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biquet82
Sep 5, 2012, 12:38 PM
Hello,
My Powermac G5 refuse to start normally: sometimes, it boots perfectly, sometimes it doesn't.

Switch on the G5: fans spin, no chimes, no keyboard, no video, fans accelerate few minutes after...I can just push the power button to switch off the G5.

So, I clean up the G5, disconnected firewire matérials, ram, replace it, disconnected video card, hardrives, I bought new pram battery. Nothing changes.

But, when it starts, the Mac is fully fonctionnal...

Please someone help me ? :(



666sheep
Sep 5, 2012, 04:11 PM
Is it random or on cold boot only?
Did you notice one CPU disappear when it starts and works (if it's DP ofc)?

Either could indicate bad logic board (second one bad CPU too).

Zeke D
Sep 5, 2012, 07:23 PM
I have noticed that g5s don't like soft boots. I disable sleep mode and only shutdown then start up.

biquet82
Sep 6, 2012, 02:00 AM
Thank you for your answers.

Is it random or on cold boot only?
Yes, it's random. There is two days ago, in the evening, it start up 3 times.
Yesterday, it can't boot...the white front led illuminate, but no boots.

Did you notice one CPU disappear when it starts and works (if it's DP ofc)?
I don't know how to do to get this information. Can you explain more about this, please?

I have noticed that g5s don't like soft boots. I disable sleep mode and only shutdown then start up.
Sorry, but what is soft boot?

Another point I used to get, I don't know if it's very important for G5 trouble, I try to explain :o:

For example, I'm running with leopard 10.5.8, and I want to quit/restart.
2 choices: reboot, or shut down.
- With shut down, no problem.
- With reboot option, it will crash on start up, with black screen, no chimes, no video, like the big problem in this subject.
If I want to reboot, I must to shut down, then switch on the G5, after waiting few minutes.

Sorry, I hope someone understand..

666sheep
Sep 6, 2012, 03:51 AM
I don't know how to do to get this information. Can you explain more about this, please?


Under About this Mac -> More info -> Hardware -> Number of processors

I had this exact issue in two G5 2.0 DP, and sometimes when it finally booted one CPU was missing in System Profiler. I assume that one of CPUs was bad in either case because I've tried two different logic boards and it didn't help. Unfotunately I had no working matching CPUs to test it in reverse way.

GermanyChris
Sep 6, 2012, 04:55 AM
If a CPU went out that should trip a red diagnostic LED.

My guess is video card going out.

biquet82
Sep 6, 2012, 05:25 AM
OK, thanks, now it's hard to see "about this mac" section, because it doesn't start everyday .. I need to be lucky :rolleyes:

Just video card, would be a great news !
Do you think I may replace video card first?

I guess this is AGP 8X video card (?), can you suggest a video card or where to find a nice one somewhere? On eBay? It's for music editing.

Zeke D
Sep 6, 2012, 10:46 AM
A soft boot is when you hit restart. A hard boot is when you do shutdown, then press the button to power it back on.

biquet82
Sep 7, 2012, 03:14 PM
Some news from my Powermac G5:

today I was able to copy data with my iBook G4, and firewire cable.
I moved the graphic card (it seems to be ATI Radeon X800XT, but I'm not sure) and reconnected it.
The G5 started and ran all the afternoon.
This evening I shut it down, and when I wanted to start it, no response again ...

Please can you advise me video card I have to buy, because a friend tells me the motherboard's bios can make trouble with some video card.

Thank you.