Samsung QN49Q6FNAF Service Manual page 64

4. Troubleshooting
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
• If minus (-) pin voltages don't change, and ANA-DIM changes, replace SMPS.
• If ANA-DIM doesn't change replace Main/T-Con
Use: MUTE £ 4 £ 1 £ 9 £
4-12
: Disconnect Lead Cable from Main to Power Supply.
safety)
SMPS.
+) pins and (-) pins. All should measure same.
SMPS
Expert Settings £ Backlight and vary level (0 – 50)
minus (-) pin voltages and ANA-DIM voltages CNL801 while changing backlight level.
EXIT to test Panel Vertical Backlight Sections in normal operation mode.
with fine test probe on left side of
Board.