LG55UB850V no picture or audio, just flashing LED's help please?

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  • IAmOrion
    Member
    • Jan 2024
    • 10
    • United Kingdom

    #1

    LG55UB850V no picture or audio, just flashing LED's help please?

    Hi members, I came across this forum when searching a fault on my LG 55UB850V TV.
    Rather than hi-jack another members post/thread I thought I should start my own even though it's an almost identical issue.

    The thread I refer to can be found here:
    https://www.badcaps.net/forum/troubl...-s-help-please

    My boards are the same, and my issue it the same. I have NO Picture and NO Sound. Nothing. When first turning on the TV at the mains sockets, the RED LED turns on and stays on solid in standby mode.
    When I press the power button on the remote (or trigger it via the joystick thing underside of LG logo and red led), the red led flashes 3 times, then turns off. Then nothing happens, ever.

    Here's photos of my boards:

    Click image for larger version  Name:	IMG_4514.jpg Views:	0 Size:	3.04 MB ID:	3206351


    Click image for larger version  Name:	IMG_4515.jpg Views:	0 Size:	3.25 MB ID:	3206349

    Click image for larger version  Name:	IMG_4516.jpg Views:	0 Size:	3.47 MB ID:	3206350

    With the back removed, LED LD1900 on the main logic board lights up briefly for around 1 seconds, then turns off.
    LED LD2300 remains solid red
    After about 1 minute or so, LED LD701 on the power board flashes 5 times in a row, then about a 5 seconds pause, then repeats the 5 second flash. This repeats itself indefinitely.

    Fuse F1 on the Display board (aka T-CON as I've come to learn) only give me around 0.835v

    J71 reads 11.8v, J75 reads 23.8v

    I don't have a service remote, I used my Flipper Zero to try the IN_STOP commands using this file: https://github.com/Lucaslhm/Flipper-...828_Service.ir

    Whilst the Power and P-ONLY commands visibly work, IN_STOP doesn't appear to do anything. I have ordered what I think is the correct service remote (just in case flipper isn't sending command correctly or it's wrong)

    Click image for larger version  Name:	Screenshot 2024-01-29 at 00.24.50.png Views:	0 Size:	660.2 KB ID:	3206354
    I'm hoping this is the correct service remote!

    I've tried holding the tactile switches for 10 seconds whilst turning on etc but to no avail either.

    My Optical Audio socket DOES have a RED LED lit up on it.

    I have tried all the tests with and without the WiFi/BLE module attached again to no avail.

    Now, the only difference so far compared to that existing thread, is that PIN 18 of my 26 PIN connector is 0v. All other recommended to test pins are correct (8, 12, 14, 20, 22)

    I also unplugged the to connection at bottom of display board (I presume it's panel connection if I read correctly?) but the Fuse F1 was still at 0.835v.

    I've unplugged, re-plugged, cleaned, re-seated, all connections. I've removed each board and cleaned behind them etc.

    Click image for larger version  Name:	IMG_4513.jpg Views:	0 Size:	7.48 MB ID:	3206355


    I have not yet tested the 5v USB output, I ran out of time today. Next day I will have free time again will be Tuesday 30th so hoping there may be some replies to give me things to test and check / try.

    Many thanks in advance
    Attached Files
    Last edited by IAmOrion; 01-28-2024, 06:54 PM.

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