Q: My Mac Pro spontaneously restarts

Great. Upgraded to Snow Leopard two weeks ago and ewas keeping my fingers crossed. No spontaneous restarts till today!! **** **** ****.

Great post. Today I brought my machine to the local Apple store and it ran perfect in the store. Multiple restarts, stress tests, everything to reproduce the reboot issue, to no avail. Remembering the UPS post, I started thinking about where my machine was plugged in. I had it plugged into a surge protector with bunch of other things. I switched to straight into a power outlet and now I have not had the issue since.

I lam in SoCal and it has pretty unstable power grid during the su mer time. It is likely that my issue is related to that. In the log the reboot usually kHz pens in the evenings and that is when most people are using the grid.

I will keep you guys posted.

/Christian

I just took in a 2008 3.0Ghz mac pro that would restart on its own, or just moving mouse/opening folders.

I've isolated it that nothing else connected and running 10.5.8.

It has been on a good power source (SmartUPS 1500 series) so that was not an issue.

It has the X1900XT Radeon card that was under recall (now no longer covered).

I am going to isolate the ram, and boot from a clean, test OS (10.6.8.v1.1) and see it will run long enough to verify drives. Then I will remove drives. I might have an 8800 nVidia, so I can isolate graphics.

My guess is power supply, logicboard and or grfx card. However, Console logs show no crash log which is odd.

Since it is out of Applecare, the most $$$ is the logicboard and labor.

Will anyone please share more details if a resolution was found (or by Apple repair as in what store replaced to remedy?). Thanks!

It may also be CPU overheating, happened to me a few times, when I downloaded BONIC and it ran automatically while I was watching a video. That **** thing was so greedy and was set by default to use 85% of my CPU, my computer kept restarting until I figured out it was the software.

well I think mine is cured !!

Mac Pro early 2008, running 10.5.8 Leopard

I did 3 things:

1. reset the System Management Controller (SMC) by disconnecting the power cord for a minute or so

2. zap the PRAM, hold down the Command, Option, P, and R keys, at start up, and wait until you hear the startup sound for a second time

3. set the Energy Saver utility to defaults (I have since changed the settings)

it's been two weeks now and no problems

The reality is the following: nobody knows nothing regarding a solution, that is not the exchange of logic board. Apple Computer doesn't accept that is a serial problem to give us a recall , I've reading many people saying a lot  of ******** and nobody gives the true solution, that until now is to exchange logic board . I want a solution that no envolves exchange of logic board .

PS: I have 8 MacPros early 2008 and have exchanged 3 logic boards and have others with the same problem , and I don't want to give more money for an error of  Apple Computer . You know that after long time , Apple accept that graphics adapter of Mac Pro early 2008 had problems and now (after july) is promoting a recall . We have to have this for logic board too . When I talk with them , they say that nobody related this problem before . It's impossible . It's a war and we have to win .

I agree. I've spent more time than necessary in testing known good parts and eliminating everything except: logicboard and processors. The 3.0 ghz quad logicboard is over $499 and each processor is over $1000 if xchanged part with apple. I decided it is cheaper to replace the unit with refurb or newer Macpro due to this model is actually a 2007 model. (labor has exceeded 4 hours with testing ...)

I feel there is some issue with certain boards and processors causing this random restart, and since out of warranty :(

If you know something to solve this problem without exchange the logic board , please tell me . As I have 8  Mac Pros (same model) and I have exchanged 3 logic boards , I've tested every parts of the others and I'm sure that the problem is with logic board (no power supply , no processor , no graphic adapter , no Mac OS  version , no memory , no eletrical issue , no UPS problem - Apple doesn't recomend any UPS) . I have lost much time , doing all the possible tests , with system , without system , with 17 , 20 , 24 and 26  degree Celsius , all possibilities and no solutions , except exchange logic board . 

PS : When one Mac Pro was under garantee , I exchanged a logic board and only two months after , I had to exchange again , because I had the same problem .

> Apple doesn't recomend any UPS

Ballony.

Sorry , "Recommend" -

An uninterruptible power supply, also uninterruptible power source, UPS or battery/flywheel backup, is an electrical apparatus that provides emergency power to a load when the input power source, typically the utility mains, fails .

You can use it to protect your files , not to protect your hardware , and if you read the Apple manual , you won't  see nothing about use UPS  , unless your eletrical source , is not clean and steady .

PS: by chance , I use UPS from 1.5 KWA to 3.75 KWA .   

Did you have a red led near to bluetooth connector .  If not , probably exchanging the power supply will solve your problem . Reading about using a new power supply yesterday , I decided to do a new test with a new power supply , well , I returned to the beginning , I still have a red led , and the same problem , power off suddenly alone . I can run the Apple Service Diagnostic (ASD) 1 ,2 ,3 ,n times with no problems , but suddenly , it's power off alone . Today only the 3 Mac Pros that I exchanged the logic boards , are working fine , the others ... from bad to worse .

Again , I don't want to give more money for an error of  Apple Computer . You know that after long time , Apple accept that graphics adapter of Mac Pro early 2008 had problems and now (after july) is promoting a recall . We have to have this for logic board too . When I talk with them , they say that nobody related this problem before . It's impossible . It's a war and we have to win .

I've been having this issue sporatically for a year or so.  It seems to go along for awhile and all is well, then it starts doing the restate thing.  Last week I ran the Install disk to check for hardware problems, which tested fine.  For that I disconnected everything but the keyboard.  When I got it runing again I realized I hadn't reconnected the firewire external back up drive I have. The moment I pluged it into the computer it restarted.  I have not been able to duplicate it, but I am leaving it disconnected, and every day or 2 reconnecting for a backup.  It has not restarted on it's on since.  So...????

After 24 hours diagnostics we found the source of my spontaneously restarting Mac Pro 3.1 - RAM. After cleaning my case interier and reseting the RAM everything works whole day fine, no problem at all. The service man told me about diagnostic LEDs on the logic board near to RAM slots. They signalized RAM problem

How did you reset the RAM? I have tried resetting PRAM and the power seting (when you unplug it then plug it back in) and nothing seems to work.

My Mac Pro has restarted 8 times in the last 24 hours. I'm at my wits end.

I do not know, the restart was made by staff in apple service. I did not ask them how they reset it