Have I killed it?

Discussion in 'PowerPC Macs' started by stu232, Mar 28, 2015.

  1. stu232 macrumors newbie

    Joined:
    Mar 28, 2015
    #1
    A few years ago my beloved 2004 iMac G5 started turning itself off so I decided to put it in storage and upgrade. :cool:

    Yesterday I came across it in the attic and decided to fire her up again. :)

    The machine was starting up fine but it would switch itself off for no reason, I took the cover off and I saw that about 8 of the caps were badly swollen. I went online and ordered 20 x 1800uF 6.3v and 5 x 1000uF 16v capacitors.

    I decided to press down on the swollen capacitors (bad idea) and I managed to flatten them again.....(very bad idea).....so now when I power her up I get 3 beeps and the front light flashes 3 times then repeats.

    AFAIK this is a problem with the RAM, but I know the RAM is fine as it was working up until I pressed on the swollen capacitors. I also tested the RAM in an old PC and it works fine.

    The motherboard LED's are displaying 1 and 2. The third one flickers when the power is first supplied then it goes off.

    So I'm getting no chimes, no display, 3 beeps, 3 flashes on the power LED and only 2 of the onboard diagnostic lights are showing.

    Someone please tell me that all I've done is destroyed the Caps and replacing them will bring her back to life!

    :eek:
     
  2. ctmpkmlec4 macrumors 6502

    ctmpkmlec4

    Joined:
    Jul 4, 2014
    Location:
    Lyons, KS
    #2
    If you're good at soldering, you can replace the failed capacitors. However, it would probably just be easier to find a replacement logic board.
     
  3. stu232 thread starter macrumors newbie

    Joined:
    Mar 28, 2015
    #3
    Yeah I can solder, I've already bought the replacement caps.
    I'm just waiting on them being delivered.

    I just hope I haven't done some serious damage when I pressed down on the bad caps.
     
  4. ctmpkmlec4, Mar 28, 2015
    Last edited: Mar 31, 2015

    ctmpkmlec4 macrumors 6502

    ctmpkmlec4

    Joined:
    Jul 4, 2014
    Location:
    Lyons, KS
    #4
    I doubt you've done any more damage than what the bulging caps could have caused. These logic boards are tough to repair. My only attempt to recap an iMac logic board was unsuccessful. I'm sure you have better soldering skills than I do, so don't let that discourage you. Best of luck! Let us know the outcome.
     
  5. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #5
    Unless the board flexed a lot when you pressed down, you likely did no damage at all. Pressing down either finally totally killed the cap or broke the solder joint. Either way, it likely will be resolved when you install the new capacitors.
     
  6. stu232 thread starter macrumors newbie

    Joined:
    Mar 28, 2015
    #6
    Thanks for the replies guys, now I just need to wait for the caps to arrive. :cool:
     
  7. mikiotty macrumors 6502

    mikiotty

    Joined:
    Mar 15, 2014
    Location:
    Rome, Italy
    #7
    You didn't kill anything :)
    Some of those capacitors in iMac G5s are intended to control the RAM amount or something like that, so with no capacitors (or broken caps) the iMac won't start/work properly.

    I've came across 4 iMac G5s in the past, all with bulging caps (one is sitting right next to me and working perfectly after cap replacement). The first one would crash with more than the onboard RAM inserted (20" iSight). The second one would randomly turn itself off, the third one would boot but no video at all and the last one would turn on and run the fans at full blast after 15 seconds, with no video. All working fine after cap replacement.

    It's definitely worth replacing them. They will ALL fail in the iMac G5s of all eras and all models. The tricky part is taking the old ones off the logic board, because the original tin is quite hard to melt. Put some new tin on it and put the soldering iron on the contact points for a couple of seconds, then gently pull them out the board. Don't try to melt the original tin only, it won't work :p
     
  8. stu232 thread starter macrumors newbie

    Joined:
    Mar 28, 2015
    #8
    Without a doubt this is the hardest board I've ever worked on. :confused:

    My soldering iron is really struggling to melt the solder even when using loads of flux and fresh solder. I've managed to remove the caps now I just need to get the solder out the holes. I'm tempted to use a fine drill bit on them, is this safe?

    I'm also hoping I haven't destroyed any tracks, talking of which where exactly are the tracks on this board are they embedded in a lower layer?
     

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