Backlight Test :
CNL802
1
1/2+
2
1-
3
2-
4
3/4+
5
3-
6
4-
7
5/6+
8
5-
9
6-
10
7-
11
8-
12
7/8+
CNM803
B_GND
1
2
B_GND
N.C
3
4
N.C
B350V
5
6
B350V
N.C
7
8
N.C
GND
9 10
GND
VAMP(B13V) 11 12
B13V
VAMP(B13V) 13 14
B13V
VAMP(B13V) 15 16
B13V
A13V(N.C)
17 18
GND
PS_ON(N.C) 19 20
GND
ANA_DIM
21 22
N.C
GND(Signal) 23 24 BLU_ON/PWM2
N.C
25 26 BLU_ON/PWM1
CH1 /
PWM1
CH2 /
PWM2
CH4 /
PWM2
CH3 /
PWM1
Simplified: SMPS/PANEL BACKLIGHT TEST: (Series Wired SMPS Panel Connections)
1. Activate Backlights Test
: Disconnect Lead Cable from Main to Power Supply.
CN201
9
Check TV Screen for active backlight LEDs.
2.
If NO BACKLIGHTS (Series wired SMPS Panel Connections)
9
Plus (+) & Minus (-) pin voltages on the Panel Connector.
→
If no pin voltages replace SMPS.
→
If voltages exist but no backlight
9
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 voltage was low and remains low the SMPS is defective.
→
If the voltage was low and goes high a string of panel LEDs are shorted replace the Panel.
BACKLIGHT DIMMING PROBLEMS:
1.
Go to
Menu
£
Picture
£
Backlight
and vary level (0 –20)
2.
If no backlight changes are observed:
9
Panel Connector pin voltages and
BLU_PWM
voltages
CNM803
while changing backlight level.
→
If Panel voltages don’t change, and BLU_PWM changes, replace SMPS.
→
If BLU_PWM doesn’t change replace Main/T-Con Board.
4-17
4. Troubleshooting