My iMac keeps turning off

Happy Hollidays folks!
Well my G5 Imac started shutting off for no reason today. It won't turn on at all now. After a little research I found that many people have had problems with bad capacitors in their Imacs. I opened mine up and found that yes at least one of my caps in the power supply is bulging. I'm hoping the ones on the mother board are OK but I have my doubts.

To make things worse I found this:

http://www.apple.com/au/support/imac/powersupply/repairextension/

I didn't know anything about this but it seems I'm a little too late!
Hopefuly your problems aren't related but you might want to check those caps.

I found this pretty amusing, it may help some of you:

http://jimwarholic.com/2008/11/apple-imac-g5-power-supply-issues-and.php

Santa brought a memory upgrade so I took the back cover off to put in the RAM. I noticed all over the mother board caps that were bulging, not a great feeling. I did vacuum off the dusty spots although overall it seemed pretty clean. My system will run fine, even at 100% with the noisy fan, and not shut down. Then later on, I'll walk by and notice it's completely off. It's almost as if when powering off the display or something that happens when it's unused is making it shut off. I guess I don't want to believe it's the power supply but it probably is. I have figured out mine has the ALS feature which is a different part number power supply.

Hope everyone had a great Christmas!

OK here is my version of my power loss problems.
iMac G5 17" 2nd generation (w/light sensor)

I noticed about a month ago I would wake up in the morning to wake up the machine but come to find out that it was completly turned off. At first there was no problem getting it to turn back on. This happened only occasionally at first. Now this is happening almost everyday except now there are some other symptoms that go along with it. Sometimes when I go to power back up nothing happens at all. If I wait awhile longer and try again sometimes it will power back up. At this point it will either boot up normally or get stuck at the gray apple screen. If it gets stuck at the gray apple screen after about 30 sec - 1min the fans will kick into high gear, they will stay on high and the apple screen will stay there for as long as I let it. I hold the power button in to force a power down as soon as I am certain it will not boot up. If this is the case then I usually unplug everything from the back at all the usb ports and the Ethernet cable and unplug the main power connector. Upon reconnecting the main power connector and using the power button it will usually turn on correctly and everything works fine. However sometimes it still does not work, it seems to be completely random when it works and when it does not, however it is beginning to not work more frequently now so it appears to be getting worse. The last symptom I am seeing is sometimes after everything appears to boot up normally I cannot connect to the internet (I am using a cable modem, Comas), I know it is not the LISP connection becuase I can unplug from my Mac and connect directly into my work PC laptop and get right on. The only thing that seems to help is to reboot again (hope everything goes smoothly) sometimes it works right away other times it takes a few tries! Not sure if this is related to the loss of power problem or not??
I have been through all the steps in the Apple article "Mac G: Troubleshoot when your computer won't turn on" article # HT ( http://support.apple.com/kb/HT2173?viewlocale=en_US) and can come up with different results every time I go through it. It seems to be completly random as to what results I get.

I'm leaning towards a Power Supply unit or the logic board hopefully not both. Any idea what the cost of these repairs can add up to?

Any other ideas from some more experienced Mac users, this is my first Mac and it is only 3 yrs old.

Thanks,

Kevin

Wow Kev
I could of pretty much wrote all those symptoms. It started in the summer, I thought it was a problem with the sleep setting— sometimes when I tried to wake up the Mac, the power light would shut off but I could still hear the hard drive on and i would have to force quit by pulling the plug and then reboot. so I wasn't letting the computer sleep any more last week it would shut down out of the blue

I just brought my mac in for servicing on xmas eve because it would start at all the guy said it could be the power supply or logic board...

Make sure you Backup all your files!

Hi Shawn,

In Kev's case it sounds very much like a power supply to me. (the other problems he mentions are probably related to the directory and system file corruption that occurs as a result of the frequent sudden, power supply induced, shutdowns)

Problems when "waking from sleep", though, with the computer "hanging" (ie still audibly running but unusable) of the type you mention though can have a variety of causes ranging from problematic software or third party peripherals through to logic board issues. If it is hardware, then it is probably the logic board, rather than just a power supply, I'm afraid, especially given the model of iMac G5 that you have.

Rod

You are right Rod
Service guy said it was the logic board... bulging capacitors. and it would probably need a new power supply too. Total cost: $900
I just went out and purchase a new imac 3.06 ghz /4gb memory.

BTW
My disk warrior is still in the drive slot of the dead computer. Is there an easy way to get it out?

That's bad news Shawn. There are actually substantially cheaper ways of getting the capacitor issues repaired, ( http://www.synaptech.com would certainly be contacting) by the way, but heck those new iMacs are pretty smooth!

If the iMac will power up at all (even if it won't fully boot up) then you should be able to remove the DW CD by starting up while holding down the mouse button or the eject key on the keyboard.

Cheers

Rod

Well the bright side is this new machine rocks.
and I was surprised how easy it was transfer and update files.
(mainly because I had backed-up everything on an external HD)

I still can't the disk out— it power ups for a second and then shuts down.

Try letting it cool down , removing the power cord to the computer, for 12 hour or more and then attempt the eject routine using the mouse button or eject key at the very first startup. The cooler the power supply is the longer it is likely to be able to supply power - all you should need here is a few more seconds. I'm afraid there is no hidden "eject" mechanism on the iMac G5 optical drives that I've seen.

The other option is to remove the drive , attach an external IDE/ATA interface or enclosure, and eject the disc from there.

Rod

Thanks for the info Rod
Won't power up at all now
I guess Ill have to find an external IDE/ATA interface. Can I also use the same interface for my the HD in my old imac?

The HD runs off the SATA bus (and needs a SATA enclosure or connector ) while the Optical drive runs off the (P)ATA bus (with its own type of connector).

Most enclosures and adaptors provide only one type of drive interface, though there are a few around that offer both - Bear in mind that if you want to use an enclosure, rather than just an interface, you will need a larger case for the optical drive than you would need for the 31/2" HD, too.

Cheers

Rod

Happy New Years Rod
Thanks for all the info, much appreciated!

Happy New Year all,
Just last evening I was bragging to a PC owner who had multiple and repeat problems with Dell hardware how reliable Apple hardware was. I didn't mention that starting about a week ago I started having problems with my iMac G5 20" 1st Gen - the power started going off for no reason. I was confident I would find a fix settings fix, or reasoned that if it WAS a power supply, they can't be expected to last forever.
This forum was very illuminating...thanks to all. I find I am having my Apple enthusiasm somewhat dimmed.
I am struck by few things:
1. I never heard about the extended warranty.
2. Presumably Apple thinks there's a problem with iMac power supplies.
3. I chatted with an Apple rep a few days ago who went through the SMU PRAM/NVRAM reset litany, never mentioned that there has been a wealth of experience with power supplies (as confirmed by over 500 views to this specific forum).
4. Sounds like a lot of folks are having this problem.

While not entirely opposed to purchasing a a new iMac, I expect a transcontinental move in a year, and was hoping to find a way to keep the family computer going for another year so as not to subject a new computer to the perils of a move. I live in a country where I am not comfortable in the local language...not always easy to get proper repair work done.

Questions: Has anyone had a new power supply installed by an Apple rep go bad again (as insinuated is possible in the linked article)?
Is there enough owner interest in this issue that Apple wil reinstate the extended warranty program?

Thanks

I'm also having the same problem, I reset the SMU and PRAM twice, following all the advices from this post, but I'm having same issues it shuts down by itself and I have to wait 10 minutes before turning back on again,
Can anyone tell me if they solved the problem and how?
also I need to check the temp on the imac g5 but I don't know were to start can someone tell me.
Thanks in advance.