Samsung UN KU650DF Series Service Manual page 73

4. Troubleshooting
BACKLIGHTS
„
2+
1
2 NC
3 NC
2-
4
5 NC
6 NC
7 NC
8 NC
1 Fail Count
2 ANA-DIM
3 A13V
4 OD_ON/OFF
A13V
5
BLU_PWM
6
1. Activate Backlights Test
Disconnect Lead Cable from Main Board to Power Supply. (CN202)
-
√ TV Screen for active backlight LEDs.
2. If NO BACKLIGHTS
√ Plus (+) & Minus (-) pin voltages on the Panel Connector.
If no pin voltages replace SMPS.
-
If voltages exist but no backlight:
-
√ The highest pin voltage (BL Drive Supply )
Remove Panel connector and measure again to compare.
-
If the voltage was high and stays the same high reading a string of Panel LEDs are open. Replace the Panel.
-
If the v oltage was low and remains low the
-
If the voltage was low and goes high a string of panel LEDs are shorted replace the
-
For BACKLIGHT DIMMING PROBLEMS:
• Go to Menu → Picture → Backlight and vary level (0 – 20)
• If no backlight changes observed:
√ Panel Connector pin voltages and BLU_PWM voltages (CNM803) while changing backlight level.
• If Panel voltages don't change, and BLU_PWM changes, replace
• If BLU_PWM doesn't change replace
4-4
CNL802
1+
9
10 NC
11 NC
1-
12
13 NC
14 NC
15 IF2
16 IF1
CNM803
7 A13V
8 POWER_ON/OFF
9 A13V
10 GND
11 GND
12 GND
:
Main/T-Con Board.
SMPS is defective.
SMPS.
CN202
CNM803
Panel.
CNL802