JVC LT-55k800 (A) No standby light with good PSU

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  • pigmeaki
    New Member
    • Mar 2023
    • 7
    • Greece
    #1

    JVC LT-55k800 (A) No standby light with good PSU

    TV:JVC LT-55k800 (A)
    MB: 17MB230 (260319r2)
    PSU: 17IPS72

    Hello! I got a lt-55k800(A) to repair and I am having trouble figuring out if I can save the motherboard or not. Almost 100% the problem is the mb since I have another psu and it does exactly the same. The problem. I was told the tv looked completely dead and indeed there isn't no standby light working. The psu (17ips72) has all the correct voltages in the connector to the mb when it is not connected. Meaning 12v 24v (for sound). There is no stby 5v but it is created by the mb. When I connect it to the main board (17mb230) then suddenly I get weird voltage readings. There is no 5v on the USB, but I get 3.3 at the bios chip and 5 volts at various other spots. Unfortunately someone worked on this board before and they desoldered the audio ic making a bit of a mess in the process. I want to know how to proceed with troubleshooting this.

    Connector Values Without MB
    1- 24V
    2-0V
    ....
    10-12V
    11-12V
    12-12V
    Connector Values With MB
    1- 16.1V
    2-0V
    3-2.5V
    ....
    10-7.8V
    11-7.8V
    12-7.8V

    ​
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