The iMac G5 Nightmare

Discussion in 'PowerPC Macs' started by macnerd93, Jun 13, 2014.

  1. macnerd93, Jun 13, 2014
    Last edited: Jun 13, 2014

    macnerd93 macrumors 6502a

    macnerd93

    Joined:
    Nov 28, 2009
    Location:
    United Kingdom
    #1
    Hello all,

    So Last week I won the bid on a mint condition looking iMac G5 17'' 1.6Ghz for £45. The machine on the ebay listing was listed as excellent condition, trusty and in working order, but with no operating system installed, no issue for me.

    The iMac arrived yesterday in original box and first impressions were "This is like brand new". I installed Tiger, but at first the install failed for some reason. Then after another attempt it installed okayish. The fans sounding like a hairdryer through the whole install process. Upon the restart the iMacs power suddenly failed and it cut off mid-starup chime and no matter how many times I tried it wouldn't successfully power into life, just cutting off after about 3-5 seconds.

    I took the back off and found this horror on the logic board
    [​IMG]
    As you can see the caps are leaking quite badly, which I assume is accounting for the iMacs erratic behaviour. On the 1 out of every 10 attempts I managed to get it to successfully boot to the desktop the fan sounds like a hairdryer constantly and the CPU even just on the desktop with no applications open at all is running extremely hot. Its highest has been 88.6C before it cuts off and goes into sleep mode.
    [​IMG]

    I am really annoyed that I was told the machine was in good order, but in reality it is anything but. In the end I've decided to swap out the logic board finding one in America from a 1.8Ghz 17'' G5 for about £38 including shipping. I would say the only reason why I am keeping it is because of the outstanding condition externally. If it had been in poor condition and also not working I think I would have requested a refund from eBay.

    A photo when I actually managed to get it to boot up [​IMG]
     
  2. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #2
    I actually was given an iMac G5 same model for the cost of shipping from a very kind SkippyThorson. It is in the mail now. I am going to do a guide in the future on rebuilding the Logic Boards and PSUs.

    Since it is in such mint shape, I doubt the previous owner opened it. Capacitor issues are tricky and the could have honestly not even known.
     
  3. Hrududu macrumors 68020

    Hrududu

    Joined:
    Jul 25, 2008
    Location:
    Central US
    #3
    The good news is the iMac G5 is probably one of the easiest Mac's to recap the logic board. Even if you're not great at soldering, it really isn't a difficult task. Over the years I did many of them, and I think I only had one that needed redone because I didn't get a good connection. Just don't throw that old board in the trash!
     
  4. macnerd93 thread starter macrumors 6502a

    macnerd93

    Joined:
    Nov 28, 2009
    Location:
    United Kingdom
    #4
    I have recapped stuff before and am in the process of starting to recap a 1958 Ferranti Valve Radio, but everyone tells me its hard to separate the solder in the G5 from the logic board and often can cause damage making the board unusable. Thats what persuaded me to buy the 1.8Ghz logic board coming all the way from Ohio to the Uk.

    I'll likely sell the 1.6 logic board as spares and repairs.
     
  5. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #5
    With a powerful enough soldering iron it works well. I recommend not using a desoldering wick though.
     
  6. macnerd93 thread starter macrumors 6502a

    macnerd93

    Joined:
    Nov 28, 2009
    Location:
    United Kingdom
    #6
    just a little update since last night. I have now discovered if I unplug the machine and leave it for an hour or two it works fine during boot up, but still drops into sleep mode after about 5-6 min just doing nothing.
     
  7. archtopshop macrumors regular

    Joined:
    Dec 13, 2011
    #7
    You should check the 4 diagnostic LED's on the logicboard. I have put the Apple Repair Manual for your computer in my dropbox. It explains how to interpret the LED's, and everything else you could ever want to know about your computer. Here is the link (54.1MB):

    https://db.tt/pxx7plo6

    The sleep mode issue sounds like overheating. The 4th LED being on would confirm. What's causing it to overheat could be many things, though. The bad capacitors on the logicboard, bad capacitors in the power supply (which you should remove and , at least visually check), or dried up thermal paste.

    Anyway, the repair manual is a good place to start.\\
     
  8. macnerd93 thread starter macrumors 6502a

    macnerd93

    Joined:
    Nov 28, 2009
    Location:
    United Kingdom
    #8
    Yeah the 4th LED is illuminated, thanks for this. It has a Delta electronic's PSU. I have just bought the better AC Bel replacement which apparently had no issues in regards to capacitors leaking, unlike the poor quality Delta electronics version
     
  9. archtopshop macrumors regular

    Joined:
    Dec 13, 2011
    #9
    You're welcome. Glad I could help. The iMac G5's are very nice computers--nice displays, especially on the 20"--and pretty fast. I've recapped four of them over the past few months. I use two of them myself and gave the others to friends.

    Once you get yours running, I'm sure you will enjoy it.
     

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