My 2009 Mac Pro keeps shutting down - help!

[rondocap]

I have a 2009 Mac Pro, 16 gigs of OWC ram, SSD hard drive for my boot drive and latest version of Lion. I also have an upgraded nVidia graphics card.

A few months ago, it did the same thing, here are the symptoms:

After a few minutes of use, system just shuts down. Power flickers on and off for a while, and it turns on and off. After unplugging, it will work again for a few minutes and then shutdown.

I changed the outlet to where it was plugged to, and that seemed to fix the problem for a couple of months with no issues. Then after a really hot week, the problem came back again and it keeps shutting down.

I already tried running it without the video card, no use. Is it the PSU? Why did it work after I switched outlets the last time?

 

[brand]

Are you not using a good quality UPS?

 

[Macsonic]

Hi Rondocap. Might be possible it's your PSU but nothing definite. To isolate, can you try using a different UPS and see if your Mac Pro still shuts down. And if you have a second Mac machine, try using it also on the UPS to check it it's the power supply or the UPS.

 

[rondocap]

I have another mac connected to my power surge protector, no issues.

Is there a way I can isolate it and see if it really is the PSU? Are there exact symptoms or clicking noises I should be looking for?

Is it hard to switch out the PSU myself?

 

[brand]

Is there a way I can isolate it and see if it really is the PSU? Are there exact symptoms or clicking noises I should be looking for?

What are all of your system temps prior to the shutdown?
Do the all fans freely spin when no power is applied?
Do the all fans spin when power is applied?
Are there any swollen capacitors on the logic board or daughter boards?
Have you tried installing your original RAM and graphics card to narrow theses components out? That is the first thing Apple would do.

Is it hard to switch out the PSU myself?

Not real sure how you expect us to answer that without knowing your technical abilities. Given that you are having to ask I would say that yes it is hard.

 

[wonderspark]

I have another mac connected to my power surge protector, no issues.

Is there a way I can isolate it and see if it really is the PSU? Are there exact symptoms or clicking noises I should be looking for?

Is it hard to switch out the PSU myself?

A surge protector isn't a UPS (uninterruptible power supply) which is what every desktop computer should use, in my opinion.

 

[brand]

A surge protector isn't a UPS (uninterruptible power supply) which is what every desktop computer should use, in my opinion.

I completely agree. I don't see how people can carelessly use something that is often times nothing more than a multi-outlet extension cord for their $2500+ investment.

Additionally, I don't remember the specifics off of the top of my head but the cheaper priced ($50 - $300) UPS units actually harm the Mac Pro. There have been several threads here about it over the past years.