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greeneminence

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  1. greeneminence

    Macintosh Performa PSU wrong voltage

    I also noticed something weird - there's a missing resistor (marked R12) in my PSU. Can someone confirm if this is by design?
  2. greeneminence

    Macintosh Performa PSU wrong voltage

    Small update - I replaced all caps in the power supply (except the huge one) but it still doesn’t produce correct voltage. Should I replace the voltage regulators?
  3. greeneminence

    Macintosh Performa PSU wrong voltage

    Thanks for the suggestion. I desoldered all caps in the DC voltage section and here's a complete list of values - maybe someone gonna find it useful: C15 - 330uF / 35V C16 - 82uF / 35V C18 - 2200uF / 10V C19 - 1000uF / 10V C20 - 1000uF / 10V C21 - 82uF / 35V C22 - 82uF / 35V All caps are rated at 105 degrees centigrade. Manufacturer is NIPPON, series LXF, which is discontinued. They recommend LXY capacitors as replacement, as they're low impedance and long life-type caps. Unfortunately, I can't find a supplier of those in my country, so I guess ebay is my go to place for now.
  4. I recently bought a Performa 450 which was in very good condition, no visible leakages, blown-up batteries etc. When I power it on, I can only hear a clicking sound from the speaker. Fan is working correctly. I measured output of the PSU and so far it looks like I'm getting wrong voltage on +12V and +5V lines. It fluctuates around +8.5V and +2.8V respectively. -5V line shows correct voltage though. Do I have faulty voltage regulators or should I recap the PSU? It's one of the Dyna Comp (not TDK). Close-up photos attached.
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