No you forgot one the hard drive. If your getting any odd sounds coming from them that would indicate a bad hard drive. You should be able to change around power supplies between the computers.
I agree with you on logic board.
Well I wanted to assume it was the hard drive too but I have another hard drive i'll have to test to make sure but I can't see the hard drive to be causing the freezing and kernal panicks. At this point I'm leaning towards the processors for Machine 1. They might need to be reseated and need new thermal paste.
A bad hard drive can cause the computer to freeze up. Here's a link you can take a look at with sounds that a bad hard drive will make.
Myself I wouldn't be to concerned about thermal paste unless you have clear evidence that it is causing a problem, perhaps like overheating. But high temps are more likely caused by dust build up in the fans.
Your in a good position where you have two G5's. Between the both of them you should have enough hardware to swap around to get one of them running. Rather than purchasing a power supply or hard drive etc. only to find it wasn't what was needed.
well the cpus could be overheating causing the kernel panicks and freezing and need to be reseated. The hdd could be a likely verdict as well for the freezing but the cpus would also be a contributer I would believe. A lot of people have had to reseat their processors so doing so would most likely fix the problem. I'll give the other hdd a shot with a fresh install of leopard and see what happens. But if that doesn't fix it, I'm going to have to check the power supply voltages and if they are fine then it's most likely the logic board or cpus.
I can confirm there is no dust in the fans, the computers have been cleaned out but I think both computers may be suffering from the same problem as it seems to pretty common in these g5s.
I tried swapping hard drives, Machine #1 still freezes after a certain amount of time. I'm now thinking it's definitely the processors. Sometimes it struggles booting though. As it doesn't chime sometime when trying to boot but then never get a video signal.
As for machine #2 I still get one red led behind the liquid cooler and other times a second red led an inch or two above the other one.
I'm gonna assume at this point both machines may be suffering from the same problem.
I had a simillar problem when refurbing a G5 2.7 dual. I renovated the LCS, after re-assemby I also got the red light behind the LCS, I solved the problem by removing and re-seating the processors. If you do remove them, it would be smart to check for leaks or white crystalisation around the block, if you find crystals you will need to change the O-rings and probably drain and refill the LCS. If there is no crystalisation replace the thermal paste with Artic MX4, you will also need to re-calibrate the processors with ASD 2.5.8.