LG Plasma Schematic

PDP One Point Repair Guide

General

40 ~ 50 Inch Practice

60 Inch Practice

Symptom Cause

(Bad X-Board PCB)

Countermeasure

Change X board

Red Bar at left lower

CHECK Point

1. Check after X-Board change

2. Do shortage check neighboring pins of FPC* connector

3. Check soldering condition of defect pin

4. Scan the pattern connected to defect pin with Microscpoe

2/88

PCB Pattern Short

*FPC : Flat Pin Connector

LG Electronics / DND / QA Gr.

Symptom

Cause

Countermeasure

PCB

Red & Green pin of left lower 4th FPC short

Defect Point : Short on the PCB just above connector

1. Cause : Short by solder bridge

- Can not observe with naked eye

- When connector open, pattern is OK

Check Point

1. Check the contact status with connector(foreign material, soldering condition)

2. Replace X Board and check again.(If OK, X-Board is defected)

Change X-Board

3. By tracing defected line, check the contact condition of FPC and other connectors, IC output stage and PCB pattern.

4. If no problem, check the connector lead board.

3/88

LG Electronics / DND / QA Gr.

Symptom Cause

Countermeasure

Pattern Short by connector miss insert

Bottom Right 6th FPC R/B Short

Check Point

1. Check the contact status with connector(foreign material, soldering condition)

2. Replace X Board and check again.(If OK, X-Board is defected)

3. By tracing defected line, check the contact condition of FPC and other connectors, IC output stage and PCB pattern.

4. If no problem, check the connector lead board.

Re-insert the Connector

4/88

LG Electronics / DND / QA Gr.

SHORT

Symptom Cause

Foreign Material(Iron powder) in the Connector

Gap

Countermeasure

X-Board Tape Rework

Insulation tape

ADD Electrode short at R,G,B Raster or White Screen(Different color display)

▶ Apply silicon on the Connector lead ←Pay attention to a capillary symptom

↓

Check Point

1. Trace defected line

2. Check the condition of FPC and connector on the X-Board, IC Output stage and Electrode line.

5/88

LG Electronics / DND / QA Gr.

Symptom Cause

OPEN

1. Outbreak during heat run

2. ADD Electrode open at one color Raster or White screen(No discharge)

Keep horizontal, or can be defected

Interfere with mechanical structure when Module assembling

Cold soldering at Connector

▶ Use Connector fixing iron plate ⇒ Keep the contact point horizontal when interfere with mechanical parts

Countermeasure

FPC connector Rework

Check Point

1. Trace defected line and check the condition of FPC and connector on X-Board, IC Output stage and Electrode line.

6/88

LG Electronics / DND / QA Gr.

Symptom Cause

Countermeasure

ADD Pattern

Connected minutely and open slowly as time passes

ADD open

Check Point

1. Replace X Board and check again(Still problem, change the Panel)

2. Check the connection status of Panel side.

3. Check the connection condition of connector of Panel side and the FPC at upper ACF. → If it is OK, check Panel pad

Replace the Panel

7/88

LG Electronics / DND / QA Gr.

CountermeasureSymptom & Cause

ADD Electrode open

at Green Raster

16pin

1,3,15,17,19pin

Resistance A Resistance B

1.2Ω 6.0Ω

1.0 ~1.2Ω 2.2~2.4Ω

Panel Electrode

ACF

Open Electrode(16)

1. ADD pattern of PAD siden open

2. Width : 10 um

Resistance B

FPC

Electrode

Resistance A

Check Point

1. Check the connection condition - Press the connector and reconnect

2. Check the soldering condition of Connector lead

3. Replace X Board and check again; Panel connector side or Circuit connector side → Board defect, in case of one line, check the output stage of Drive IC(Cold soldering/Pattern) If problems in input stage, several lines display

Replace the Panel

* The difference of ADD open and Short ? ADD open : Black vertical bar at Raster ADD short : Different color vertical bar at Raster

8/88

LG Electronics / DND / QA Gr.

Symptom Cause

Control board

Countermeasure

Con 2

X-board

Solder bridge

< Raster >

Con 1

< White >

ADD short at raster screen and ADD open at white screen appear at some area after 20 minute HeatRun.

Check Point

1. Check the 5V(Logic voltage) input to DC-DC → If it is lower than 5V, it makes similar problem

2. Check X Board(Open or Short circuit)

3. Check the connection condition(conncetion status, foreign material at connector, etc)

4. Check the drive IC at X Board(If defected, change the Board)

5. Confirm the connection of the connector

Change Control Board

9/88

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Symptom Cause

Countermeasure

Change X-BOARD

X-DRV IC

CLK LE

PCB pattern short

Check Point

Driver clock line at X Driver Board is designed to operate in A and B group ▶ Short circuit at clock line of Drive IC ▶ If problem at input stage, several lines are defected at one point ▶ Replace the X Board of defected point

10/88

R264 R258

SN74ACT541

Short

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Symptom Cause

<X-board>

Countermeasure

connector

▶ PCB pattern is connected minutely → Foreign material when photo resisting

Check Point

1. Check the connection condition of the Connector.

2. Check the cold soldering.

Electrode

Pattern

Chip

Resistors

4X16

= 64 data

(SN755851PJ)

line1 line2

line3 line4

X driver

chip

16 clock

o d u

Change

X Board

11/88

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Symptom Cause

Resistance between 186 pin of U3 and 7 pin of U300 is 62 Ω Normal condition : 2Ω

Countermeasure

Because of foreign material in Via hole at U300 side

Via hole

U300

DRAM

7pin PIN

Vertical bar in every 20mm

ALTERA Chip

186pin PIN

Control board

Check Point

1. Measure the resistance of Via holes between U3 and U300 at Control Board and compare with that of normal.(Normal : 2~3 Ω)

2. Resistance increases as temperature rises.

Change Control Board

12/88

LG Electronics / DND / QA Gr.

Symptom Cause

- Open circuit between pin 7 of U200 and pin 7 of U7

- Resistance between two pins varies from 19 ohm ~ 45Kohm

Countermeasure

Replace Control Board

Check Point

1. Observe the symptom during Heat-Run at 45 degree.

2. Check the resistance of VIA holes of suspect ICs

13/88

LG Electronics / DND / QA Gr.

Symptom Cause

- When Power On, Fan operates but No OSD displays

- LED(D3) of Control Board doesn’t operate

D1 D3

FPGA

CONTROL BOARD

PROM(U40)

Countermeasure

1. Because Control data on PROM(U40) doesn’t download to FPGA, it can’t generate control signal to X,Y and Z Board.

2. Defected ALTERA.

•Replace Control Board

•Replace PROM

* For normal operation, PROM program should be downloaded to FPGA, and each PROM has corr espondent FPGA. See left picture.

Check Point

1. Check D1, D3 & D4 on Control Board

- D1 : ON with 5V

- D3 : ON when PROM finishes program download from ALTERA chip

- D4 : ON when signal is applied

14/88

LG Electronics / DND / QA Gr.

Symptom Cause

Control Board

Touch point(Marked)

Countermeasure

Replace Controller board

No signal or at PC mode, dark red raster displays. This is darker than normal Red signal.

Check Point

- TV VSC board

- Board connector(50 pin) contact point

- Control board of Module

▶ Neighboring Pins of U1(FPGA) touch

15/88

LG Electronics / DND / QA Gr.

Symptoms Cause

1. CN1 on Vs Board cold soldering

2. Spark marks between CN1 and Vs Board

-> It makes them open

Countermeasure

Replace DC-DC 2 board

Soldering Direction

CN1

Vs board

Solder land

1. No Raster(ST-BY LED On)

2. Spark noise(Tik-Tik)

3. No Vs, Vsetup & Vsc

Check Point

1. Check Vs, Va with multimeter(No Vs output)

2. Separate SMPS Board and VSC Board and check all voltage output stage

3. Check FET, TR, Diode and Resistor(especially Cement Resistor)

4. Observe PCB Pattern and soldering condition with naked eyes

Soldering point

Solder

Soldering Direction

16/88

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40 ~ 42 Inch

42 Inch

42” PDP Flicker and

No Raster Troubleshooting

Guide

cause : bad connection between Y-Board # 1, 2 drive board Connector pin

Rework should be done

Y-Board

Y-Driver Board

LG Electronics / DND / QA Gr.

②

P 6

①

②

amplified

②

① : outside Leg ② : inside Leg

•P 6, P 4 both are the first pin, when

wiring, it should be done as picture shown. (bend the wire to Y-Driver B/D not to Y-B/D . If not there can be noise)

•Don’t be confused with Pin number

•Improved since Dec,2001.

①

P 4

①

②

①

amplified

①

②

LG Electronics / DND / QA Gr.

②

①

②

①

Be sure not to misconnect the line. See the picture precisely and then connect jump wire at the exact point

①

②

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Intermittent no-image/image error while watching

CANVAS

The screen is intermittently disappeared . LED is green

cause : bad connection between Y-Board and #1, 2 pin of Y-Drive Board Connector

CANVAS

screen is distorted weiderly (happened 2 a day)

CANVAS

troubleshooting : connect bad linking between Y-Board & Y-Drive with jump wire (all 4 parts)

see working instruction(revised since Dec,2001.

normal

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No Power

CANVAS

No Power ( in ST-BY mode, but no LED)

Check the power supply & main power S/W on

CANVAS

normal

Check EMI board fuse (check the rated capacity )

Be sure to use rated fuse.

Fuse 15 A

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No Raster

CANVAS

when Power’s on, after 2 ~ 3 sec, it’s off ( LED changing green into red )

CHECK : remove STB and operate monitor individually. (check STB defect or Monitor defect )

CANVAS

normal

When using ANALOG STB, check STB only MN-42PZ10 only STB : RN-BA11

Remove each Board’s power supply connector and check the power is off. When the power is not off,replace the related board.

LG Electronics / DND / QA Gr.

CANVAS

No Picture

no picture (LED’s green)

Core checkpoint : remove STB and operate monitor individually. (check whether STB’s a defect or monitor’s one)

With monitor defect, check VSC and then Controller Board.

Troubleshooting : replace VSC Board

normal

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Address Bar ( Horizontal Bar )

CANVAS

no image (LED’s green)

Cause : Y-Drive ( Bottom ) defect

CANVAS

normal

Troubleshooting : Y-Drive (lower part) replacement

This problem is shown in the bottom of screen, So it is caused by Y-Drive

Y-Drive Board ( Bottom )

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Address Bar ( Horizontal Bar )

CANVAS

no image (LED’s green)

Cause : Y-Drive Board (upper part) defect

CANVAS

normal

Y-Drive Board ( Top )

Troubleshooting : Y-Drive Board replacement

LG Electronics / DND / QA Gr.

CANVAS

No Picture

no image (LED’s green)

cause : PD-501 Connector contact point defect

troubleshooting : PD-501 Connector replacement

(with PD-501 Connector contact point defect, Various defect symptoms can be seen)

normal

PD501 Connector

LG Electronics / DND / QA Gr.

High frequency noise (“Bee” sound)

CANVAS

normal picture with high frequency noise (“bee”)

SMPS is supposed to operate with high frequency so small noise is not considered as a defect.

CANVAS

normal

Power (SMPS) Board

1. C8178 0.22㎌/50V add

2. Open C8139 right lead, and then connect it to R8164 right lead.

C8178 0.22uF electrolytic

Improved since Nov,2001

capacitor insertion

#. Slight noise is not a defect and write down explanation

Open C8139 right lead and then wire R8164 right lead

LG Electronics / DND / QA Gr.

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