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PowerMac G5 with fan problems. Is my diagnosis correct?

I was hoping that someone could confirm my diagnosis of problems on my Powermac G5 2.0 GHz dual. It's one of the original ones (bought in May 2004). For a while now I've been having problems with the computer not waking from sleep, fans at full speed, shutting down unexpectedly, etc. I got hold of an ASD 2.5.7 disk and ran the tests. Everything passed, so I tried a thermal calibration (I hadn't changed CPUs, but I have had them out for cleaning a few times). The calibration failed with the messages:



Calibration start CPU0

ERROR CPU0 - Processor 0 ID EEPROM checksum error

Replace Processor CPU0



Calibration start CPU1

ERROR CPU0 - Processor 0 ID EEPROM checksum error

Replace Processor CPU0



so it appeared that Processor CPU0 (the upper one, I believe) is bad.



I opened the machine, and switched Processor places, then tried the calibration again. This time CPU0 calibrated successfully, but CPU1 (which was CPU0 on the first try) failed with the message:



ERROR CPU1 - Check that outer door is securely closed and recalibrate

Ambient Temp Sensor (IC2) is located on main logic board.



I was confused about that last, because it didn't say anything was wrong with the Ambient Temp Sensor.



I then switched Processors back to the original positions, and got the same Errors as the first test above (i.e., EEPROM checksum errors on CPU0).



I'm taking this to mean that the logic board is okay, but that one CPU (the original CPU0) is bad, so I need to replace it.



Does that sound right?



Thanks in advance for any help.





-Aron

PowerMac, Mac OS X (10.5.8), original PowerMac G5 2.0 GHz dual

Posted on Nov 29, 2012 12:35 PM

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Oct 20, 2018 1:09 PM in response to japamac

Thanks, japamac, for the quick reply. I have another question. I ordered a CPU, so I'm waiting for that. The computer still works, after a fashion, but now the fans go full speed all the time. Am I risking damage to anything if I keep using the computer with the fans running like that?


Thanks again,


-Aron

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Oct 20, 2018 1:09 PM in response to Community User

Thanks westerneyes and japamac for the replies and information. I tried to disable the bad processor using the Open Firmware method, but I couldn't get the machine to boot into OF. That may because I have issues with the keyboard not working, even on a normal boot, until I unplug and re-plug the USB connector after the sign-in screen appears (could be I should plug it into the tower, rather than the display).



Anyway, I removed the bad processor and booted with only the one processor in the top slot. So far the computer seems to be running normally (if slowly) and I've been able to sleep it and wake it. The fans, however, are running at full speed. I was hoping that without the bad processor, the fans would behave normally (ASD says that the good processor does not need calibration).



Do you know if there's a way to run with only one processor installed AND have the fans behave normally. The constant noise sets me on edge.



Thanks,



-Aron

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Oct 20, 2018 1:09 PM in response to japamac

japamac - thanks for the reply, and your continued interest in this discussion. Actually, we had a power failure last night (winter storms), and this morning the fans are better - still running fast, but not at full speed.



I had understood that I needed ASD 2.5.7, and that 2.5.8 would not work on my computer (a 2003 PowerMac G5 2.0 GHz dual processor running OS X 10.5.8). Did I have the wrong information about this?





-Aron

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Oct 20, 2018 1:09 PM in response to Community User

Thanks japamac & BDAqua. I just downloaded ASD 2.5.8 last night; haven't had a chance to try it yet. I'm hoping that it will recognize that there's only one CPU, and shut the fans down for the missing one. I'll try it later today, and let you know.



-Aron

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Oct 20, 2018 1:09 PM in response to Community User

Well, I tried using ASD 2.5.8. It wouldn't calibrate, giving me the EEPROM checksum error on CPU0. That's strange, as I've got the CPU that was testing okay in CPU0 slot, and no CPU in CPU1. I also notice that it gives me less information about the CPU when I choose the Hardware Information menu - it doesn't give me serial numbers, and lists the top processor speed as 1152 MHz, when it should be 2000.



I'm hoping this is a combination of having only one processor and something strange with ASD 2.5.8 and my machine. Otherwise I'm facing the issue of the second CPU going bad in a few days - maybe the logic board is destroying CPU0?



Anyway, I'm expecting a replacement CPU tomorrow. Perhaps with two in there, things will work.





-Aron

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PowerMac G5 with fan problems. Is my diagnosis correct?

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