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G5 Power supply PA-6601-1 fan problem

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    G5 Power supply PA-6601-1 fan problem

    Hi,
    this is my first posting of a problem on this forum and my first experience with an Apple G5. The PC - if I can call it a PC - fires up fine and all is well - but - none of the fans come on, so I am assuming the problem is in the power supply. The display also won't come on, but I suspect again that it also needs 12v DC (the same as the fans) to drive the display. I connected a separate display with it's own power supply which worked fine.

    The unit finally shuts down when it gets to hot as the fans are not running. It fires back up again when you have allowed it to cool down so I would say it's "only" a 12dc supply problem (I hope).

    After finding a good website on how to remove the power supply, I've finally managed to get the power supply out - what a job that was - but I don't know which pins to short out to simulate switching on the power and I don't have any information on the pin out on each of the plugs. I have had a look around on the web and found information about G5 power supplies but they are not the same power supply as the one I have which is the Liteon PA-6601 which seems to cost about £160 UK pound for a replacement.

    I was given the complete unit, display and keyboard as the previous owner had been told that the power supply was faulty and needed replacing. He felt it was not cost effective to have it repaired. As this is my first look at an Apple Mac I thought it "might" be worth trying to repair the faulty power supply.

    Another option would be to locate the output for the 12 DC line, disconnect it from the power supply and then connect a normal PC power supply to supply the 12 DC line to the fans and display.

    Any thought on how to address the 12 dc supply problem - and - is it worth trying to fix this thing?? I'm always up for a challenge but I wander if this one is worth the effort.

    Thanks in advance for any feedback, comments or advice,

    Siggi

    #2
    Re: G5 Power supply PA-6601-1 fan problem

    Can you open the power supply case and make some snapshots of the inside? It can't hurt.

    Maybe it can be fixed by replacing some cheap parts... it looks like the PSU has a 25v output - maybe that's used for the monitor. Fans are usually connected to the 12v line.

    Comment


      #3
      Re: G5 Power supply PA-6601-1 fan problem

      Hi and thanks for replying to my post..

      I've attached the photo of the power supply
      Attached Files

      Comment


        #4
        Re: G5 Power supply PA-6601-1 fan problem

        I am not familiar with Apples in particular but hard drives and CPU VRMs also use 12V.

        Comment


          #5
          Re: G5 Power supply PA-6601-1 fan problem

          There are a few threads about these supplies. Success has been limited. Results are less than encouraging. Best bet is to track back the 12v (yellow) line and see where it is failing. Take a look around the TOPSwitch and see if there are any -obvious- blown components.

          What voltages are you getting? Minimum of 5vsb and 25vsb for operation, then the usual 3.3, 5, 12, and -12.
          veritas odium parit

          Comment


            #6
            Re: G5 Power supply PA-6601-1 fan problem

            Hi and thanks for the replies. Do you know the pin out for the three connectors coming from the power supply?
            There is an 8 pin one, a 24 pin one, but only 22 pins are used and a 16 pin one. Also, do you know which two need to be shorted to switch the power supply on?

            As the PC actually works (bar the fans and the supply to the screen) I’m assuming the problem relates to the 12v DC line.

            Comment


              #7
              Re: G5 Power supply PA-6601-1 fan problem

              Green and black. Look on the board itself, they're all marked.
              veritas odium parit

              Comment


                #8
                Re: G5 Power supply PA-6601-1 fan problem

                Hi, that was quick.
                Thanks, I've cleaned away some of the white glue / paint and I can now see the marking on the board.. I'll start checking the various supplies and post the results.

                Comment


                  #9
                  Re: G5 Power supply PA-6601-1 fan problem

                  Ok.. some good news and some bad news.

                  I checked all the connectors and got the following

                  Yellow = 12.2V
                  Orange = 3.3V
                  White = 25V
                  Purple = 5V
                  Blue = 12V
                  Red = 5V

                  So it all looks as if it was working. I reinstalled the power supply and connected everything back up and – hey presto all the fans are back on again..
                  I guess I must have moved some of the components around on the power board which seems to have fixed the problem.

                  Thanks for everyones help
                  Siggi
                  Last edited by ingasos; 09-13-2011, 05:48 AM.

                  Comment


                    #10
                    Re: G5 Power supply PA-6601-1 fan problem

                    Sounds more like a bad connector than a loose component.
                    veritas odium parit

                    Comment

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