Samsung UN55MU8000 - Backlight But No Picture Problem

[KYBOSH]

Re: Samsung UN55MU8000 - Backlight But No Picture Problem

remove the shorted capacitor, if the short is gone on the board, it should just need a replacement and then be back to working state.

Thank you very much @Biruslapio.
Would you have any advice on what size cap this should replace it with?

[Biruslapio]

Re: Samsung UN55MU8000 - Backlight But No Picture Problem

remove the shorted capacitor, if the short is gone on the board, it should just need a replacement and then be back to working state.

[KYBOSH]

Hello all

I pick this up free as a repair project for the holidays.
The original symptom was power cycling after 3-4 seconds with a single red light flash.

To remedy this I went through and unplugged each component 1x1 and discovered that when the FFC cables were disconnected the backlights stayed on and the TV did not reboot.

I tried remove one or the other to see which side of the display was causing the issue (expecting to see half a picture to show) but didn't see anything. But the boot loop only appears when the top FFC cable (right side of the display) was connected. I tracked down the offending/shorted tracks to the first 2 traces. I taped those off and reconnected everything. No reboots but no picture.

This unit comes with a One Connect box. With these models when the One Connect box is not connected we get a warning image upon telling you to connect the box. There was no warning image... When I connected the One Connect box I still didn't see anything but on a whim I started pressing some buttons on the remote control (specifically the menu button) and I started hearing input sounds as I scrolled thru the icons.

This told me that the one connect box was functional.
It also told me that the mainboard was at least semi-functional.

I read a few threads and watched a few videos about panel display issues, COF, ect. Unfortunately similar repairs to the MU series has not been document on these forums.

I went through every component on the LCD Panel PCB and found only one shorted capacitor (highlighted in RED in the pics). No other SMD was shorted. I also when through and tested for voltages across the panel board while the TV powered up and only saw voltages of 3.3v in a few places and ~1.8v in others.

I cannot find any place on these LCD Panel PCB marked VGH of VGL. I cannot find any place on the panel board OR the mainboard where 25v is present or supposed to be supplied.

This is my first go at LCD Panel board repair. I want to learn about it but this TV seems different than the ones I am seeing on YouTube. I speaking directly to the lack of a marked VGH test point.

I wanted to consult you good ppl of BadCaps before I did anything other than probing.

Obviously I'd want to removed the bad cap.
Should I replace it or leave it open?
Would that alone be the cause of a No Picture issue?

Below are some pics of what I am dealing with and seeing.

Your input is greatly appreciated!