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CarloVonSexron
Jun 18, 2007, 09:19 PM
As the title says, my iMac G5 is not cooperating. Whenever I try to boot up, it goes to a gray loading screen with the apple logo and the loading gear-looking thing (heh, not sure what to call it). It sits there for a bit, then the fans get loud...and it continues sitting. I've repaired the disk and permissions and nothing has helped. Any other ideas before I take it to the Apple store?



Luigi239
Jun 18, 2007, 09:23 PM
You may want to consider running an Apple Hardware Test. (http://www.thexlab.com/faqs/aht.html)

CarloVonSexron
Jun 18, 2007, 09:47 PM
Thanks, doing it now. I'll let you know how it goes.

CarloVonSexron
Jun 18, 2007, 11:01 PM
Everything passed. What now?

Big-TDI-Guy
Jun 18, 2007, 11:06 PM
Reset PRAM? Not sure if it's the same process on a G5, so you should look it up here.

Unrelated (likely) But I had a similar problem, and mine (strangely enough) was one of the ram modules I installed was not completely in, and had backed out when I moved the Imac about a month later.

CarloVonSexron
Jun 19, 2007, 01:14 PM
I tried resetting PRAM with alt+Apple+P+R, and it did not restart while holding those buttons.

wrldwzrd89
Jun 20, 2007, 10:13 AM
I tried resetting PRAM with alt+Apple+P+R, and it did not restart while holding those buttons.
Perhaps you're doing it wrong. You restart the machine THEN hold down the keys. It should restart again. If it doesn't, that suggests you may have a dead logic board or something of that nature :eek:

mrzeve
Jun 21, 2007, 09:43 AM
Something is very fishy here.

Only a day ago the same exact thing started happening to me. I restarted the computer at random, and now it just sits on the loading screen with the spinner and Apple logo. I too have an iMac G5.

mkrishnan
Jun 21, 2007, 09:53 AM
Wait...I'm confused. If your Mac won't start up at all, how exactly did you repair permissions and repair the disk?

Perhaps you're doing it wrong. You restart the machine THEN hold down the keys. It should restart again.

Also, if resetting the PRAM does not help, try resetting the SMU (different thing). Instructions differ based on which iMac G5 you have, so read this:

http://docs.info.apple.com/article.html?artnum=301733

CarloVonSexron
Jun 21, 2007, 10:35 AM
Perhaps you're doing it wrong. You restart the machine THEN hold down the keys. It should restart again. If it doesn't, that suggests you may have a dead logic board or something of that nature :eek:

I hope not. The hardware test said the logic board passed. I will try the key combination again at lunch...what I did before was hit the power button and then hold the keys down.

Wait...I'm confused. If your Mac won't start up at all, how exactly did you repair permissions and repair the disk?

It hangs on the loading screen. I can get to the disk utility from the start-up disk.

sorryiwasdreami
Jun 21, 2007, 10:40 AM
My iMac G5's logic board and power supply failed a couple months ago and was covered by Apple's repair extension program for free.

I did not have Applecare.

Check it out; your symptoms could be the first signs of this happening.

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

mkrishnan
Jun 21, 2007, 10:45 AM
It hangs on the loading screen. I can get to the disk utility from the start-up disk.

Do you mean that you can boot off an install DVD and get into the OS X graphical installer, and thenr run disk utility, or do you mean that you are booting into single user mode and doing fsck -fy?

If you can run the startup disk and boot into OS X off of it, to do Disk Utility, I have a really hard time believing this is a logic board failure. It's far more likely that something is corrupt on the drive.

What about archiving and installing?

wrldwzrd89
Jun 21, 2007, 10:48 AM
Do you mean that you can boot off an install DVD and get into the OS X graphical installer, and thenr run disk utility, or do you mean that you are booting into single user mode and doing fsck -fy?

If you can run the startup disk and boot into OS X off of it, to do Disk Utility, I have a really hard time believing this is a logic board failure. It's far more likely that something is corrupt on the drive.

What about archiving and installing?

I agree... my best guess at this point is a corrupt BootX file or some other file Mac OS X needs to boot. An archive and install will fix this while causing minimal disruption to your data.

CarloVonSexron
Jun 21, 2007, 10:59 AM
Do you mean that you can boot off an install DVD and get into the OS X graphical installer, and thenr run disk utility, or do you mean that you are booting into single user mode and doing fsck -fy?

What about archiving and installing?

The graphical installer -> disk utility route. I will try archive & install over my lunch hour.

nuclearwinter
Jun 21, 2007, 11:14 AM
My aunt's iMac G5 has/had the same issue. The only way I could get it to start up was to pull the power from the back and hold down the power button. This resets the PMU.

You probably have either a bad motherboard or a bad RAM module. You can test the RAM theory by simply removing one module at a time and/or trying different RAM altogether. If the issue is bad RAM, you should hear 3 loud beeps and then the roaring fan.

The Apple store guys couldn't figure out what was wrong with my aunt's iMac. If you take it in, I hope you have better luck.

piedchaud
Nov 9, 2008, 04:58 PM
I tried to start many times - the fan or drive would start racing and filled me with fear of some permanent hardware injury.

Read your post from last year, remembered that I had just moved the thing 40 miles, and then brought it back! Opened it up and found one tab on one RAM slot was slightly askew. I reseated both pieces and used the opening of the machine as a good excuse to remove the small amounts of dust from ducts and vents.

It's working like a champ! (Mine's a late 2005 20" model that I bought used on eBay in 2006. No other problems.)

Thanks to this community for this as well as answers I've found that solved issues on previous Macs over the years.

Pied Chaud

Cmheath
Aug 28, 2012, 12:39 PM
I have the perpetual start-up grey screen + fan going into overdrive every so often with my iMac G5, and resetting the SMU and PRAM has taken care of the problem every time. HOWEVER, I have found it needs a little time to work things out, I.e., the grey screen continues to spin (appearing as if the resetting hasn't worked), but after 30 sec. to a minute or so, the system then successfully proceeds with its boot...exhale.

Macman756
Aug 28, 2012, 01:12 PM
I have the perpetual start-up grey screen + fan going into overdrive every so often with my iMac G5, and resetting the SMU and PRAM has taken care of the problem every time. HOWEVER, I have found it needs a little time to work things out, I.e., the grey screen continues to spin (appearing as if the resetting hasn't worked), but after 30 sec. to a minute or so, the system then successfully proceeds with its boot...exhale.

Why the hell are you resurrecting a 5 year old thread?!?

trewitt
Sep 23, 2012, 03:47 AM
A thread like this gets resurrected because someone is trying to solve a problem. An iMac G5 is perfectly good for lots of things, assuming that you have contemporary software to go with it. Look up "Wirth's Law" on Wikipedia.

Sorry for feeding the troll. Now back to the actual thread...

I don't know if it's applicable to this particular generation of PowerPC, but...
I've repurposed a lot of old Apple computers ("gumdrop" iMac G4s, but that was years ago). I *always* replaced the PRAM batteries (these were 1/2 AA batteries). One thing that I saw on occasion was this sort of "just won't boot", and when I replaced the battery it was all better.

On the iMac G5, the battery is cleverly hidden:
* Put the computer face-down on a pad.
* Take the back cover off (loosen the 3 philips screws at the bottom), lift that edge up - probably the easiest disassembly Apple's ever done.
* Remove the Airport card - 1.5" square in a plastic tray. The battery is underneath.
* Replace with a new 2032 lithium (standard PC "CMOS" battery, available in hardware stores, office supply stores - everywhere).
* The spring clip is crazy tight: you'll need to pry it up and then coax the battery out of the holder.

I still reset the System Management Unit:
* Unplug everything from the computer, including power cord.
* Plug in power cord while holding down power button in back. You won't hear any sound.
* Release power button.
* Push the power button to turn it on.
(This is fairly similar to the procedure to reset all of the SMUs on modern/Intel Macs.)

I still reset the PRAM:
* Push the power button.
* Push Command-Option-P-R quickly and hold until you hear the startup chime - and keep holding until you hear it a total of three chimes. (Three times sounds like superstition, but I read it in one of the Apple support notes.)

All that said, however...
I found this thread because I just pulled a iMac G5 that had been stored for 4 years out of my garage to donate it, and it had the same problem. Even with all of the above, it still won't boot beyond the spinning cyclotron of death + crazy fans. (Holding down the mouse button will eject the CD.)

I'll keep poking at it, though.

ihuman:D
Sep 23, 2012, 07:12 AM
A thread like this gets resurrected because someone is trying to solve a problem. An iMac G5 is perfectly good for lots of things, assuming that you have contemporary software to go with it. Look up "Wirth's Law" on Wikipedia.

Sorry for feeding the troll. Now back to the actual thread...

I don't know if it's applicable to this particular generation of PowerPC, but...
I've repurposed a lot of old Apple computers ("gumdrop" iMac G4s, but that was years ago). I *always* replaced the PRAM batteries (these were 1/2 AA batteries). One thing that I saw on occasion was this sort of "just won't boot", and when I replaced the battery it was all better.

On the iMac G5, the battery is cleverly hidden:
* Put the computer face-down on a pad.
* Take the back cover off (loosen the 3 philips screws at the bottom), lift that edge up - probably the easiest disassembly Apple's ever done.
* Remove the Airport card - 1.5" square in a plastic tray. The battery is underneath.
* Replace with a new 2032 lithium (standard PC "CMOS" battery, available in hardware stores, office supply stores - everywhere).
* The spring clip is crazy tight: you'll need to pry it up and then coax the battery out of the holder.

I still reset the System Management Unit:
* Unplug everything from the computer, including power cord.
* Plug in power cord while holding down power button in back. You won't hear any sound.
* Release power button.
* Push the power button to turn it on.
(This is fairly similar to the procedure to reset all of the SMUs on modern/Intel Macs.)

I still reset the PRAM:
* Push the power button.
* Push Command-Option-P-R quickly and hold until you hear the startup chime - and keep holding until you hear it a total of three chimes. (Three times sounds like superstition, but I read it in one of the Apple support notes.)

All that said, however...
I found this thread because I just pulled a iMac G5 that had been stored for 4 years out of my garage to donate it, and it had the same problem. Even with all of the above, it still won't boot beyond the spinning cyclotron of death + crazy fans. (Holding down the mouse button will eject the CD.)

I'll keep poking at it, though.

The iMac G3 has a gumdrop shape, the iMac G4 has a dome shape.