DOWNLOAD LG 42PC55-ZB (CHASSIS:PD73A) Service Manual ↓ Size: 13.57 MB | Pages: 53 in PDF or view online for FREE

- 21 -

ANALOG & DIGITAL BOARD

PDP MODULE

READY

CN1

P1

P2

P3

P11

P12

P21

P22

AC INLET

AC

NC

AC

SMW250-013P

AC Det

RL-ON

STB 5V

GND

Vs-ON

5V Det

M5V-ON

STB 5V

GND

NC

6V

GND

3.4V-ON

SMW250-13P

19V

19V

GND

GND

6V

GND

3.4V

GND

12V

GND

SMW250-10P

3.4V

3.4V

GND

GND

6V

6V

GND

GND

12V

12V

GND

GND

SMW250-12P

Vs

Vs

NC

GND

GND

Va

GND

5V

YH396-08V

5V

GND

Va

GND

GND

GND

NC

Vs

Vs

YH396-09V

5V

5V

GND

GND

YH396-04V

GND

GND

GND

GND

5V

5V

5V

5V

SMW250-08P

1

2

3

4

5

6

7

8

9

10

11

12

13

Wafer P/N

NO

- 22 -

1) Does not  minute discharge at module. 
2) Non does not come into the front LED. 

Is the power cord plugged in?

Plug in the power cord.

Yes

No

Is the Line Filter and Power

Board Cable connected?

Connect the Cable.

Yes

No

Is the appropriate Fuse(F101) on

the Power Board?

Replace the Fuse.

Yes

No

Is the Power Board and 13P of

VSC Board Cable connected?

Connect the Cable.

Yes

No

After removing the cables, connect them to the Power Board(except the
SC101 connection cable), and change the AC voltage marking to manual.
When ST-BY 5V does not operate, replace the Power Board.

- 23 -

1) After lighting up once, it does not discharge 

minutely from module.

2) The rely falls.(there is an audible “click”) 
3) The color of the front LED turns from green to red.

Is the Power Board

normal ?

Replace the Power Board.

Is the output Low/High voltage normal

except for Stand-by 5V?

Yes

No

No

Is the each connector

normal?

Replace the connector.

Replace the 

Y-Board.

After connecting each connector do

they operate normally? 

Yes

No

Yes

Is the Ctrl Board

normal?

Replace the 

X-Board.

Is the output voltage normal after

removing P1, 2, 4, 9, 10 connectors of

the Ctrl-B/D?

Yes

No

Yes

Is the Y-Board

normal?

Is the output voltage

normal after removing

P103 connector of 

Y-B/D?

Is the appropriate Fuse(FS101,FS102)

on the Y-B/D normal?(Replace if open)

Yes

No

Yes

Yes

Replace the 

Z-Board.

Is the Z-Board

normal?

Is the output voltage

normal after removing

P1 connector of

Z-B/D?

Is the appropriate Fuse (FS1, FS2) on

Z-B/D? (replace if open)

Yes

No

Yes

Is the X- Board

normal?

Is the output voltage normal after

removing P1, 2, 3, 4, 5 connectors of

the X-B/D?

If the output voltage is normal after removing
the P1, P2, P3 : Replace the right X-B/D
If the output voltage is normal after removing
the P4, P5 : Replace the left X-B/D

Yes

No

Yes

Is the 

VSC Board normal?

Is the output voltage normal after

removing P900, P901 of VSC Board?

After a COF crisis for each board, check the normal operation. For normal operation,
corresponding COF failure means the module should be relaced.

If it operates normally after removing the
P900, P901 : Replace the VSC Board

Yes

No

Is the COF of X, Y, Z

normal ?

No

Yes

Yes

- 24 -

Does minute discharge

At Module?

Is the LVDC cable

normal?

Is the VAVS on?

Check the PDP Module

Yes

No

YES

Yes

Reconnect the LVDS

cable in P800

No

Is the IC700(FLI8548)

Output normal?

Replace the VSC.

No

NO

Replace the Power

board

Is the Low/High output

voltage normal except for

stand-by 5V?

NO

1) No OSD and image occur at screen. 
2) It maintains the condition where the front LED is green.