Mac Pro (2008) won't boot consistently. Getting repeating startup chime.

[iamkarlp]

I have a Mac Pro which seems to have become sick. It normally won't boot, and when it does it will lock up after an hour or two and then proceed not to boot for awhile.

It doesn't seem to be a heat issue.

The machine boots up, gives a startup chime, then waits 3 seconds, and chimes again. It does this repeatedly - chime - 3 seconds - chime - 3 seconds - etc, until you hold the power button to kill it.

Any insight appreciated.

Karl P

 

[666sheep]

There is only 2 potential reasons:
– bad PCIe card (most likely graphics card)
– bad logic board
Remove graphics card and try to boot. If you have any other PCIe cards, remove one by one and test.

 

[OS6-OSX]

Also search 1. Zapping the Pram 2. Resetting the SMC

 

[iamkarlp]

GFX looks spot on.

I didn't have another Mountain Lion compatible video card laying around, so I threw in a low-end (windows) workstation Nvidia card figuring that it would at least make the noises stop if that was the problem.

Imaging my surprise when it cleanly booted right up.

I have rebooted it a few times and all seems well.

A new ATI will be inbound shortly.

Karl P

 

[dunderheid]

Boot loop workaround

If it's any help, my 2010 Mac Pro has booting issues and goes into a "boot loop" if my monitors are switched on when I boot. My workaround for this is to boot the Mac and then power up my screens. So I guess that points to a PCI Graphics card problem, which I haven't investigated any further as I have a working solution.

Mac Pro 3.33 6-core, ATI Radeon HD 5870, 2 x Hanns-G 27" monitors