G5 Dual won't start, which component is it?

D

DUNNO

Registered
Hello everyone,

I've got a 2nd generation G5 Mac, Dual 2 Ghz, 10.4.11 that won't start anymore. It will power on there is a chime and the fans will get louder and louder but I don't get a picture, the monitors just say no signal and thats it. I can't try to startup in singlemode etc. because the usb devices don't get power so no key commands. I had some freezes with this comp here and there before but not really often (I heard this gen of g5s has these quite regularly?).

Actually after having unplugged it for some time I may get it to start once or twice. But after some time it will crash (Black Screen telling me to shutdown) again and afterwards won't start anymore.

During such a lucky start I reset the P and NV Ram I reset the SMU on the Logic Board. No Luck.

I have unplugged everything apart from the keyboard, removed all pci cards except the graphic card, and tinkered with my 6 Ram pieces a bit. I found out one of them does not work anymore so i used two pieces i know that work.

The monitors are okay, the hard drives too, i just put them into a g5 2,7Ghz and they work just fine.

So what's left, Logic Board? Graphics card? PSU? How can I find out?

The latter two I could replace probably, but if its the former I will have to give up on this comp.

Anyone any idea?

Thank you

Dunno
 
The black screen telling you to shut down is the sign of a kernel panic. So if you are getting the startup chime, that's telling you (in theory) that the system has past the hardware (aka Power On Self Test, or POST). My guess would be one of 2 things. First, take 2 RAM chips out of your 2.7 since those are known to work and place them in the 1,1 and 1,2 slots of your dual 2.0. My main guess is that you have a bad kernel extension left over from one of your PCI cards. What PCI cards did you have in there? The reason I ask is that I have had a boatload of issues with SATA and SCSI PCI cards in the G5 systems. The bulk of which have been with the SATA cards. So here goes....

Plug in a mouse to the front USB port and try to boot up. Does the light on the bottom of the mouse come on? If so, shut down and plug a keyboard in as well.

Try to get the DVD tray open and put your OS disk in. Try to boot up again from the DVD by holding down the "c" key.

Go through the setup process doing an Archive and Install so you don't lose everything. By the way, do you have a backup?

I just suspect you are having trouble with a kernel extension loaded from one of your PCI cards. I know there are easier ways of tracking it down and deleting it. However, I have tried to do that myself with little to no luck. Once I deleted the wrong kernel extension and nothing would work! Oops!

One last thing to try...Pull your hard drives out and try to start up. If all is good with the hardware inside the box, you should get a picture on the monitor indicating there is no operating system (folder with blinking ?) to boot from.

Lastly, I really don't check these boards very often, so feel free to email me at dan.may@mac.com if you would like further advice. Good luck!
 
Happened once to my son's G5. All it was was the PMU (a small black button on the motherboard that needed to be reset--push it in and restart.
 
MyChalupa said:
I just suspect you are having trouble with a kernel extension loaded from one of your PCI cards.

Go through the setup process doing an Archive and Install so you don't lose everything. By the way, do you have a backup?
Click to expand...

Good advice, but I think the archive and install is just unnecessary at will likely die right in the middle leaving them with a fubared system on top of all the issues they are having now. Booting to a installer DVD or better yet an external system is good enough to rule out a bad kext.

Its a good possibility one of the processors has gone south or even the logic board. The best thing you can do right now is unplug hard drives, optical drives, installed PCI cards, external devices, etc..and just basically run with 2 known good RAM chips in correct slots, (one chip at very top of the the eight slots, one at very bottom), PSU, processors, fans, video card and see if the monitor lights. If still the same symptoms, it could be the possibly reseating the processors would correct everything because the normal vibrations of the machine will make the processor pins come out of alignment with logic board after a while. Other than that if these procedures are beyond your scope of ability, than these and further procedures are better left for an Apple Authorized shop to troubleshoot.
 
Wow, thanks a lot guys.

First of all I don't fear data loss. I have a backup and have my original disks running in the 2,7 Ghz now - so far so good.

I tried a few things with the 2 Ghz:

I removed everything including the harddisk put the first two ram from the 2,7 in and tried to start and got the chime. Then I put a freshly installed system disk from my 2,7 into the 2,0 and it started up, everything worked fine, for about two hours. Then the system froze (no black screen) and i had to manually turn it off. After i tried to restart it it started osx but froze again after about 2 minutes. Now it freezes everytime soon after Osx is up.

Was it a mistake to create a system disk in the 2,7 and put it in the 2,0 or is it just another symptom of the same problem?
Tomorrow I will try reseat the cpus and try to install from disk. Are there other things I could try tomorrow? I luckily have some time on my hands then.

@mychalupa
I had a RME Hammerfall 9652 Soundcard and a TC Powercore Card installed. Now that you mention it I remember to have had a few problems with the TC card recently when it would not boot up properly.

@sgilbert
I had already reset the pmu (called it smu in my first post) but thanks nevertheless

@djackmac
How can i test if it is the cpu or the logic board if everything else fails?
 
I have run the Apple Hardware Test. No problems found.

What other diagnostics could I run. I get it to start for a 1-2 hours sometimes after it has been off for some time so I can check a few things there until it freezes again.
 
DUNNO said:
I have run the Apple Hardware Test. No problems found.

What other diagnostics could I run. I get it to start for a 1-2 hours sometimes after it has been off for some time so I can check a few things there until it freezes again.
Click to expand...

Sounds to be heat related so I would loop the AHT for several passes to see if anything fails before it freezes again. But don't be surprised if it doesn't fail.
 
I will do that.
I also thought it might be heat related.
Does this hint to a problem with the cpus, the cooling system or the psu?
 
Well, update.

Before I could start the Testloop the comp froze and there is little hope I get it to work again without leaving it off for a few hours.
 
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