Fans were found on full blast during sleep. Mac wouldn't wake. No entry symbol on next startup. Ran AHT & utilities managed to restart, but fans sounded a little louder. Noticed it was running on only one CPU.
Ran more tests, removed RAM and other addons, did PSU & PRAM resets etc.
When starting after being left both the CPUs would work before crashing back to one.

I found a manual on the net & took it apart to clean & reassamble. It worked for a few days then the same thing happened.

Local Apple Genius bar said 'It could be the CPUs or main Logic board failure'. I can't afford the possibility of replacing all those parts.

Suddenly failed - failure to start up, freezing on grey start-up screen, turbo fans, random freezes when in use, kernal panics. Machine unusable.

Apple Geniuses diagnose either faulty logic board or processors - Applecare expired 4 months previous - quote between £500 and £850 to repair which I will not be proceeding with - Machine now useless.

Logic board replaced after 18 months under Applecare.

It stoped booting. Freezing because of cpu heat up. I need to change cpu. It will cost me 2200 Can$..

they did change power supply. They change LB to try if the problem was coming from it.

After a Leopard upgrade, the machine was balky and finally displayed a grey screen together with overspeeding fans.

The techs at my local Apple stoere ran a hardware diagnostics test and then replaced the primary hard drive. The machine still wouldn't boot up.

They then surmised the problem as a logic board failure and recommended replacement of the logic board and processors and power supply, to the tune of "at least" US$1,500.

This machine was bought new from Apple and has been in one room for its entire career as a lightly- and infrequently-used FCP editing station, always with a large external fan blowing into it.

Both its failure, and Apple's inability to trace the fault to a particular component or specific spot on the logic board, leaves me with major questions about their machines' usefulness as professional tools.

My intention is to seek compensation through the court system, using both a defective design legal theory and a deceptive trade practices legal avenue.

during an Apple software update in Sep,
the screen frooze,
and fans came on full blast.
it never turned back on again.

nil

nil

nil

the first symptom was that the machine would freeze on wake up...This happened for a couple of weeks.... I ran the usual fixes ie reset pram and fixed permissions...
Then I left it powered down and unplugged for 3 weeks while I was overseas...
On powering up it failed to boot... I then tried several different ways to get the machine to reboot ,like resetting the Pram on bootup and booting the hard drive on another machine in target mode.. the hard drive seemed fine and the G5 would boot up some times but then it just failed altogether :(

I took it along to the Apple tech service centre where they ran all sorts of tests ( I have full documentation) to much to go into here I could post it as a file if any one is interested.... The up shot was that the service tech reformatted the HD.. reseated the CPU's...re calibrated the thermal processors.. Did a clean install and ran a stress test for more than 12 hours.... The machine still failed... so he removed the HD and booted from an external firewire HD... this got the machine working... Sort of...
As it stands at the moment I can only boot from the firewire Drive and it wont sleep
also the monitor keeps flashing... the Tech suggested I buy a new Logic Board but offered no Guarantee that it would fix the machine... all it is good for now is getting my emails..... :[ ps it wont run any pro software with out freezing...

NIL

This Machine was used in a very clean environment and was spoken to well it also received the respect any high end machine deserves... :)

got a kernal failure, restarted and now nothing happens. Light flashes 3 times and pauses, 3 times - pauses...etc. Reste the button inside and pulled the plug, moved around RAM removed extra drives...still nothing

never any problems

Hidding the start button will only start the fan. Mostly you can hear some kind of a klick inside the sytem. After this nothing else happens: no chime, no HD-action, no video signal... Nothing. And as soon as the button is released the LED turns off.

AASP said the logic board has to be changed. It's definitely not the power supply. They tried a new one and it wan't help.

Problems while booting happens for the first time more or less immediately after I bought the machine this summer. At this time I was experimenting with various HD's and displays, so I thought that this caused the problem. In the beginning the computer booted after a few tries. But it became more and more. After a period of relativ stability the Mac seems to went dead in September. I brought it to a free workshop and they give it back to me still running, claiming that it was a unique firmware problem. But at the end of November the symptom reoccours. The workshop couldn't help it so I contacted a local AASP, that made the sad diagnosis.

The machine is from June 2004 - so the trouble begun shortly after the G5 became 4 years old.

I thought the fans were louder a couple of months ago so I installed istatpro and checked the numbers with what some other people had posted on message boards and it seemed to be normal. I hit the power button and walked away one night and when I came back the fans were running and the status light was on but that was it. I turned it off at the power strip, turned it back on and reset the PRAM and it booted but after five minutes it froze. I turned it back off again and after that all it would do is turn on the fans and blink three times.

I didn't take it to the Apple store because I've always done business with a local reseller. They said it wouldn't work no matter what RAM they put in so they recommended a new logic board ($860 including labor), which I agreed to because it was cheaper than a new computer. I asked repeatedly for details about what specifically had gone wrong but they had no clue.

I'd never had a problem of any sort before this. To the best of my knowledge I'd never even moved my Mac a millimeter since I first got it.

freeze. Black screen at startup before grey apple. no keyboard, no mouse.
(1 or 2 times until grey Apple but without spinning gear)

10.4.11
;
disks are good on my other mac (MacPro)

- try zap & PMU => idem
;
- try start on CD => idem
;
- try remove HDD but first => idem
;
- try remove one bank of memory (from applestore) => idem
;
- try remove the other bank of memory (from applestore) => idem
;
- try without battery => idem
;
- try to clean dust inside including alimentation => started again but idem again after 20 hours non stop
;

AppleStore France purchased
;
near 24h/7j on since 2005

After a reboot for security update 2008-08 the system came up to the blue spinning wheel and never made it any further. No symptoms prior to that.

Not yet.

The super drive was replaced under warranty.

Whilst printing the machine crashed (Kernel Panic). Fails to restart untill cooled down, and when succesful restart, will only run without freezing for about an hour.

Superdrive repaired under warranty

Have Tried:
DU + Applecare Disc report no hardware / software failures.
Restarted into Single User Mode. Ran Applejack. No problem reported.
Stripped out all third party cards.
Stripped out RAM chips and rotating to diagnose if 1 pair faulty.

When Computer warm, have tried restarting in Single User Mode after a freeze - Still no joy - freezes before it gets to the Prompt
Reset PRAM.
Reset CUDA.
New Internal Battery installed.
Reset Open Firmware
Swapped out Graphics card with a working G5 machine. My machine still freezes.
Replaced Hard Drive with new Western Digital Drive and installed OS10.4 +Combo Updater. System worked for about an hour then froze. Repeated Process with Seagate Barracuda Drive. Same thing happened.
Run Hardware Monitor, and note that temperature of both CPU’s will suddenly spike from 42 degrees (temp after 15 mins running) to 55 C and cooling fan will switch on for approx 5 secs. Temperature reading is ‘spiking’ and resulting fan activity can be bought about very easily by rapidly resizing the 1 open window in Hardware Monitor.

Froze completely during normal operation. Fans went on high, would not respond to keyboard. Had to shutdown using the main power button. Would not reboot. If restarted, then froze on grey screen, fans on high. Got kernel message once. Would not reboot without freezing.

I replaced the logic board battery, froze again. Reset the PRAM, froze again. I have tried reseating the RAM, taking out the HDs and reseating them, ditto on the video card. I have been able to backup info from the HDs, but the CPU would freeze after 5 minutes and I had to do a hard shutdown. Tried off and on for a week to get it to restart to attempt to back up data. Read all threads on this issue online and finally took CPU to Apple Store on 11.26.08. Genius diagnosed a video issue, ordered a new card.

This machine was bought new in 2005 and has never traveled or left the room it was set up in. It has never had any repairs or issues. Two days after I left it at the Apple Store, the new card hadn't come in so I picked up the CPU & installed a new card at home, didn't work. Just froze again. All that's left to try is a new (used) logic board, but they are hard to find and there's no telling what shape they're in. I am severely disappointed in the premature death of my G5.

Same as others.

Leopard update caused Grey screen and fan over-cranked.
Would not boot.

Applecare avoided all assistance.

I suspect Apple does not want to support any pre-intel machines. Particularly large expensive ones. Leopard clearly started the problem and I believe recent update created the catastrophic breakdowns.

Our Mac consultant called it: Logic board/Processor failure.

Prior to this none had been required.

This issue was red-flagged at Applecare.

A Class action law suit should be considered.

Encoding video, I left the room for maybe 20mins tops.
Came back to a kernel panic(system failure) "corrupt stack on CPU-1" with fans running full throttle.
Then it refused to boot giving me a black screen, then a gray screen on subsequent attempts.
Then the no entry symbol and kicking the fans on high again.
Swapping the physical locations of the CPU's and removing PROM battery allowed the system to boot with 1 CPU, fans still running high.

After a few weeks the system just stopped powering on altogether.
Only way to boot it is to apply heat to the lower left corner of the logic board, and then it freezes up unless I disable 1 of the CPU's using the CHUD tools preference pane.

Failed logic board.
By process of elimination.

Had the LCD module in the cinema display replaced about 1.5 years ago.
Had the suprdrive replaced about a year ago.
Those repairs were done when the applecare plan was still active.
My applecare plan expired about 4-6 months before this problem occured.

There were no signs before one day the computer would not startup. At startup it still gives the startup chime and the fans start spinning, the harddrives start to spin and the cd rom spins a little but after 5 seconds everything becomes quiet and the display stays black (it never had a grey screen). Then after 2 minutes or so the fans start to spin faster and faster.

logicboard has to be changed

Before total failure nothing was ever wrong with this computer. I too never travelled with this machine and only made some music with it. It didn't stay powered up long times

I used panther and Tiger on this machine, never Leopard

Constant freezing, followed shortly by no boot. Front led panel flashes 3 times to indicate bad ram. Ram has been checked and rechecked.

Took it to Apple store, booted fine after not working for weeks. Got home, it wouldnt boot again. Returned to Apple store, they told me i needed a new logic board

no repairs done

Was able to boot for a few days by heating up the logic board around the DIMM slots. Now its dead forever

Firstly a sudden freeze followed by great difficulty in booting. Only starting up intermittently, mostly no chiming. Now not starting at all. Checked drives whilst still bootable, all ok.

Three flashes on the front panel LED which indicates mismatched RAM. Tried all the RAM strips a pair at a time to determine faulty pair. RAM ok. Machine suffering with logic board failure in respect of CPU not contacting the RAM, as with many other machines of this vintage.

Apple replaced noisy power supply in first year. Apart from that the machine has never left the spot where placed when first purchased.

Came home after walking the doggy. Heard the fans reving at full throttle. Saw gray kernel panic screen. I (in turn) panicked and did a hard shut down. Rebooted and same thing happned again after a few hours. While installing the 10.5.7 update (thinking it would fix the kernel panic's) the computer froze again and hasn't been running on 10.5 since. I successfully installed 10.4 on a free partition on my system drive and I can boot up with 10.4, but practically nothing works withouth freezing the system. I have no sound and the video screen is choppy sometimes... I don't get gray screens anymore either - the computer just freezes.

I have tried the basics. Reinstalling OS, reinstalling RAM, removing USB/FW devices, tried different HD's with different OS installations - etcetera ad nauseum - to no avail.

PowerMac froze while working, after trying to restart, it would not pass the apple logo (grey screen), after a while the fans would go full speed and then it would turn itself off.

Can only get into the open firmware, but after issuing the 'reset-all' command it would just sit there and do nothing.

It has booted up fully once, i could rain disk repair and saw that both CPUs where working, but after a restart it would go into the same situation again.

Ran AHT and ASD discs myself, both say all is oke, no official diagnosis.

No repairing history.

Mac OS X Leopard latest (i believe 10.5.6?)
Radeon X 800 XT 256mb
220GB HDD in RAID 0 (2x120Gb)
2.5GB RAM