Samsung UE49NU7172U Service Manual page 52

1 1+ 2
7 4+ 8
1. Activate Backlights Test
TV Screen for active backlight LEDs.
9
2. If No BACKLIGHTS
Minus (Control) pins & Plus (Supply) pins voltages on the Panel Connector. (
9
connector only for
• If no pin voltages replace
3. If BACKLIGHTS ON BUT PANEL SECTION(S) OFF
The Supply Drive (
9
• If a Minus (-) pin measures low (near 0 volts), a string(s) of LEDs are likely open.
• Replace Panel
• If a (+) pin measures low voltage and it's minus pin is low but not 0V.
• Check for Defective
BACKLIGHT DIMMING PROBLEMS
• Go to Menu Picture
£
• If no backlight changes observed:
Panel Connector
9
level.
• If minus (-) pin voltages don't change, and PWM_BLU changes, replace SMPS.
• If PWM_BLU doesn't change replace Main/T-Con Board.
Use: MUTE 4 1 9
£ £ £
CNL801 (LED Connector)
1- 3
4- 9
: Disconnect Lead Cable from Main to Power Supply.
safety)
SMPS.
+) pins and (-) pins. All should measure same.
.
SMPS
Expert Settings Backlight
£ £
CNL801 minus (-) pin voltages and PWM_BLU voltages CNM801 while changing backlight
EXIT to test Panel Vertical Backlight Sections in normal operation mode.
£
2+ 4 2-
N.C 10 N.C
and vary level (0 – 50)
4. Troubleshooting
5 3+ 6
11 N.C 12
with fine test probe on left side of
3-
N.C
4-7