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    Backlight or inverter?

    Discussion in 'Hardware Components and Aftermarket Upgrades' started by Hokiedad, Jan 28, 2008.

  1. Hokiedad

    Hokiedad Notebook Enthusiast

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    I just inherited a Sager NP8886 from my deceased sister. The LCD panel flickers and sometimes will turn off, then back on after a few minutes. How do you diagnose an inverter versus a backlight failure? An external monitor works flawlessly.

    Otherwise, the system runs fine, and fortunately, the repair looks real easy. Just don't want to buy expensive parts I don't need.
     
    Hokiedad, Jan 28, 2008
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  2. jimbob83

    jimbob83 Notebook Evangelist

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    Before replacing anything, check for a loose cable and try fiddling with the lid switch.

    The inverter is much easier to replace than the backlight and is not that expensive (I bought a replacement for my sister's HP a few months ago, cost $19.99). I would try changing the inverter first, then change the backlight if that didn't fix it.

    If you know your way around electrical equipment and have a multimeter, you could measure the output from the inverter to see if its live. I don't know what the voltage should be, but it will be AC.
     
    jimbob83, Jan 28, 2008
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  3. HPpavilion

    HPpavilion Notebook Consultant

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    On a laptop I was working on before, the inverter had two connectors. One for power and control, another for backlight output. The backlight one has two wires and came out relatively easy, but I can't get the other connector off and my gut feel was I was going to rip one of the tiny wires off the connector if I kept trying. Anyone else run into this?

    Backlight runs at hundreds of volts at tens of kilohertz. ordinary DMMs are not designed to handle it and will draw too much current due to capacitance of the DMM input causing the inverter to shut off and/or damage the meter.

    It is basically a miniature version of fluorescent lighting ballast.
     
    HPpavilion, Jan 28, 2008
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  4. Hokiedad

    Hokiedad Notebook Enthusiast

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    I'm fairly sure it's not a loose connector. I'm going to open it up tonight. The service manual makes it look easy, with just two connectors and a couple screws. I did find a place that says they can repair inverters, so I sent them an e-mail.

    Thanks for your input.
     
    Hokiedad, Jan 29, 2008
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  5. Hokiedad

    Hokiedad Notebook Enthusiast

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    Update: Sager shipped a replacement inverter and the panel is working perfectly. 20-minute job.
     
    Hokiedad, Feb 8, 2008
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  6. ivar

    ivar Notebook Deity

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    imho, it can be either or both with an equal chance. the backlight itself is not expensive (10$), cheaper that inverter, and easier to get because it is not model specific.

    There are goof online instructions as to how to replace inveter and backlight.
    If you're not afraid to open the notebook and the display, you're probaby ready to do the replacement yourself after reading the instructons and following them carefully.

    Good luck!
     
    ivar, Feb 8, 2008
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  7. NGH

    NGH Notebook Evangelist

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    Is it possible to add an additional backlight to HP 9030us
     
    NGH, Feb 26, 2008
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