The PowerMac G5 is a desktop computer first produced in 2003 by the Apple Corporation. This guide will review the repair process of an Apple PowerMac G5 model number A1047 EMC 2061 from 2004. It was discontinued in 2006 as part of the Intel switch first to developers then consumers.

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Why does my Power Mac G5 power off suddenly?

My G5 Power Mac started randomly shutting down about 2 months ago.

It will run for weeks without problem, and then all of a sudden, it will just power off as if the cord was suddenly pulled out from the wall.

Sometimes, it is necessary to disconnect the power supply in order to reboot, sometimes not.

The /var/log/system.log shows a repeated Fan failure! message (see below for excerpt)

The power supply is usually connected to a power board that protects against surges. I also tried plugging directly into a power point via a standard extension cord - but same problem. I don't use a USP.

I installed temp monitor - it show 'memory controller heat sink' at 65-70C - not sure if that is a problem? Sometimes I have noticed that the CPU A temperate exceeds the 'Upper Limit' of 75

The fans don't seem to be a problem but I am not sure - I checked all the fans by booting up with the cover off, and all seem to be working OK. I guess there are fans in the heat sink which you can't see to determine if working.

I notice that the problem was worse during summer than now at winter, so maybe it is something to do with a thermostat overheating?

I ran the Apple Hardware test (from the CD that come with the MAC) - I initially ran it with the full compliment of memory but found that the fans went into a high rev, and the test (even the Quick Test) wouldn't complete.

So I uninstalled all but the original memory and ran both the Quick Test and the Extended Hardware test - both did not show any issues.

I had two internal hard drives installed - when I removed one of these, the power downs decreased making me think the unit is overheating with the extra drive?.

The Power Mac is under a desk with reasonable circulation around it front and back although it could be better. It was operating fine in the same position for 3 years prior.

Apple reseller says it is the power supply, but I think it is probably something to do with the thermostat closing the machine down.

Have reset the PMU.

Hardware Overview:

Model Name: Power Mac G5

Model Identifier: PowerMac7,3

Processor Name: PowerPC G5 (2.2)

Processor Speed: 2 GHz

Number Of CPUs: 2

L2 Cache (per CPU): 512 KB

/var/log/system.log:

May 22 00:03:05 Fella kernel[0]: Fan failure!

May 22 00:03:35: --- last message repeated 29 times ---

May 22 00:03:35 Fella kernel[0]: Fan failure!

May 22 00:04:05: --- last message repeated 29 times ---

May 22 00:04:05 Fella kernel[0]: Fan failure!

May 22 00:04:35: --- last message repeated 29 times ---

May 22 00:04:35 Fella kernel[0]: Fan failure!

May 22 00:05:05: --- last message repeated 29 times ---

May 22 00:05:05 Fella kernel[0]: Fan failure!

May 22 00:05:29: --- last message repeated 25 times ---

Answered! View the answer I have this problem too

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* Serial is YM424H1LQPM.

* I ran the Apple Hardware test (from the CD that came with the MAC)- is that the diagnostics you refer to? - I initially ran it with the full compliment of memory but found that the fans went into a high rev, and the test (even the Quick Test) wouldn't complete.

So I uninstalled all but the original factory installed memory and ran both the Quick Test and the Extended Hardware test - both did not show any issues. "Test Results - 43 Mins - Airport, Logic Board, Mass Storage, Memory, Video: Passed"

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Your machine is overheating and shutting down due to a fan failure and overheating as your system log indicates. Note - You cannot replace the drive fan and blower between the optical and hard drives. You must replace the enclosure for these parts.

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Thanks for your advice Mayer.

So, is the likely culprit the fan that sits on the top shelf between the optical and hard drives or could others also be faulty? I did observe these fans working but perhaps they are not working all the time.

Can you describe the 'enclosure' do you refer to in more detail? As parts are not available, would I it be possible to cannabilise a second hand G5.

Are there instructions available on how to replace the enclosure or is it relatively straightforward?

Thanks again.

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I don't know which fan is non-functioning. The note is directly from Apple implies the case. Please give the last three numbers of your serial number so we know exactly which machine you have.

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Run the diagnostic program. It will stop when it gets to the failed part and the text will tell you where you are. It will look like it has locked up but it's supposed to do this. The fans are supposed to run up and down and scream, they're being tested.

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* Serial is YM424H1LQPM. * I ran the Apple Hardware test (from the CD that came with the MAC)- is that the diagnostics you refer to? - I initially ran it with the full compliment of memory but found that the fans went into a high rev, and the test (even the Quick Test) wouldn't complete. So I uninstalled all but the original factory installed memory and ran both the Quick Test and the Extended Hardware test - both did not show any issues. "Test Results - 43 Mins - Airport, Logic Board, Mass Storage, Memory, Video: Passed"

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Apple Power Macintosh G5 2.0 DP (PCI-X 2) Specs

Identifiers: Mid-2004 - M9455LL/A - PowerMac7,3 - A1047 - 1969C

Are you telling me the problem goes away after you removed the added RAM?

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Hello, I realize this thread is old, however I have the same issue, EXCEPT NO error in the log regarding the fan.

In fact, no applicable errors.

THe system abruptly shuts off like the cord was yanked.

System diagnostics runs in loops with NO ERRORS.

I am at wits end.

Powermac G4 A1047 4GB ram.

Thank you.

Update

Well, nobody ever answered, but I think I found the issue. It has something to do with certain USB devices that OSX has problems recognizing. (even though they function, OSX cries about it in the logs)

As soon as I removed the offending USB device(s) the issue went away. Machine has been running for a few weeks without issue.

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It still does it. for no apparent reason. All diagnostics check out. Have run them in loops, no errors.

Yet, I can be using it (or not) and it will suddenly click off.

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Nobody? It will run for days, but for no apparent reason, Poof! it's off.

Sometimes it will shut off immediately after turning it on again.

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Hi Lee

Mine is the same

I have 5 of these computers stacked up, and 1 by one they act as you describe

I havent found the origin of the problem.but I wish I could

Thanks for your posts

Regards

John

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Dave will be eternally grateful.
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