Quad Issues

bunnspecial

macrumors 604
Original poster
May 3, 2014
6,718
3,271
Kentucky
I mentioned this last week, but I pulled the processor cards on my Quad late last week to repaste the CPUs.

Since then, I have not been able to get it to boot.

Reading the LEDs on the logic board, and following the service manual, it looks like everything more or less proceeds normally within the first few seconds of power-up. There are initially no lights on, and LED 7 flashes momentarily(as per the service manual, this is normal). A few seconds later, LED 2, indicating CPU overtemperature, will come on and stay on.

I've pulled the cards again and verified that they are in solid contact with the water blocks then(again) cleaned and repasted both the blocks and the CPU dies. I have the hex-head spring loaded screws snug, so the contact between the blocks and the CPU should be good.

The LCS has no leaks and I can hear the pump running when the system is powered on. All fans are also running. I do have the air deflector in place when all of this happens.

Does anyone have any thoughts on what could be going on?
 

Goftrey

macrumors 68000
May 20, 2011
1,844
70
Wales, UK
Grab a magnifying glass and take a look at the pins on both the daughter cards & the motherboard itself. They are extremely fragile and it's very easy to bend even just one of them ever so slightly out of place.
 

RedCroissant

Suspended
Aug 13, 2011
2,262
94
I could be crazy here, but isn't it a necessity to recalibrate the system after upgrading/modifying the CPUs? I know that you simply replaced the CPUs but that might have been enough to cause issues.
 

Altemose

macrumors G3
Mar 26, 2013
9,089
444
Elkton, Maryland
@RedCroissant Yes. Whenever the CPUs are removed from a G5 then the cooling system should be re-calibrated. That being said, a G5 should run without calibration but with the fans at full blast. The fact that bunnspecial's G5 is not booting at all indicates an underlying issue.
 

bunnspecial

macrumors 604
Original poster
May 3, 2014
6,718
3,271
Kentucky
On a whim, I bought a complete LCS/CPU assembly from Ebay.

It dropped right in, and I'm happy to report that I'm typing this message from the Quad now.

I haven't run thermal calibration yet, but the fans are running at what I would consider "normal" speeds and temps look good. I might run it tomorrow, but for the time being I'm happy.