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Thread: Toshiba T3200SX power supply troubleshooting

  1. #1

    Default Toshiba T3200SX power supply troubleshooting

    I picked up a T3200SX that won't power on. There is no DC output at all from the power supply and a beautiful squeal. I'm still working my way through the circuit but my question is... When the power supply is functioning normal, which is the power good signal? Or does it not have one?

    1 M-12V
    2 M-5V
    3 GND
    4 P+12V
    5 GND
    6 GND
    7 VCC
    8 VCC

  2. #2
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    If it's squealing, I'd check the main line capacitor(s) first, they've probably failed. They're the big cap(s) on the primary side usually rated between 250-450v.

    Not all power supplies had a power good signal.

  3. #3

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    Quote Originally Posted by GiGaBiTe View Post
    Not all power supplies had a power good signal.
    Okay, that's what I was wondering. Maybe the PSU waits until stable to output, or maybe it's just a free for all! Regarding the troubleshooting... The caps look very nice and the ones I've tested check out. I may get back to them later but I've found a bad MOSFET so I'm examining that and any potential collateral damage. Thanks for the input.

  4. #4
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    You'll need to check all capacitors, just because they look nice doesn't mean anything. Capacitors can look physically OK but have any number of fault conditions, such as high ESR, being open or short or leaking out the bottom rubber seal.

    A capacitor tester which can show capacitance and ESR is needed to verify a cap. A capacitor should nominally be within a small margin of its rated value, but electrolytic caps have a +/- 20% tolerance and can be a bit higher. ESR should also be low, if its more than a few ohms for larger capacitors then the cap is bad. There are ESR charts available online.

    MOSFETS don't usually go bad on their own, something else most likely killed it. I'd suspect faulty capacitors, resistors or diodes.

  5. #5

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    Quote Originally Posted by GiGaBiTe View Post
    You'll need to check all capacitors, just because they look nice doesn't mean anything. Capacitors can look physically OK but have any number of fault conditions, such as high ESR, being open or short or leaking out the bottom rubber seal.

    MOSFETS don't usually go bad on their own, something else most likely killed it. I'd suspect faulty capacitors, resistors or diodes.
    Yep, I understand, that's why I said I may get back to checking the other caps and that I am assessing other potential damage. Busy week at work and home though so I had to set it aside for a week, maybe longer. I'll try to report back when I make progress. Thanks.

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