Repair of an LG split AC system indoor unit PCB

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  • ngml
    New Member
    • Aug 2020
    • 4
    • Belgium
    #1

    Repair of an LG split AC system indoor unit PCB

    I am trying to repair an LG split AC indoor unit, which does not start and gives a CH05 error code.
    This indicates an error in the communication between the outdoor and the indoor unit.
    The outdoor unit is fine, so the problem is the indoor PCB.
    The indoor unit is an LG PC09SQ NSJ (3SNM09JA2FA), and the PCB has the following type number: EAX35907219-1.2 (see photo1)
    I changed optocouplers ICO1X & ICO2X and the NPN transistor S9013 which drives optocoupler ICO2X (see photo2), but this did not remedy the fault.

    Does anybody have the schematics of this board, and is willing to share?

    Any other input/advise regarding troubleshooting, is also much appreciated.

    Thanks in advance


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