1 P702UI-B3 LEDs Not All Working Correctly
We are trying to troubleshoot why the LEDs are not functioning on a P702UI-B3 TV. Originally the main board on the TV was faulty and the TV would not power on at all. This was replaced and the TV would boot but half the screen was very dim. We replaced the LED driver board which did not fix the issue. We then disassembled the TV down to the LED strips to test those directly.
The LED strips are getting voltage, and when a strip that does not light up or illuminates dimly is plugged into a terminal that functions, that strip begins to function. When a good strip is plugged into a bad terminal, it does not function. This leads us to believe the strips themselves are good.
When the TV is left on for some time, the strips do eventually illuminate dimly, although not nearly bright enough in comparison to how they should illuminate.
In testing voltages, the LED driver board is getting the correct voltage readings from the power supply. The working LEDs are getting around 10VDC and the non-functioning LEDs are getting 13VDC.
Since replacing the LED board did not solve this, is it possible that the power supply board is bad? Or, should I try a third LED driver board, even though both boards present the exact same symptoms? Any help troubleshooting this would be greatly appreciated.
Update (10/18/2020)
Attached are pictures of all boards in the TV.
Is dit een goede vraag?
@atrotter01 "The working LEDs are getting around 10VDC and the non-functioning LEDs are getting 13VDC." where did you measure those voltages?
door oldturkey03
@oldturkey03 On the led strip power terminals directly and the cables from the led board to the led strips.
door Stuart Trotter
That voltage seems to be way off. What voltages do you get on your power board and your LED driver board?
door oldturkey03
Each 24V pin going between the LED driver board and the power board reads 24V which matches the spec printed on the power board. I can check the voltages on the LED strips again tomorrow just to ensure we didn't misread them. What should the voltages typically be?
door Stuart Trotter