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View Full Version : Power Mac G5 dp 1.8GHz fans @ full speed




kbfr08
Jun 25, 2010, 01:27 PM
My PCI bay fan is running at full speed no matter what. The temperature sensor reads correctly in OS X, so I don't think it's a bad sensor.

Is there any way to set the fan speed manually, say in openfirmware?

It's a 1.8 DP June '04; I've ran ASD 2.5.8 to calibrate and test the mobo, which passed.



max••
Jun 26, 2010, 04:22 PM
you could try this although i have never tried it

bizzle
Jun 26, 2010, 04:42 PM
smcFanControl does not work on PowerPC Macs.

Have you tried resetting Open Firmware? Boot into Open Firmware by holding Option-Command-O-F and type 'reset-nvram' and 'reset-all'.

max••
Jun 26, 2010, 04:44 PM
smcFanControl does not work on PowerPC Macs.

Have you tried resetting Open Firmware? Boot into Open Firmware by holding Option-Command-O-F and type 'reset-nvram' and 'reset-all'.

oh, didn't know that

kbfr08
Jun 26, 2010, 11:27 PM
Yep, i've tried pram resets, nvram resets, everything that I could be reset was reset.

666sheep
Jun 27, 2010, 03:05 AM
Try to disconnect sensor cable and see what happens. If sensor is OK, fan needs to be replaced.

kbfr08
Jun 28, 2010, 10:44 PM
every fan runs at full speed when the sensor cable is disconnected. Anyway, I did a complete rebuild of the G5 and it made no difference either.
I just installed a quiet fan on the FX5200 using a 12VCC pin on one of the ICs to keep the card from overheating. The large fan is now unplugged until I find a solution.

OrangeSVTguy
Jul 8, 2010, 02:58 PM
Are you running it without the clear air baffle? Try sticking a piece of paper folded up in the far right slot. It's at the bottom right hand corner when you remove the side door. There's a little sensor there that will tell the fans to ramp up if the air baffle is not present. It could also be defective...

666sheep
Jul 8, 2010, 03:05 PM
If air deflector sensor would be defective, red diode at front of logic board should light.

toolbox
Jul 9, 2010, 07:04 AM
Exactly, the CPUs' haven't been removed? Some of them need re calibrating if there removed from the logic board.

OrangeSVTguy
Jul 9, 2010, 11:44 AM
Exactly, the CPUs' haven't been removed? Some of them need re calibrating if there removed from the logic board.

Good point! OP, Reboot the G5 with the ASD disc and then run a thermal calibration.

666sheep
Jul 9, 2010, 01:19 PM
I've ran ASD 2.5.8 to calibrate and test the mobo, which passed.

Recalibration was done by OP. Besides, as long as CPUs were removed but not swapped between sockets (or replaced), recalibration shouldn't be required.

toolbox
Jul 9, 2010, 07:40 PM
I have also had a faulty Thermister also. That was making the fans roar constantly. I replaced that and it settled down