Troubleshooting Backlights
Additional Option : 55 inches
Ref. Chassis Ground
(
Voltages Vary with Panel Size
)
33Vdc
84Vdc
Remove
1.
CN9003
(
Main
↔
SMPS
) to activate backlights.
Check each separate backlight supply at the 8 circled Diodes for approx.
2.
84Vdc
by connecting the multi meter to CH1 through CH8 Cathode Stripped side of Diodes. (Ref. Chassis Ground)
If any are missing or low, remove the panel connectors and re-test. If it stays low the SMPS Board is defective. If it goes
3.
up to same reading as the other CH supply voltages with the connector removed, the Panel is defective (a string of
LEDs are shorted).
Check the eight Diodes anode side. They should measure approximately
4.
33Vdc
.
If any read 0V and corresponding CH was ok (
84Vdc
). The Panel is defective (open string of LEDs).
4-7
4. Troubleshooting
