 60deg
4) Humidity : 10 ~ 90%
AC100-240V~, 50/60Hz
PDP
LGE SPEC.
Maker: LG

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Only for training and service purposes
(2) 42”
VModel General Specification
Display Screen Device
Aspect Ratio
PDP Module
Operating Environment
Storage Environment
Input Voltage
1
2
3
4
5
6
No Item Specification Remark
42 inch wide Color Display Module
16:9
PDP42XG2####,
RGB Closed Type
1) Temp. : 0 ~ 40deg
2) Humidity : 20 ~ 80%
3) Temp. : -20 ~ 60deg
4) Humidity : 10 ~ 90%
AC100-240V~, 50/60Hz
PDP
LGE SPEC.
Maker: LG
Market
Broadcasting system
Receiving system
Video Input (1EA)
S-Video Input (1EA)
Component Input (2EA)
RGB Input(1EA)
HDMI Input(3EA)
Audio Input (5EA)
Audio Out(1EA)
USB(1EA)
1
2
3
4
5
6
7
8
9
10
11
No Item Specification Remark
Australia
1) PAL-BG
2) DVB T
Analog : Upper Heterodyne
Digital : COFDM
PAL, NTSC
PAL, NTSC
Y/Cb/Cr, Y/Pb/Pr
RGB-PC
HDMI-DTV & SOUND
PC Audio, Component(2EA), AV(2EA)
SPDIF(1EA)
Divx, MP3, JPEG
L/R Input(PC 1EA, SIDE AV 1EA,
Component 2EA, Rear AV 1EA)
DIVX, MP3, JPEG ONLY FOR PQ60

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Only for training and service purposes
ADJUSTMENT INSTRUCTION
1. Application Range
This spec sheet is applied all of the PDP TV, PA91A chassis.
2. Specification.
(1) Because this is not a hot chassis, it is not necessary to use
an isolation transformer. However, the use of isolation
transformer will help protect test instrument.
(2) Adjustment must be done in the correct order.
(3) The adjustment must be performed in the circumstance of
25±5°C of temperature and 65±10% of relative humidity if
there is no specific designation.
(4) The input voltage of the receiver must keep 100~240V,
50/60Hz.
(5) The receiver must be operated for about 5 minutes prior to
the adjustment when module is in the circumstance of over
15°
- In case of keeping module is in the circumstance of 0°C,
it should be placed in the circumstance of above 15°C for
2 hours
- In case of keeping module is in the circumstance of below
-20°C, it should be placed in the circumstance of above
15°C for 3 hours,.
OAfter RGB Full White in HEAT-RUN Mode, the receiver
must be operated prior to the adjustment.
OEnter into HEAT-RUN MODE
(1) Press the POWER ON KEY on R/C for adjustment.
(2) OSD display and screen display PATTERN MODE.
* Set is activated HEAT run without signal generator in this
mode.
* Single color pattern (WHITE) of HEAT RUN MODE uses to
check panel.
Caution: If you turn on a still screen more than 20 minutes
(Especially digital pattern, cross hatch pattern), an
after image may be occur in the black level part of the
screen.
Caution: Using ‘power on’ button of the control R/C, power on
TV.
OAuto-control adjustment protocol(RS-232C)
3. Insert Tool OPTION and Model
Name Download
(1) Press IN_START key on R/C to insert Tool OPTION
(2) On the “Tool Option 1”, Insert Tool Option by a number
key
(3) Press the ENTER(V)
(4) Press ENTER(V) again.
(5) Select “OK to Download” by using F/G(VOL +/-) and press
G(VOL +)

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Only for training and service purposes
4. EDID(The Extended Display
Identification Data) Download
(1) Press the ADJ KEY on R/C and enter EZ ADJUST.
(2) Select “5.EDID D/L” by using D/E(CH +/-) and press
ENTER(V).
(3) Select “Start” and press navigation key(G).
(4) EDID download is executed automatically.
(5) Press EXIT key on R/C
(6) EDID DATA
1) Analog RGB
ODetail EDID Options are below (ⓐ, ⓑ, ⓒ, ⓓ)
ⓐProduct ID
ⓑWeek, Year
=> Controlled on production line:
ex) Week: ‘03’ -> ‘03’
Year: ‘2006’ -> ‘10’
ⓒModel Name(Hex)
ⓓChecksum: Changeable by total EDID data.
2) HDMI
ODetail EDID Options are below (ⓐ, ⓑ, ⓒ, ⓓ, ⓔ)
ⓐProduct ID
ⓑWeek, Year
=> Controlled on production line:
ex) Week: ‘03’ -> ‘03’
Year: ‘2006’ -> ‘10’
ⓒModel Name(Hex)
ⓓChecksum: Changeable by total EDID data.
ⓔVender ID

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Only for training and service purposes
5. ADC Adjustment
5-1. Adjustment of RGB
Auto RGB Gain/Offset Adjustment
(1) Convert to PC in Input-source.
(2) Signal equipment displays
Output Voltage: 700 mVp-p
Impress Resolution XGA (1024 x 768 @ 60Hz)
Model : 60 in Pattern Generator
Pattern : 65 in Pattern Generator (MSPG-925 SERISE)
3) Adjust by commanding AUTO_COLOR_ADJUST
5-2. Adjustment of COMPONENT
Component Gain/Offset Adjustment
(1) Convert to Component in Input-source.
(2) Signal equipment displays
Impress Resolution 480i
MODEL: 209 in Pattern Generator(480i Mode)
PATTERN : 65 in Pattern Generator(MSPG-925 SERISE)
Impress Resolution 1080i
MODEL: 223 in Pattern Generator(1080i Mode)
PATTERN: 65 in Pattern Generator(MSPG-925 SERISE)
5-3. Confirmation
Press ‘InStart’ Key on Factory SVC Remote Controller, It is
possible to check ADC & EDID ADJ
Caution: Each PCB assembly must be checked by check JIG
set.
(Because power PCB Assembly damages to PDP
Module, especially be careful)
6. POWER PCB Assembly Voltage
Adjustment(Va, Vs voltage Adjustment)
6-1. Test Equipment:D.M.M 1EA
6-2. Connection Diagram for Measuring:
Refer to fig.1
6-3. Adjustment Method
(1) Va adjustment
1) Connect + terminal of D. M.M. to Va pin of P811, connect -
terminal to GND pin of P811.
2) After turning VR901,voltage of D.M.M adjustment as same
as Va voltage which on label of panel right/top (deviation;
±0.5V)
(2) Vs adjustment
1) Connect + terminal of D. M..M. to Vs pin of P811, connect
-terminal to GND pin of P811.
2) After turning VR951, voltage of D.M.M adjustment as same
as Vs voltage which on label of panel right/top (deviation ;
±0.5V)
7. Download Serial Number (RS-232C)
(1) Press “Power on” key of service R/C.(Baud rate : 115200
bps)
(2) Connect RS232 Signal Cable to RS-232 Jack.
(3) Write Serial number by use RS-232.
(4) Must check the serial number at the Diagnostics of SET
UP menu.
(Refer to below ‘6.SET INFORMATION’).

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8. Adjustment of White Balance
8-1. Required Equipment
(1) Remote controller for adjustment
(2) Color Analyzer (CS-1000, CA-100,100+,CA-210 or same
product) : CH 10 (PDP)
[Please adjust CA-210, CA-100+ by CS-1000 before
measuring
(3) Auto W/B adjustment instrument(only for Auto adjustment)
(4) 9 Pin D-Sub Jack(RS232C) is connected to the AUTO W/B
EQUIPMENT.
8-2. AUTO White Balance Process
Before Adjust of White Balance, Please press POWER ONLY
key
Adjust Process will start by execute RS232C Command
OColor temperature standards according to CSM and Module
OCS-1000/CA-100+/CA-210(CH 10) White balance
adjustment coordinates and color temperature.
8-3. Manual W/B Process (using adjusts Remote control)
Please Adjust in AV 1 MODE, Turn off Energy Saving Mode.
(1) Enter “PICTURE RESET” on Picture Mode, then turn off
Fresh Contrast and Fresh colour in Advanced Control
(2) After enter Service Mode by pushing “ADJ” key,
(3) Enter White Pattern off of service mode, and change off ->
on.
(4) Enter “W/B ADJUST” by pushing “G” key at “3. W/B
ADJUST”.
(5) Adjust W/B DATA, for all CSM, choose ‘COPY ALL’
[Gain Max Value is 192. So, Never make any Gain Value
over 192 and please fix one Value on 192, between R, G
and B.
8-4. Auto-control Interface and Directions
(1) Adjust in the place where the influx of light like floodlight
around is blocked.
(Illumination is less than 10ux).
(2) Measure and adjust after sticking the Color Analyzer (CA-
100+, CA210 ) to the side of the module.
(3) Aging time
After aging start, keep the Power on (no suspension of
power supply) and heat-run over 5 minutes
8-5.
Auto Adjustment Map(RS232C)
9. Checking the EYE-Q Operation
(1) Press the EYE Key on the adjustment remote controller.
(2) Check the Sensor DATA (It must be under 10) and keep
the data longer than 1.5s
(3) Check ‘OK’
(Sensor DATA 0 ~ 4095, Power Saving Mode 0 ~ 12)
[IF you press IN-STAP Button, change Green Eye-check OSD.
PLASMA Remark
11000K
9300K
6500K
Cool
Medium
Warm
CSM
Color Coordinate
xy
0.283
0.293
0.329
11,000K
9,300K
6,500K
0.002
0.002
0.002
0.276
0.285
0.313
Cool
Medium
Warm
CSM Temp ±Color
Coordinate

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Only for training and service purposes
BLOCK DIAGRAM

A10
900
901
400
520
590
240
250
300
305
301
303
302 200
120
580
260
270 603 602 601
501
A2
LV1
570
560
561
310
330
201
203
205
204
206
202
- 11 - LGE Internal Use Only
EXPLODED VIEW
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These
parts are identified by in the Schematic Diagram and EXPLODED VIEW.
It is essential that these special safety parts should be replaced with the same components as
recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
IMPORTANT SAFETY NOTICE

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LGE Internal Use OnlyCopyright©2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes