13 Replies Latest reply: Jul 7, 2008 2:06 AM by MacMaui
dan weisberg Level 1 Level 1 (5 points)
My iMac was running fine. Shut it down to move it to another part of the room, hooked everything back up, and now it will not start at all. I'm guessing power supply issue.

If it is indeed the power supply, does anyone know how difficult it may be to replace it yourself, and/or how much Apple store technician or other certified repair would charge for this service? On my old PC's I had no issues cracking open the case for repairs, but have never done this on my Mac.

Also, would not mind upgrading to a new computer, but will Apple be able to transfer data from old hard drive without charging me for the power supply repair first - perhaps using a temporary power supply to make the transfer, or can the hard drive be hooked up in an external bay and used as a slave drive (I know this can also be done on PC's but not sure if it would work the same on a Mac, and a new iMac in particular.

iBook G4, iMacG4
  • dan weisberg Level 1 Level 1 (5 points)
    I'm wondering if this is more of a battery issue, since the computer was unplugged while changing the room around. While it was not that long - about 3 hours - I imagine on a 4-5 year old computer that could be long enough for the battery to die?
  • dan weisberg Level 1 Level 1 (5 points)
    Hopefully someone will chime in with an answer, but until then, my progress so far:

    Found a useful site (http://www.mrtotes.co.uk/mrtotes/iMac%20Flat%20Panel.html) with some detailed photos and instructions on taking apart the iMac. Also must thank Jukka Tervamaki from Finland for putting up a link to a since abandoned pdf that also details repair on the iMacs.

    Armed with the info, and picking up some tools, I cracked open the dome. First think I did was cleaned out all the dust - and there was plenty of it. But still no power. Nothing visibly loose or disconnected. Unable to properly test battery as my battery tester tests 3.0v lithium but not 3.6v. Since the battery os 5 years old, makes sense to replace it regardless of how it tests, and since a more comprehensive battery tester seems a lot more expensive than a new battery, I will just try to find a battery and replace it. After that it will likely be on to the power supply if the battery does not do the trick. Still curious if I can take out the hard drive and put it in an external enclosure and transfer data from it to my MacBook Pro or a new iMac.

    That's all for now - stuck until I can get a new battery.
  • dan weisberg Level 1 Level 1 (5 points)
    Continuing on with my soliloquy, I replaced the battery, and reset the PMU, but no power. So now I am at a crossroads - do I bother spending time and some money trying to find a power supply, not even knowing if that is the root of the problem, or do I bite the bullet and get a new computer? I guess my next step is to take out the hard drive and see if I can access the data through my MacBook Pro using an external enclosure.
  • Eustace Mendis Level 7 Level 7 (25,320 points)
    A suggestion: Verify the power cable is connected snugly and keep the computer plugged in for a few hours, perhaps even overnight. Then try booting.

    I would be skeptical the power supply died during the process of moving the computer, so replacing the ps would be the very last thing I would try.
  • dan weisberg Level 1 Level 1 (5 points)
    The power cable is as snug as can be, and I believe I had it plugged in overnight, but I will definitely try this over tonight and see what happens. I'm really at a loss - as I said in the beginning of the thread, everything was working fine, and now - nothing. If not the power supply, what else could it be?
  • dan weisberg Level 1 Level 1 (5 points)
    Visited Apple store to check out different power cord - still nothing. Leaving cord in overnight - nothing. Short of any other revelations, I will take out the hard drive for interim use and hunt for a good price on a power supply.
  • Niteshooter Level 2 Level 2 (450 points)
    Hmm kind of late into this but....

    Did you check the power outlet to ensure it is actually ok? Sounds simple but just in case.

    I'm also a bit skeptical that the power supply died just because you moved it, this feels more like the PRAM battery was dead and this caused the initial problem.

    Is the new battery known good? If so first try and remove all power to the iMac including taking out the PRAM battery and let it sit overnight. Now put the new battery back in and try restarting holding down cmd-opt-p-r as you are trying to reset the pram.

    If no go then it looks like the PS is kaput. Not sure what part of the world you are in but there are a few sites in the US that sell used parts. Sometimes you can find parts on eBay as well.

  • Jack Tomac Level 1 Level 1 (5 points)
    I've experienced almost the identical problem. G5 iMac shut down and moved. Plugged it back in and it would not power up. Tried changing batteries, still nothing. A local Apple tech told me to take the battery out and leave it unplugged overnight to make sure everything was cleared, sometimes this is better than pushing the reset button. I'll know more tomorrow evening when I put it all back together to see if that solved it. (But I'm not holding my breath.)

    Down side to this is that I've pulled the HD in an attempt to recover the data from it. Putting it into an external case was no problem but I can't seem to get it to mount on my current iMac. Any thoughts on what I might be doing wrong ? ? ? The pulled drive is an ATA V, which is what the external box is as well. So it should mount. Any software out there to force it to mount, similar to the old HD Mounter.....
  • dan weisberg Level 1 Level 1 (5 points)
    Yes, outlets were checked - several times over. Since my battery tester does not have a 3.6v setting, I can only hope the new battery (from Radio Shack) is OK. Will try other suggestions after backing up HD which is now hooked up to my MBP. I'm in US - just looking for a decent price on the PS and a few other items I may need to replace or upgrade as long as I have the whole inside apart already.
  • Niteshooter Level 2 Level 2 (450 points)
    Re HD in an external case, I'd check the jumper on the back first. The iMac is probably set to Master which is normal or perhaps CS for cable select. Mine was CS if that isn't working in the external case try and change the jumper to either master from CS or CS from Master.

    On the odd occaision that the drive won't mount try starting the Mac, then starting the external HD and then plugging the firewire or USB cable in. Also make sure you are on the desktop and not in a program though that issue is rare.

  • Niteshooter Level 2 Level 2 (450 points)
    Radio Shake should have battery testers. I would try both batteries. Granted if you only have a 3v tester and the needle blew all the way into the good range the battery should have been ok. If it only made it to weak or bottom end of the good range then the battery could be suspect.

    As for power supplies for a iMac G4 try, www.mac-pro.com (this site is handy because they have exploded diagrams and apple part numbers), I also like applecomponents.com but they don't have a PS listed right now.

    But I would try removing all power and see if that solves the problem first.

  • Jack Tomac Level 1 Level 1 (5 points)
    A little update. First, I resolved my external drive issue. A little stupidity on my part, I tried putting the ATA drive into a box that had a EIDE drive in it. Once I got an ATA box, it mounted right up.

    The second issue hasn't been so easy or lucky to solve. I removed all power, battery and power cord, for 24 hrs. I put in a new battery, put it all back together and it still doesn't power up. Absolutely nothing, no fan, no HD, nothing. I've found a site with a power supply but not sure if I want to go there yet. Weighing out the options of fixing and selling or selling as is.

    Thanks for everyones input. I'll keep monitoring this in case someone comes up with a solution.
  • MacMaui Level 1 Level 1 (15 points)
    I'm having exactly the same problem with a 800MHz 15" G4 LCD iMac, still running Jaguar. Very strange indeed.

    In my case, there was what turned out to be a fairly lengthy power outage (>3 hours). I wasn't home when it started, but my wife was using the iMac at the time and shut it down via the Apple menu command. (The iMac is connected to a UPS, so she had time to properly shut down.)

    I guess it could be the power supply, although I had the power supply replaced with a new one only a year or two ago. I tried resetting the PMU - it still wouldn't start up. The only other thing I could think of was to remove all the cords, take out the PRAM battery, wait overnight, and put it back together. Unfortunately, still no dice. (The old battery was at 3.5+ volts, but I replaced it anyway with a spare I had lying around which tested at 3.67 volts.)

    I'm now wondering whether it could be the power button itself that has "died" because of old age? Anyone know how I can test the power button to make sure it is working? I don't even remember when I last used the button to start the iMac -- I've been running Folding@Home on a 24/7 basis for several years now, so restarts are usually via the Apple Menu.

    I've put in a new hard disk, fan and power supply (maybe a new optical drive too - can't remember) into this iMac over the years, but it's now slow enough that I don't think I'd want to put much more money into it. It's a little sad, as it is still my favorite Mac design. I already have an Intel iMac, but I've kept the G4 around for browsing and email.

    Maybe I'll take the iMac apart again tomorrow and try squirting some contact cleaner in the power button to see if that helps.

    In the meantime, if anyone knows how to test the power button I'd appreciate the help!