6 Replies Latest reply: Nov 15, 2012 7:18 AM by Skorpan
imgarrett Level 1 Level 1 (0 points)

I have two G5's with different problems. I think I have it narrowed down but need more inisght and support.


Machine 1 Boots, randomly freezes, sometimes throws a kernal panic. Then after freeze refuses to boot, no chime, no front panel led, no video signal. It just sounds idle, fans run, that's it.


Machine 2

No video output, chimes on turn on, sounds like it's booting up. Get 1 red led on the logic board but not sure what it means. I can't tell as it's right behind the liquid cooler closest to the bottom row of ram slots.


It can't be the pram battery as I tested both batteries for both machines on a multimeter and both pull the amount of voltage the battery is rated for.

Can't be the graphics cards as I swapped both between machines and both graphics cards work. Ram seems fine I have swapped it between both machines and ran a mem test.


The only thing left is either the PSU is on its way out, the logic board, or the cpu's need new thermal paste and to be reseated.

  • 1. Re: Two G5, Two Problems
    Jacumba Level 4 Level 4 (2,325 points)

    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.

  • 2. Re: Two G5, Two Problems
    imgarrett Level 1 Level 1 (0 points)

    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.

  • 3. Re: Two G5, Two Problems
    Jacumba Level 4 Level 4 (2,325 points)

    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.

  • 4. Re: Two G5, Two Problems
    imgarrett Level 1 Level 1 (0 points)

    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.

  • 5. Re: Two G5, Two Problems
    imgarrett Level 1 Level 1 (0 points)

    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.

  • 6. Re: Two G5, Two Problems
    Skorpan Level 2 Level 2 (375 points)

    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.