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LAMP

SORCE DRIVER

DISPLAY UNIT

LCD MODULE UNIT

GATE DR

IVER

INTERFACE 

UNIT

INVERTER

LAMP

LCD PANEL

KEY-SWITCH UNIT

BRIGHTNESS

SENSOR UNIT

DC CONNECTOR

RGA,H/V

INPUT

[FROM PC]

AC

ADAPTER

[AC INPUT]

Pin No.

Symbol

Description

1

NC

2

NC

3

GND

Ground

4

GND

Ground

5

12V

+12Vdc

6

12V

+12Vdc

Pin No.

Symbol

Description

1

GND

Ground

2

R

Analog Red

3

GND

Ground

4

G

Analog Green

5

GND

Ground

6

B

Analog Blue

7

GND

Ground

8

HSY

Horizontal Sync

9

VSY

Vertical Sync

10

5V

+5Vdc

11

SDL

DDC Serial Data

12

SCL

DDC Data Clock

Pin No.

Symbol

Description

1

Signal input

Sensor Signal Input

2

5V

+5Vdc

Pin No.

Symbol

Description

1

POWER SW

ON/OFF

2

GND

Ground

3

LED2

LED control signal

4

LED1

+5V

5

SW4

6

SW3

UP

7

SW2

DOWN

8

SW1

+

Pin No.

Symbol

Description

1

CBKLT

0/3.3Vdc (High Active) 

2

NC

3

CBTNS

0.0 ~ 3.5Vdc

4

GND

Ground

5

12V

+12Vdc Input

No power supply

Does LED turns on in green 
when power switch is turned 
on?

No

No

No

No

No

No

LED turns on in red?

Yes

Yes

Yes

Yes

Yes

*  Check LED for breakage.
*  Check the path between J101 (Pin 3) 

and IC101 (Pin 16).

*  Check cable for disconnection.

Replace any unit (main PWB, SW PWB, cable) 
which shows any defect, with a new one.

1) PC is turned off?
2) RGB cable is disconnected?
3) Synchronizing signal is output from RGB 

cable?

Check whether the unit is in power save 
mode (synchronizing signal is not input.).

Synchronizing signal is input to main PWB?

Replace RGB cable 
with a new one.

LED turns on in orange?

Check power input system.

1) AC adapter
   *  Normal?
   *  Connected properly?
2) Blown out fuse (FU501)?
3) EEPROM (IC103) has +5V (VCC)?
4) LED
   *  Check LED for breakage.
   *  Check the path between J101 (Pin 3) 

and IC101 (Pin 16).

   *  Check the cable for disconnection.

Replace any defective unit.
[ 1) Adapter, 2) A Main PWB, 3) Switch 
PWB ] with a new one.

Backlight turns ON?

Check for RGB cable input 
signal.

Replace RGB cable.

Check each pin terminal 
of J502.

Normal

Normal

Normal

Defective

Defective

Check output circuit to J502.
1) If +12V is NG, replace main 

PWB.

*  Check inverter PWB unit.
Note: Use caution when checking output 

side because it has a high voltage. 
(1400 Vrms when starting)

Replace LCD module lamp with 
a new one.

Replace inverter PWB 
unit with a new one.

A

A

Screen does not operate normally.

Check RGB cable.

Defective

Replace RGB cable with 
a new one.

Check screen condition by changing display modes.

Reset the microprocessor to check if screen condition changes.
(Press and hold MENU and SELECT buttons while turning on power switch.)

Screen stays in black.

Screen stays in white.

Screen jitters or on-screen 
characters flicker.

Abnormal color

Check the following signals

1) Check if module control signal is output.

2) Check if gate voltage is output normally.

3) Check if Source voltage is output normally.

Yes

No

Yes

No

Yes

No

CLOCK and PHASE 
can be adjusted?

Does abnormal area move on 
screen when BLACK LEVEL or 
CONT is changed after H-POS 
or V-POS is set?

Switch PWB defective

Main PWB defective.

LCD panel defective.