Acquired new Powermac G5 - High RPM Backside and slots intake fan but normal temps?

[PowerHarryG4]

I just picked up this Powermac G5 2.3 core. The temps seem to be all good but after about 5 minutes of using the computer the backside fan goes up to the full 3000rpm (although when looking at it it doesn't look that fast). I've also noticed that when I take off the clear door while using the computer there is no change in fan speed. Does this sound like a calibration issue or a broken sensor? Cheers.

 

[B S Magnet]

I just picked up this Powermac G5 2.3 core. The temps seem to be all good but after about 5 minutes of using the computer the backside fan goes up to the full 3000rpm (although when looking at it it doesn't look that fast). I've also noticed that when I take off the clear door while using the computer there is no change in fan speed. Does this sound like a calibration issue or a broken sensor? Cheers.

Could be either or, less likely, both.

First up, have a close look at the bottom of the clear door to check if it still has that small protrusion on the bottom which has an opaque label embedded within it. If for whatever reason this bit snapped off, then your problem is the sensor isn’t getting interrupted as it should when the clear door is in place.

Second, I’d run the hardware test for the A1117 (which includes the dual core 2.3). Let that run once and see whether that makes a difference.

 

[PowerHarryG4]

Could be either or, less likely, both.

First up, have a close look at the bottom of the clear door to check if it still has that small protrusion on the bottom which has an opaque label embedded within it. If for whatever reason this bit snapped off, then your problem is the sensor isn’t getting interrupted as it should when the clear door is in place.

Second, I’d run the hardware test for the A1117 (which includes the dual core 2.3). Let that run once and see whether that makes a difference.

Thanks for the reply, I was looking at it again and I think that fan is actually going so high because of the memory controller. It's getting pretty toasty at around 75 degrees. Do you think this could be a build up of dust around the backside of the board?

 

[Certificate of Excellence]

Alot of folks U3 gets that hot especially under load. I'd check that the heatsink clips are on correctly. It couldnt hurt to clean and repaste. I'd still expect temps around 125F when not under load and up to 150Fs when under load.