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mark8

macrumors member
Original poster
Nov 29, 2010
77
1
WNY
Yeah I'm still messing with PPC G5 Dual 2.5Ghz(and 2.0).
I rebuilt the LCS on a few of the machines. and did some experimenting with 2.5Ghz processors with 2.0Ghz heatsinks. Ran ASD 2.5.8 on the air cooled G5. and got a Tafs out of range on CPU1. Is cpu1 the top processor on the logic board? I want to reapply heatsink compound on cpu1 and see what happens. That G5's fans were running pretty high. My 2nd question is with the G5 w/2.5Ghz LCS sys. If I remove the air deflector, the fan speed does not ramp up like it should, no red LED on the logic board(it stays @ a ramped up speed, not airplane but up there). Ran ASD on that one and got an intake fan error. Is it an air deflector sensor issue or something else? I tried swapping out the fan, as well as the air deflector and no change. Is there a way to test the sensor? I also ran the stand alone test and Everything passed. Weird right? These machines are so touchy. Any solutions would be helpful.
thanks in advance
 
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Yeah I'm still messing with PPC G5 Dual 2.5Ghz(and 2.0). A die hard or just dumb.
This is the only thing I can help you with.

Your thread is in the PowerPC forum so you will get no condemnation or upgrade suggestions from us, especially from those of us (not me) that own 30+ PowerPC Macs.

I have a G5 Quad, a G5 2.3 Dual Core and one G5 2.7 Dual Processor on the way. There are three PowerBooks in the house and an iBook. There are two PowerPC iMacs of mine at work.

Hopefully someone who knows more about the G5s can help you.
 
I am going through a similar situation. I had a G5 dual 2.5 WC that was leaking. I replaced the 2.5s with 2.0s air cooled but one CPU was bad. The top CPU is CPU0 and the bottom is CPU1. What I did was disabled the second CPU which is CPU1. Make sure the good CPU is in CPU0 slot. Boot into open firmware and type the following .

setenv boot-args cpus=1
reset-all

On reboot, I was able to run the ASD disk and calibrate the fans. It also passed the ASD test as well. I am not sure if the 2.5s are still good. I need to clean them and see if they will work. My bigger problem is that the logic board has a U3 BGA issue. Have you tried resetting the PMU and NVRam reset?
 
"Have you tried resetting the PMU and NVRam reset?"

Thx for the answer on the cpu's. Yeah I did those PMU NVram a couple of times. My guess is the air deflector sensor is bad.

spf2-did you check the pins on the logic board and the cpu, to see if they were bent? also when one cpu has a tafs error, pull that cpu and re-apply thermal paste, then cycle it several times. Then try to do a thermal calibration
 
The pins on the board and cpu were fine when I checked. I actually had to move the bottom CPU to the top then disabled the bottom CPU for it to boot and run properly. I think you are right about the air deflector sensor.
 
so CPUA is the bottom one? It's running 30 Degrees, hotter may have to reapply thermal paste
 
well the air-cooled 2.5 seems to be ok after a thermal cal. Cpu A still runs about 20 degrees hotter(even after re-applying thermal paste).
ok i fixed the sensor on the 2nd G5(LCS sys). The air deflector removal turns the LED's on and the fans ramp up. I did try a second set up(LCS) and still get the intake error. The pumps for both work( bench tested with a 12v power supply) If a try to do a thermal cal i still get the intake fan speed error. I think the rom may be screwed up
 
I don't know anything about the G5 systems, but it's interesting to read about them. Thanks for the update and good luck!
 
well I reinstalled the OS(10.5.8), in the hopes that the Thermal Cal intake error had to do with corrupt files on the HD, after trying yet a 3rd LCS set-up, the cpu intake fan error remains. must be the logic board. I bought this used maybe someone tried and aborted a thermal cal before me and it corrupted it somehow. If there was only a way to flash the rom. any engineers out there that ran into this problem? ha!
 
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