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.
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
May 22 00:03:05 Fella kernel: Fan failure!
May 22 00:03:35: --- last message repeated 29 times ---
May 22 00:03:35 Fella kernel: Fan failure!
May 22 00:04:05: --- last message repeated 29 times ---
May 22 00:04:05 Fella kernel: Fan failure!
May 22 00:04:35: --- last message repeated 29 times ---
May 22 00:04:35 Fella kernel: Fan failure!
May 22 00:05:05: --- last message repeated 29 times ---
May 22 00:05:05 Fella kernel: Fan failure!
May 22 00:05:29: --- last message repeated 25 times ---
Is this a good question?