G5 won't boot up

Question

G5 won't boot up

Can anyone help me solve the following problem?

My G5 currently won't boot up. When I press the "on" button, I get the Apple "boing", but the screen remains dead.
If I leave the computer on anyway, then within five minutes the fan starts to rev up into overdrive.
I've tried booting in "safe" mode, and I've also tried booting using my back up firewire drive. No response.
Incidentally, I've removed all other devices so only the keyboard and firewire drive are plugged in.
I can't boot using the installation DVD because I can't open the CD/DVD tray.

I'm running Tiger.

The problem has developed over the course of the day. On occasion earlier today I was able to boot using the FW drive. And once I even booted up from the main hard drive using safe mode. When that happened I ran Repair Disk from disk utility, but there was nothing that needed repairing.

So, is the hard drive the problem? Or is it a software issue?

And most important, are there any other things I can do to bring the computer back to life?

Jonathan

Power Mac G5, Mac OS X (10.4.11)

Posted on Nov 15, 2009 10:23 AM

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Answer 1

BDAqua

Level 10

238,979 points

Nov 15, 2009 10:59 AM in response to Jonathan Renouf1

Hi Jonathan,

I can't boot using the installation DVD because I can't open the CD/DVD tray.

Hold the Mouse button down while booting should open the tray. If you hold the Option key also you may get the startup manager to choose the Install Disc to boot from.

How to reset the SMU on a Power Mac G5 (Late 2004) or Power Mac G5 (Late 2005) ...

http://support.apple.com/kb/HT1436

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Answer 2

Nov 15, 2009 11:52 AM in response to BDAqua

Oh dear.

I tried restarting holding the mouse down, the door didn't open.
So I tried resetting the SMU (following the link in previous post). Pressed what looked like the reset button, but if it was then it's had a much worse effect. When I plug the computer back on the blue "on" light comes on, but nothing happens at all; disks don't spin, silence. And the power button no longer works. Looking at the diagram showing the SMU reset button in more detail it looks like there's another reset button nearby, and if so, this is the one I pressed. What on earth does it do?

Jonathan

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Answer 3

BDAqua

Level 10

238,979 points

Nov 15, 2009 12:05 PM in response to Jonathan Renouf1

Earlier G3, G4, G5 models...

http://support.apple.com/kb/HT1939

Might be time to replace the PRAM Battery, 4 years is close to their lifespan...

See which one your G5 has...

http://eshop.macsales.com/item/Newer%20Technology/CR2032/

http://eshop.macsales.com/item/Newer%20Technology/BAA36VPRAM/

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Answer 4

Nov 15, 2009 12:14 PM in response to BDAqua

Thanks for your help, very much appreciated. I just took the battery out and then put it back in. It had an effect; the computer did at least try and start up. But then I got a grey screen telling me "You need to restart your computer". Which is one of the errors I was getting earlier in the day.
Is it still likely to be the PRAM battery?
Jonathan

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Answer 5

BDAqua

Level 10

238,979 points

Nov 15, 2009 12:28 PM in response to Jonathan Renouf1

PRAM battery can have very strange effects, just the other day somebody couldn't start a G5, replaced the battery and it started up, others haven't always helped though.

Does it try to boot from the Install Disc now?

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Answer 6

Nov 15, 2009 12:56 PM in response to BDAqua

It's died again. For a short while it booted up off the hard drive just like in the good old days, but then it froze and the only way to shut it down was to depower. And now it's back to not starting up. I'll replace the battery and pray...
Jonathan

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Answer 7

Nov 17, 2009 2:05 PM in response to Jonathan Renouf1

Unfortunately the replacement PRAM battery has made no difference. Things are going from bad to worse. I managed to boot the computer up once today, but when I tried to shut it down the screen suddenly went into a stream of repeated text, with the words "unexplained kernel panic" coming round again and again. I've also noticed that when it fails to start up, the little "on" light does a rapid double blink, rather than being on permanently.
I can't get the G5 to boot from an external drive, and I can't open the optical drive to load a DVD.
Is this a hardware or a software issue?
Thanks
Jonathan

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Answer 8

BDAqua

Level 10

238,979 points

Nov 17, 2009 5:46 PM in response to Jonathan Renouf1

I can't open the optical drive to load a DVD...

Hold the Mouse button & the Option key down at bootup to get the door to open.

Is this a hardware or a software issue?

Can't be certain yet, because a really messed up HD can cause this SW wise, might pull the HD & see if it boots off an external FW drive.

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Answer 9

Nov 18, 2009 12:38 AM in response to BDAqua

I've tried holding down the option key/mouse, the optical drive stays resolutely shut. I'll take out the HD tonight and try and boot from the backup. If this fails to work, does it suggest a motherboard issue?
Thanks

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Answer 10

BDAqua

Level 10

238,979 points

Nov 18, 2009 11:43 AM in response to Jonathan Renouf1

It's sounding more & more like a Hardware issue. 😟

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Answer 11

Nov 19, 2009 10:56 PM in response to BDAqua

Try changing ram/omitting ram..but id agree could be logic board related.

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Answer 12

Hubz

Level 1

8 points

Nov 20, 2009 8:10 AM in response to Jonathan Renouf1

g5 dual 2.5 only boots when plastic cover is off? Same issues. smu reset did nothing.

any ideas?

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Answer 13

Nov 24, 2009 6:12 AM in response to BDAqua

Further news: I managed to get the G5 to boot up and run for a few hours on Saturday, so I got all the important data I needed to off it. Then it froze again. And now it won't boot at all; I don't even get the start up chime. Instead the "on" light repeatedly blinks twice. I've rejigged all the RAM around (I had 8GB in 8x1GB units), trying different "pairs" in different slots, but no joy. It powers up, the hard drive spins, but nothing more happens.
I'm considering switching the HD from my old G4 into the G5 to see if that'll work, but I don't have much hope. It feels a more fundamental issue to do with the way memory is read and/or the logic board. What's the advice?
Thanks
Jonathan

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Answer 14

gbotis

Level 1

0 points

Nov 24, 2009 8:48 AM in response to Jonathan Renouf1

same problem with powermac g5 2.5

tried reseting pram and pmu with no luck

keyboard and mouse seem no to respond

seems to be a logic board issue

is it possible to find a replacement?

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Answer 15

Nov 24, 2009 10:19 AM in response to Jonathan Renouf1

I am having the same problem as you. Did you read the kernel panic message? Because I read mine and its says CPU 1 failed and kicked the bucket so maybe thats what happened to yours? To get the CD tray open slide down the silver door in front of it and push a paper clip into the small hole in the bottom left part of the cd tray and then once it pops open pull it all the way out.

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