Mac G5 wont boot

[Tom in HD]

My 5 year old Mac G5 tower wont boot all of a sudden. It wont go past the grey screen with the apple. No wheel spinning. I have tried several things. The hardware checks out good. I tried a different power source as well. My startup disc is a virtually new SATA 500 gig drive. It's only 6 months old. The stuff I am reading on line tells me that it probably isn't the drive that's causing the problem. Is anybody familiar with this problem.
Thanks

[pixel zombie]

try booting from the dvd that came with the machine...

[thevoelk]

Have you reset the PRAM? You mentioned you tried several things, but didn't elaborate. As pixel zombie said, have you, or can you, boot to the install CD or a service CD?

[terryj]

1. If you can boot from the DVD that came with the machine,
then run Disc Utility and verify it sees all drives connected
to the machine. if it does, go to step 2.
if it doesn't see the new HD, then power down the machine,
and check the jumper settings and or cable connections.

2. Then, run disc utility and repair permissions on the new SATA
HD you installed.

3. Quit Disc utility, and open System Prefences--> Startup Disc.
Select the disc with the valid bootable OS X install,
so if it is your new 500GB drive, select that. If it fails to find
a valid bootable OS X install, then go re-install the OS
from the OSX Boot DVD.

[tomlee59]

My 5 year old Mac G5 tower wont boot all of a sudden. It wont go past the grey screen with the apple. No wheel spinning. I have tried several things. The hardware checks out good. I tried a different power source as well. My startup disc is a virtually new SATA 500 gig drive. It's only 6 months old. The stuff I am reading on line tells me that it probably isn't the drive that's causing the problem. Is anybody familiar with this problem.
Thanks

1) Try booting from the DVD first, as others have said. Even if your startup HD is new, it doesn't necessarily mean that it's healthy. If you are able to boot from the DVD, then see if Disk Utility can do something with your HD. And yes, zap PRAM and all those good things. They won't hurt, and might help (although the probability is not high).

It's also not a bad idea to reseat all connectors, memory modules, etc. And if you notice a lot of dust when you open it up, clean that out, too.

2) The G5 apparently has a congenital weakness -- the high internal temperatures cook many of the electrolytic capacitors over time. We've recently been seeing a rash of G5 failures at our school, and are currently trying to negotiate out-of-warranty repairs with Apple (no luck, so far). These capacitors filter the power supply, smoothing out transients. With damaged caps, the voltage fluctuates, causing crashes, failure to boot, unstable operation, etc. If you experienced a mysterious increase in instability somewhat prior to this latest problem, the probability of bad caps being your problem increases markedly.

Good luck! I hope it turns out to be something simple.