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Harddisk problem

Discussion in 'Electronic Repair' started by Kevin Lam, Dec 14, 2003.

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  1. Kevin Lam

    Kevin Lam Guest

    Hi experts,

    A week ago when I was browsing the net, the computer suddenly shut
    down, as if there is a power cut, it failed to power on.

    My experience told me that it seems like a power surge causes either
    the motherboard or power supply gone...

    I changed the power supply but it still refuses to boot up. Then i
    discovered that if i unplug the harddisk, it works perfectly.

    What's the most likely cause of this problem? and how could i recover
    the harddisk information??


  2. Guest

    By "Unplug," I assume you mean the power plug??? If the power refuses
    to come up with the HD power leads attached, then the HD is drawing too
    much current. Normally a new logic board for your HD would solve your
    problem and allow you to retrieve the data.

    If on the other hand you find the problem is the IDE cable and not the
    power cable, it is probably also the logic board, but there is a VERY
    slight chance the IDE cable is defective. Try a different IDE cable
    before condemning the logic board of the HD.
  3. w_tom

    w_tom Guest

    It fails to power up or fails to boot? The first tool a
    computer repairman would use is the 3.5 digit multimeter.
    Which critical voltage is not obtaining spec? Then that
    missing voltage would cause the others to shutdown. Which
    voltage is an important fact.

    Apparently disk drive is shorting out one of the voltages.
    However that short typically would cause a visually noticeable

    Again, this assumes power failing - which was not directly
    stated in the original post. Computer could simply fail even
    though voltages are OK. Or disk drive could be loading power
    supply to the hairy edge now causing failure. We don't have
    definitive facts about power.

    How to recover data? Well one system recently stopped
    booting. Traced failure to a drive transistor on disk drive.
    Eventually got that circuit repaired. All data, except one
    file, recovered. Notice that first I identified failure. Only
    then tried to fix it.

    Experience tempered by how things work says surges are
    rarely reason for failure. Most who blame surges are simply
    speculating due to retail shelve propaganda; not because
    electronic analysis is performed. Take this disk drive
    transistor failure as example. If a surge causes this damage,
    then many other things would have also been damaged. Failures
    are more often attributed to manufacturing defects.

    Drive data may be recoverable as I recently demonstrated.
    From information posted, nothing can be definitively
    identified as reason for failure. It is why analysis starts
    with a 3.5 digit multimeter - and other important details.
    Same detailed analysis demonstrates that most 'surge' damage
    is based only in speculation. Surges are that rare and would
    have damaged far more than one drive.
  4. Andre

    Andre Guest

    I had a power supply fail like that, the vendor didn't want to know
    but did tell me that my machine was likely to be OK as the modern PSUs
    fairly well insulate the mainboard against power spikes if they aren't
    too big.

    Chances are that the spike has shorted a tantalum capacitor (little
    black or yellow surface mount thing) on the drive's controller board,
    this can be a single shot event with those. Good news is if you remove
    the "bad" capacitor and the drive starts working, it should be
    recoverable though don't trust it with unbacked-up data :)

    I know of cases where replacing this one part has gotten the drive
    working again and it has been fine for years afterwards.

    #include "Disclaimer.h"
    #include "YMMV.h"

    Then i
  5. Jef

    Jef Guest

    If your at a business with a lot of those computers go take the circuit
    board off a similar hard drive. It works most of the time in this
    situation. -jeff
  6. Hawkeye

    Hawkeye Guest

    Don't eliminate the power supply just yet. It could be that it is
    borderline and plugging in the HD puts it over the edge.

    Try the drive and the PS in a different computer if possible, but not
    at the same time...
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