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Jonathan Renouf1 Level 1 Level 1 (15 points)
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)
  • BDAqua Level 10 Level 10 (119,090 points)
    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
  • Jonathan Renouf1 Level 1 Level 1 (15 points)
    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
  • BDAqua Level 10 Level 10 (119,090 points)
    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/
  • Jonathan Renouf1 Level 1 Level 1 (15 points)
    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
  • BDAqua Level 10 Level 10 (119,090 points)
    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?
  • Jonathan Renouf1 Level 1 Level 1 (15 points)
    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
  • Jonathan Renouf1 Level 1 Level 1 (15 points)
    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
  • BDAqua Level 10 Level 10 (119,090 points)
    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.
  • Jonathan Renouf1 Level 1 Level 1 (15 points)
    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
  • BDAqua Level 10 Level 10 (119,090 points)
    It's sounding more & more like a Hardware issue.
  • Nick Dacek Level 1 Level 1 (5 points)
    Try changing ram/omitting ram..but id agree could be logic board related.
  • Hubz Level 1 Level 1 (0 points)
    g5 dual 2.5 only boots when plastic cover is off? Same issues. smu reset did nothing.

    any ideas?
  • Jonathan Renouf1 Level 1 Level 1 (15 points)
    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
  • gbotis Level 1 Level 1 (0 points)
    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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