Need a power supply with 25V

Discussion in 'Macintosh Computers' started by rufus1, Dec 6, 2005.

  1. rufus1 macrumors newbie

    Dec 6, 2005

    I need a replacement power supply for my Mac G4 Quicksilver (part 614-0157) but all the prices I've seen are outrageous. I am in the process of converting an ATX power supply for use in the Mac but I discovered that I do not have a +25V line. Is there an adapter or alternative power supply that will give me 25V?

    These are the specifications on the Mac PSU:

    +250VS 4.5A
    +250VL 2.5A

    I appreciate any help that could help me bring my Mac back to life. It is currently a stylish paperweight.
  2. jtown macrumors 6502

    Jul 3, 2003
    Just go on ebay and look for someone parting out a quicksilver. You might have to give it a couple weeks but you should be able to find a cheap power supply.
  3. rufus1 thread starter macrumors newbie

    Dec 6, 2005
    I saw a QS Power supply on ebay, but they were selling it at a ripoff price.

    Are there any other Mac power supplies that use +25V?
  4. RGunner macrumors 6502a


    Jul 3, 2002
    Midnight Sun
    25v Psu

    there are several threads on this at forums.

    only the MDD PSU from Apple has the right Voltages, but the mods needed to make it fit the case do not justify the work involved, and then you have a botched up QS (and the risk of miswiring).

    There is a reason the Ebay PSU's are fetching $100+, they cannot be duplicated easily. Best bet would be a Digikey or Radio Shack AC-DC Transformer with the +25V output.
  5. rufus1 thread starter macrumors newbie

    Dec 6, 2005
    Okay, here is an update:

    I spliced wires to match the mac motherboard connector, and the addition of an 24V adaptor to power the 25V line for the Apple ADC video. see an image of the FrankenPSU here

    I flipped on the power strip switch, powering the PS (pin 14 shorted) and the ac adaptor. The fan on the CPU spins, and a motherboard light powers on. The hard disk, however, will not start up with the motherboard connected. Also there is no video output.

    I know my voltages for each connector pin are correct, but I have not checked current or paid any attention to rails. I don't know which Mac pin needs an independent +3.3V, for example, and which ATX wires provides it.

    I wish I could post on xlr8yourmac, but the forums are closed to new users for some reason.
  6. rufus1 thread starter macrumors newbie

    Dec 6, 2005
  7. rufus1 thread starter macrumors newbie

    Dec 6, 2005

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