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Hard Drive Brushless DC Motor Controller

Discussion in 'Misc Electronics' started by Andrew, Oct 26, 2004.

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  1. Andrew

    Andrew Guest

    I have an old Western Digital Caviar 22500 hard drive that failed. I
    hate to see good electronics go to waste. I salvage almost anything.

    I am trying to get the hard drive spindle brushless DC motor to run.
    What better controller than the one that came with the hard drive? I
    will save me the trouble of building one - these circuits are
    complicated. When I tried it, the motor powers off after about one

    It seems that the hard drive does its initial diagnostics and realizes
    that there is an error (no read/write heads), and powers off. I cannot
    figure out how to stop the motor controller from shutting down.

    The motor controller IC is UCC3285QP. I cannot find specs on this part
    or similar ones with the same pinout configuration. I'm at a dead end.

    Does anyone with knowledge on hard drive circuitry have any clues on
    how to prevent the motor controller from shutting down. I don't want
    to have a motor that's useless or expensive to operate.
  2. You can buy a used one from Ebay for less than 10 dollars. You could either
    swap parts or use it as it is. :)
  3. Andrew

    Andrew Guest

    I would still rather get the hard drive motor controller on the hard
    drive circuit board to work without shutting down. I would only pay
    extra cash if I had an immediate use for the motor and wanted it
    working right away.

    So far the best I am able to get is applying a low voltage to pin 36
    of the UCC3285QP. It stops the drive from powering down but now the
    motor speed becomes unsteady and more noisy.

    It seems I just need to figure out how to prevent the UCC3285QP from
    knowing that it has to stop the motor, or get it to run independently
    from the rest of the hard drive circuitry. But lacking any data sheet
    or at least a pinout configuration, I am clueless.
  4. Andrew

    Andrew Guest

    I figured out a way!

    I was focusing only on the motor controller IC. I then shifted focus
    to other parts of the circuit. I thought that if I could trick the
    circuit into thinking that there's a read/write head, then maybe it
    would not shut down.

    I made a connection from one of the pins leading ot the read heads and
    connected it to a digital line that gives a lot of alternating ones
    and zeros.

    It worked. The motor starts up and remains running smoothly. So I
    saved myself buying or building a brushless DC motor controller.
  5. Guest

    I figured out a way!
    its really nice to hear.can u explain me in detail.iam trying to fix it
    since 1 month.imean trying to run HDD motor with out stopping.but no
    my HDD is samsung 20GB model.if u any other circuit which can drive HDD
    spindle motor
    ple help me
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