12 Replies Latest reply: Aug 5, 2010 5:59 AM by RubenSchouten
dapnoyqpid Level 1 Level 1 (0 points)
Hi all! Before posting I made sure to read as much as I can in this forum & various sites so that I won't be repeating a previous post. So I apologize in advance if I do. So on to my problem…

When I press the power button on my iMac G5, the chimes go off, but the screen stays black. Then after a few minutes, the fan goes full blast. Here are the different things I've done.

a. Plugged and unplugged the power cord and used different outlets.
b. Reset the SMU
c. I followed the instructions from http://support.apple.com/kb/ht2173 (I don't know if this matters but LED 1 and 2 light up)
d. I inserted the "Mac OS X Install Disc 1" to run Disk Utility but nothing seems to happen when the disk is inside (I do hear the CD being read and spun around). I couldn't get passed step 1 with the instructions from this previous post http://discussions.apple.com/message.jspa?messageID=11426662

I've had problems in the past and most of the time it's fixable. But nothing seems to be working now. Are there any other tips or suggestions you all might have?

Thanks for your time, I greatly appreciate it!

iMac G5 PowerPC
  • 1. Re: iMac G5 will chime but won't do anything else…
    MGW Level 7 Level 7 (27,000 points)
    If Disk Utility won't work and you can't boot from the install disk, it's either your logic board or your hard drive, my money is on the logic board. It sounds as if you need to take it in, sorry...

  • 2. Re: iMac G5 will chime but won't do anything else…
    dapnoyqpid Level 1 Level 1 (0 points)
    Thanks so much for the fast reply Miriam! But before I take it in to the Apple store, is fixing/replacing the logic board a doable task? I'm not an expert but also not an amateur. I follow instructions well.

    Thanks again!

  • 3. Re: iMac G5 will chime but won't do anything else…
    MGW Level 7 Level 7 (27,000 points)
    Take a look at [xlr8yourmac.com] for tips, also look at [synaptch.com] for help in getting parts.

  • 4. Re: iMac G5 will chime but won't do anything else…
    macbig Level 4 Level 4 (1,680 points)
    Most of the logic board problems in the iMac G5’s appear to be capacitor issues. Here’s a site that will help you id the culprit(s) and DIY instructions: http://jimwarholic.com/2008/07/how-to-repair-apple-imac-g5.php
  • 5. Re: iMac G5 will chime but won't do anything else…
    Jeff Kelleher Level 4 Level 4 (3,015 points)
    If the capacitors are the issue, Apple will just replace the logic board/midplane assembly, and that is not an inexpensive fix. Replacing bad capacitors yourself (if that's the issue) is an option, but it requires knowledge and experience in soldering electronic components. If your iMac is not working, I suppose you have nothing to lose, but just realize that if this is your first time tackling such a project, your chances of success are at best, equal to your chances of failure.

    If your determined to save this Mac, I'd try to find an authorized repair shop willing to try to help you out. Some shops will just follow Apples procedures, and tell you to replace the logic board, or whatever part contains the bad capacitors, assuming that is the problem. Some shops may be willing to try to fix the capacitors. It really comes down to what you're willing to do to try and save an old Mac.

    Replacing the logicboard is fairly doable, provided you can find the part.

    Take a look at the great links already provided, and look at the prices for replacements on ebay (or anywhere else the links or Google may take you) and decide what you're willing to spend to try to fix your Mac.
  • 6. Re: iMac G5 will chime but won't do anything else…
    dapnoyqpid Level 1 Level 1 (0 points)
    Thanks again for the responses everyone!

    Jeff - it would be my first experience soldering electronic components, so it's a bit daunting. Just reading posts and surfing online, I feel that the replacement would be as much or close to buying a new system.

    The most important thing for me is if I can somehow retrieve the files that were on my hard drive. Unfortunately, I haven't backed up most of my files. I now know to never make that mistake again. A friend suggested making the internal hard drive into an external. Is that even possible? And have any of you done something similar to this?


  • 7. Re: iMac G5 will chime but won't do anything else…
    spudnuty Level 5 Level 5 (5,250 points)
    So everyone has given you very good diagnosis and repair paths. If you look at Jim Warholics site and determine that you have bad capacitors. (Be aware that just a tiny bit of doming will indicate a bad capacitor.)
    So if after you survey all the capacitors in your iMac you find that you have just a few bad ones you can buy the kit from Jim and attempt your own repair.
    Read this thread first:
    Now I recently got 2 iMac G5 20" 2.0 GHz machines donated that both had the capacitor problem. They both had the RAM maxed out at 2 GBs so I was licking my chops as they were sorely needed at the school for a video GarageBand class.
    I took both of the backs off and surveyed the capacitors. One had two bad ones but the other had 12! I actually had a bad 2.0 GHz 20" iMac w/ a bad power supply sitting in my "to be repaired" area. It also only had two bad caps on the logic board.
    In starting the removal of the two bad caps I was reminded how difficult this process was so I just heated the through board leads until I could move the leads up to that I had about 1/4 inch of a gap between the bottom of the cap and the logic board. I then cut the leads off as close to the bottom of the cap as possible and tacked soldered the new caps on. I used a Xacto knife to do the cutting. Be very careful of fingers and don't cut the logic board (Did that on an old G3 iMac and it was very dead afterwords) or damage any of those tiny SMT parts.
    Here's some pictures:
    http://s291.photobucket.com/albums/ll306/spudnuty/iMac%20G5%20capacitor%20repair /
    Turned out these caps had to lay down since they were in the area where the spring loaded box where the foot attaches.
    Those two iMacs are now back in action and ready for the summer camp video students.
    The one with the 12 bad caps is now at the back of my "to be repaired" area waiting for a day when I'm really bored with nothing to do.
    Good luck.

    Message was edited by: spudnuty

    Message was edited by: spudnuty
  • 8. Re: iMac G5 will chime but won't do anything else…
    MGW Level 7 Level 7 (27,000 points)
    Making the hard drive an external is quite simple - buy a case from [Macsales.com], they will sell the the proper tools as well and all you need do is remove the drive from the iMac and put it in the new enclosure. Make sure that you have both firewire and USB, and if you are getting a new iMac, firewire 800 and USB2. You can also get a bare drive dock, but I prefer enclosures, they protect the drive better. Once you have transferred your data, you can use the new external as a backup drive, with SuperDuper!, which can schedule backups for you. In any case, it is,as you have now found out, imperative to have a backup/clone.

    Let us know how you do,

  • 9. Re: iMac G5 will chime but won't do anything else…
    dapnoyqpid Level 1 Level 1 (0 points)
    So I have an update, after inspecting the logic board I didn't find any bulging or leaking capacitors at all. So I decided to dig a bit deeper and open up the PSU. And I found a few bulging and leaking capacitors, and the shell that covered them had a black residue (similar to when you place a piece of metal over a candle). Here's an image of the capacitors in the PSU: http://img143.imageshack.us/img143/6923/201006051821522.jpg

    Hoping that the problem is only the PSU, I ordered a replacement on eBay ($98). Although it would be cheaper to replace the capacitors myself, I don't think I would be successful at soldering. I'll post another update to let you all know if this fixes my iMac problem.

    And thanks again to all who posted! Your replies were very helpful and informative and I appreciate it!
  • 10. Re: iMac G5 will chime but won't do anything else…
    dapnoyqpid Level 1 Level 1 (0 points)
    Update: I received the PSU in the mail today and replaced the busted one. But unfortunately that still didn't help. The same problem persists. So it's definitely the logic board or the hard drive. However, I didn't see any bulging or leaking capacitors like I did with the PSU.

    Is there a way to find out if it's the hard drive that's causing the problem?

  • 11. Re: iMac G5 will chime but won't do anything else…
    MGW Level 7 Level 7 (27,000 points)
    Have you tried putting the hard drive in an external and mounting it on another computer?

  • 12. Re: iMac G5 will chime but won't do anything else…
    RubenSchouten Level 1 Level 1 (0 points)
    I have the exact same problem and determined that it is not a harddrive issue by booting into open firmware (hold AltCmd+OF while powering on). I was able to access and read data from the harddisk from the open firmware, so the harddrive is functioning properly.