Vizio D65U-D2 Intermittant Back lights

[johns1mj]

Started inspecting a d65u-d2 for losing picture while watching. Using a flash light I was able to determine a backlight issue. It could take 5 minutes or all day. Once it does it you can get it to repeat fairly quickly. Every time you shut off the tv and turn it back on the lights come back on atleast for a minute. Since I knew it was a lighting issue I started testing at the inverter board. All voltages into the inverter board tested the same when the backlight were on or off. Voltages out did vary. With or with out the back lights on the White and Red pairs of wires all tested around 24 volts. With the back lights on the black wires vary between 3 volts and .5 volts. With the backlights off all but one carries 6.8 volts. The 3rd black wire in from the left on the left connector continously varries voltage.

I suspect bad led strips. I believe the led is getting warm and shorting out. Any opinions?

[CapLeaker]

Re: Vizio D65U-D2 Intermittant Back lights

This TV doesn't have an "inverter board" since it is a LED TV. So it has a LED driver board.
I think that one of the LED's in the backlight is failing. So what you can do here is to turn down the backlights in the menu to next to nothing and see if the backlights stay on longer. IF that is the case, you have to tare down the panel and replace the failing LED(s) or the LED strip(s).

[johns1mj]

Re: Vizio D65U-D2 Intermittant Back lights

I unplugged half the led driver board, the white and black side stays on and the red and black side turns off. I turned down the back lights and it has been on for a couple hours now with both plugged in.

[CapLeaker]

Re: Vizio D65U-D2 Intermittant Back lights

I figured... so you have a bad LED somewhere on those backlight strips.

[johns1mj]

Re: Vizio D65U-D2 Intermittant Back lights

Took it apart and found 1 led that was bad. Repaired the strip and it is working fine now.

[CapLeaker]

Re: Vizio D65U-D2 Intermittant Back lights

good to hear you fixed it!

[howardc64]

Re: Vizio D65U-D2 Intermittant Back lights

Have one with backlight only staying on if turned down really low (like 30%) much brighter will cause the backlight to shutdown.

Ran a youtube white screen test and 1 dead row of LED was visible.



This TV has 16 LED strips (8x 3V LED each strip). Have a LED driver board that supply voltage to all 16 strips independently with 2 connectors. Each connector responsible for 8 strips and 1/2 of the screen. Can use a LED tester to confirm bad LED strip and not the driver board at these connectors.



LED driver board will also allow TV to run with 1/2 screen of backlights. Useful for debugging.

Replaced all 16 strips (new strips were slightly brighter and I suppose will last longer than keeping the old strips that are still good)