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Leaking Capacitors in iMac G5

Discussion in 'PowerPC Macs' started by keysersoze, Sep 21, 2007.

  1. macrumors 68000

    #1
    I just opened up one of our iMac G5's (Rev. A) to install memory yesterday and saw 2 leaking capacitors and 2 bulging capacitors. :eek:

    Turns out Apple had some problems with these awhile back and have an extension repair service, but this machine does not fall under that (it's a refurb).

    In any case, I have no idea how long they've been bad, or if they are a risk (fire?). The machine seems to run just fine.

    Should I be concerned about this? We don't want to replace the logic board for $900. I don't want to try to replace the capacitors, although some people have done it succesfully.

    Any input appreciated.
     
  2. macrumors 65816

    bmcgrath

    #2
    Ring Apple.
    See what they say
     
  3. macrumors 68000

    #3
    They said it's not under warranty and a logic board repair would cost $900.
     
  4. macrumors 65816

    bmcgrath

    #4
    Oh right. Sorry.
    Hopefully another member can point you in the right direction so and help ya
     
  5. macrumors 65816

    Luap

    #5
    My rev a G5 iMac had this problem too. I started to get video artifacts, that gradually got worse and worse, then the mac would lock up completely after a short time.
    It was only just inside the warranty period when this happened. Still, it was repaired and has been fine for 2 years now. The repair guys did mention it was the caps that had failed, in the same manor as you described. But of course the boards are not serviceable by Apple, even for just simple/cheap components like caps. So the entire mobo was replaced. Bit of a waste, but there you go..
    I imagine for someone with competent soldering skills, it would not be too hard or expensive to fix though.

    I dont want to put a downer on things for you, but the failing caps will affect the operation of the computer sooner or later..
     
  6. macrumors 68000

    #6
    That's OK, we're resigned to that... eventually it will just die. I'd like to be able to solve such a cheap-o problem cause I've heard caps are really inexpensive, but I just don't have the time or expertise. I think the whole computer would have to be taken apart which could likely lead to an even earlier death of it.

    I guess we'll just run it until it completely chokes, unless someone says it could be hazardous.
     
  7. flipperanubi, Sep 21, 2007
    Last edited: Feb 24, 2011

    macrumors member

    #7
    a
     
  8. macrumors 68000

    #8
    Any body on these boards have any experience replacing caps? :confused:
     
  9. macrumors regular

    #9
    Cut the damaged capacitor forcefully through the middle (horizontally) with a side cutter. Then try to carefully remove its lower half while preserving the two pins connecting it to the logic board. The longer the pins' length the easier soldering will be. Remember which pin is plus and minus (printed onto the original capacitor). Bend the pins apart a little and cover them with solder (don't let it get hotter than needed). Do the same with the replacement capacitor's legs. No need to cut them as short as the original ones. Just leave 'em as they got shipped. Then solder each leg to each pin remebering which was plus and minus. Now carefully separate both pins with insulating tape. Then wrap tape around both insulated pins together and the capacitor. Finally carefully bend the whole package into place to make it fit into the case again.

    Exercise maximum caution that the insulated pins don't touch each other and that the tape doesn't shift while bending the package into place!

    Instead of $900 just a few cents and a little bit of spare time. It really isn't that hard.
     
  10. macrumors 65816

    Luap

    #10
    Any chance you can take a pict of the failed caps?
    Its something I could probably repair myself, if it happened to my iMac again. But im in the UK, so likely no use to you.
    There was a very similar problem with the MK1 Apple airport base stations some years ago. I ended up fixing 2 of those base stations myself. Again, failed caps that were quite visibly knackered.. Bulging and leaking gunge.

    But again, anyone with moderate computer experience and good soldering skills could probably have that fixed quite easily and cheaply. I'd really be surprised if the parts alone cost much more than $10

    If you have a google around, you'll find quite a bit of info on the problem. Heres one i found just now..
    http://www.macnexus.com/index.php?option=content&task=view&id=306&Itemid=2
    This also contains a link to www.badcaps.net which documents the problems across many manufacturers, not just Apple. It seems they also offer a repair/recapping service.

    While im here, I doubt the machine will be in any way dangerous to use.
     
  11. macrumors 68000

    #11
    That sounds a lot easier than what I read on badcaps.net. They seem to advocate pulling out the entire old cap rather than reusing the old caps legs. Won't chopping a bulging capacitor in half leak electrolyte? Or does the bulging indicate it's already 'solid?'

    I agree if it can be done, it's worth doing, but I'm not expert at this. Maybe I'll find someone who is.
     
  12. macrumors 68000

    #12
    Thanks for all the info! Unfortunately I don't have a camera, but I bet they look just like how you imagine them to... :)
     
  13. macrumors 65816

    Luap

    #13
    In that 1st link is a pict of a board with failed caps. Probably looks much the same as yours does?
     
  14. macrumors 68000

    #14
    Yep! 2 look just like that. 2 others have brown crud all over the tops.

    That first article had some great advice "If you suspect bad caps, don't put your face near them while the system is powered up, and don't eat the paper or electrolyte that they blow out!"

    LOL
     
  15. macrumors regular

    #15
    Yes. It's really much easier and safer. Of course it can still contain liquid. I just implied that you clean up any mess the whole procedure would have caused. Wrapping the capacitor into toilet paper while cutting is also a good option.
     
  16. macrumors 68000

    #16
    Well that's very good info. I think I will crack the iMac open later and see how much legs those capacitors have to work with.
     
  17. macrumors regular

    #17
    Usually if it is industrially manufactured, like your Mac, they will be very short. But that's the trick of cutting through the whole package. Usually the legs continue up a few milimeters inside the capacitors before they are connected to the foil and you can take advantage of that.

    I would advise not turning on your machine anymore until this is fixed. The broken capacitors can lead to the destruction of other components as transistors. As soon as they fail, the board is practically worthless as there is no way anymore to identify the broken components visually (as easily with capacitors).
     

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