imac g5 power supply problem

Discussion in 'PowerPC Macs' started by trickassfoo, Aug 29, 2012.

  1. macrumors newbie

    Joined:
    Aug 29, 2012
    #1
    Well I had my imac 17 g5 sent out to me and when I tried to turn it on, nothing happened. I took the back cover off and led 1 lit, while led 2 did not. I checked the capacitors on the logic board and they all seem fine, although when I opened the power supply I found one capacitor bulged at the top and a red pasty material had seeped out. My question is can I replace that one capacitor, or have the power supply repaired rather than invest any money into this aging computer? The replacement power supply units are too expensive for me to justify putting into a free computer.
     
  2. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #2
    It wouldn't hurt to try to replace that one capacitor.
     
  3. thread starter macrumors newbie

    Joined:
    Aug 29, 2012
    #3
    I've never repaired a board like this, wondering what type capacitor it is and where i could find one of these?
     
  4. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #4
    If you look on the capacitor, you'll see two important numbers. One is the voltage, it'll appear like this "12v". The other is the farad capacity, it'll appear like this "220 μF". The ones that look like cylinders are called electrolyte capacitors because of their chemical makeup. They can be found at places like Fry's or Radio Shake. But they'll be more expensive and they might not have the ones you need. A good online retailer is Digikey.

    A few things to note, there are a few different thermal designs. One is 105C and I think the other is 85C. I suggest getting the 105C ones due to the heat inside of the G5 iMacs. The other thing to remember is that capacitors are polar, that is one leg is positive and the other is negative. Make note on the old capacitor where the stripe is on the casing. Make sure the replacement capacitor has the stripe on the same side. Otherwise, it may not work.
     
  5. macrumors 68000

    Nameci

    Joined:
    Oct 29, 2010
    Location:
    The Philippines...
    #5
    Otherwise it would explode if you reverse yhe polarity.
     
  6. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #6
    Oh yes. Big bang, cool toxic smells, and pretty blue lights.
     
  7. macrumors 6502a

    Macman756

    Joined:
    Sep 24, 2008
    Location:
    Atlanta, GA
    #7
    Another note is the lead-free board, the solder requires a lot of heat to melt. Cheap solder irons will not melt the board. $100+ iron, roughly 900 degrees F.
     
  8. macrumors 68000

    Nameci

    Joined:
    Oct 29, 2010
    Location:
    The Philippines...
    #8
    Yes it is, you are correct. I have worked as a Test Technician previously for a power supply company, which manufactured power supplies for big companies such as HP, Nortel, IBM to name a few.

    If the assembly operators mistakenly mounted it reversed and the first station is power up, BAM! awesome smell... all personnel gets out of the assembly area.

    Anyway, to the OP, the best way to always remember is to take a photo of it before you desolder it out of the board.
     

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