iMac G5 shuts down from Sleep mode

Per your suggestion, BDAqua, reset PRAM, downloaded and ran Applejack (auto). iMac seems to boot a little faster, but still. . .wake up = shut down. Could this (still) be Tiger / 512MB issue?

For memory, I'm looking at 1GB x 2:

http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=7822C914A5CA7304

Any thoughts?

Could this (still) be Tiger / 512MB issue?

I don't think so, I think some OS corruption from having the bad RAM, or something incompatible with some recent update myself, though low RAM and/or HD free space can make it much slower to shut down.

Any thoughts?

Looks OK, about the same as these...

http://eshop.macsales.com/Item_XLR8YourMac.cfm?ID=6077&Item=OWC3200DDR2GBP

I have had the same problem - iMac often shuts down when trying to revive from sleep mode using the mouse - since installing updates last week, specifically Safari 4.0.8 or Java for Mac OS X 10.4, release 9. I run Virus Barrier X5 and am confident I don't have any virus. I think this is a bug Apple introduced with one of their updates. One time, the system thought my USB mouse was a bluetooth device. It might be something recognizing the hardware. I had a similar problem after an update about 2 years ago (associated with sleep light update). Eventually Apple recognized and fixed the problem.

Two Crucial 1GB RAM sticks on order.

After installation, would you recommend I reinstall OS X 10.4?

I believe my problems, whether related to the bad RAM or not, came to a head in March this year. I replaced my failed Epson C86 printer; started getting the "gray screen of death" "you need to restart your computer" message which cleared up for a while after I removed a shaky USB hub. Eudora mailboxes got corrupted, lots of other little stuff, nothing serious.

I decided to reinstall OS X 10.4 but no longer had the install disk. They're hard to find! Ordered one from Apple and did an "Archive and Install". (I really like 10.4.11 and don't want to get into OS X 10.5 at this time.)

Everything hummed along smoothly after that until two weeks ago when the wake-up = shut-down problem started.

My question about reinstalling 10.4 again: should I do another Archive and Install? If so I'll then have two Previous System Folders at 2.5+ GB each. What do I do with them?

Thank you!

Currently the iMac will wake up after a few minutes in sleep mode. But if asleep more than ten minutes, shuts down with a keyboard or mouse wake-up nudge.

I'd reinstall, A&I should be OK. Once you're certain everything is there & working, you can trash those Previous System Folders & Empty the Trash.

Currently the iMac will wake up after a few minutes in sleep mode. But if asleep more than ten minutes, shuts down with a keyboard or mouse wake-up nudge.

That doesn't sound real good.

Take a look at these threads in the iMac G5 forum:

[Sleep becomes shutdown|http://discussions.apple.com/thread.jspa?messageID=9783472]
[Can't wake Mac from sleep|http://discussions.apple.com/thread.jspa?messageID=6743522]
[iMac shuts down when put to sleep, takes a long time to restart|http://discussions.apple.com/thread.jspa?messageID=9433611]

I had mentioned a possible power supply issue earlier - you might ask over there as well.

Thanks, jsd2. Don't think denial can keep me from taking a cold hard look at power supply issues anymore. Obviously RAM upgrade isn't going to solve my "sleep becomes shutdown" problem.

Due to the cost of power supply repairs and whatever else that entails plus cost of new RAM. I'm looking at refurbished or used iMac iSight. They say the iSight generation was/is problem-free

Thoughts?

Apple has a manual on how to replace a 17'' iMac G5 power supply:
http://manuals.info.apple.com/en/imacg517inch_powersupply.pdf

"Problem-free" is a tad strong for any computer ⚠, but I think the iSight did have a better power supply and was never included in the extended repair program. You could ask about this at the iMac G5 forum as well.

I don't know how prices compare, but unless you need to run Classic, I'd look to an Intel at this point, preferably a Core 2 Duo, possibly even a new Mini. Intel Macs are already much better performers, will become even more so with Snow Leopard, and there will probably be increasing numbers of new apps that are Intel only.

I agree with you. If I'm going to get a used/refurbished iMac, Intel is the way to go if/when I can afford it.

For now I've ordered a power supply and 2-512 Crucial RAM modules. Thanks for the link to the power supply install instructions--should come in handy next week.

Interesting occurrence this evening. Imac had been in sleep mode several hours. Didn't do the regular keyboard wake up. Plugged the scanner into the USB on the back of the iMac and it woke up. Didn't shut down. Strange.

You were right, jsd2, to point me in the power supply direction.

Replaced the PSU yesterday. Since then haven't experienced the problem of shutting down from sleep mode no matter how long or short it's asleep.

Also, you may recall, I had removed a bad RAM stick and was running on a single 512 module. Installed 2 new (Crucial) 512s after doing the power supply. So this iMac G5 1.8 is running like a two-year-old again.

Thanks for everyone's help with this problem.

Glad to hear it - thanks for letting us know. 🙂