Mac Pro cuts out as soon as you turn it on.

[BearSteve]

Hi there,
I have a tricky question that I hope someone can help me with. I have a Mac Pro Early 2008 and has suddenly been cutting out as soon as you try to press the power button.

I have tested all the RAM and nothing has changed however I did discover that after a few seconds of cutting out OTA and OTB flash once on the 8 diagnostic LED's.

Thinking it might have been the system battery, I replaced it and now it is trying to start itself every 10 seconds or so but instantly cutting out.

Has anyone heard of something like this happening?
Many thanks.

 

[louishen]

Have you reset the power management?

Resetting PowerBook and iBook Power Management Unit (PMU)

 

[harryb2448]

And this is on a Mac Pro not a MacBook Pro?

From your description sounds like a faulty power supply.

 

[BearSteve]

Thanks for the response guys,
I have reset the PMU and the issue hasn't changed. It is a Early 2008 Mac Pro tower with 32GB RAM which I've checked separately. Might need a visit to the genius bar

I suspected a faulty power supply but wouldn't that deem no power at all? The "click" sound when you first turn it on sounds again when the power is cut 1/2 a second later.

 

[minamina]

Same issue here..

Hi Bearsteve, i have exactly the same symptomes on my macpro early 2008. Did you find a solution? I thought it was disk errors due to stoping brutally when starting, but no.. then i thought it was electricity network at my place, i bought an inverter, but the problem is still there. i have this pb with my macpro since a year now (comes and goes randomly) If you have any clue, please let me know! i'll send you flowers...