Benq 19" lcd monitor goes blank afer seconds of powering

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  • smd
    Member
    • Jul 2011
    • 12

    #1

    Benq 19" lcd monitor goes blank afer seconds of powering

    I have a Benq monitor model Q9T4 that goes blank after 2-3 seconds after power on. I have tried to look inside for any bulging capacitors, but they all look fine(at least externally). I tried swapping CCFLs (both top and bottom) to no avail. But I noticed that the CCFLs only light up halfway(only one end of both CCFLs lights up with a pinkish glow then goes off).
    Anybody with an idea what is happening here?
  • PlainBill
    Badcaps Legend
    • Feb 2009
    • 7034
    • USA

    #2
    Re: Benq 19" lcd monitor goes blank afer seconds of powering

    Originally posted by smd
    I have a Benq monitor model Q9T4 that goes blank after 2-3 seconds after power on. I have tried to look inside for any bulging capacitors, but they all look fine(at least externally). I tried swapping CCFLs (both top and bottom) to no avail. But I noticed that the CCFLs only light up halfway(only one end of both CCFLs lights up with a pinkish glow then goes off).
    Anybody with an idea what is happening here?
    There are two possibilities. Without pictures it is really difficult to give meaningful advice. First, " swapping CCFLs (both top and bottom) to no avail" is ambiguous. Did you substitute known good CCFLs, or did you simply hook the top CCFLs to the bottom sockets and vice versa?

    1. If this design has a single transformer, the partial lighting could indicate a shorted secondary.

    2. If you substituted known good CCFLs and the design has two or more transformers, I would suspect a low supply voltage to the inverter, possibly due to bad capacitors.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

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