Late 2007 Mac Pro, what the heck?!?

[fxrtst]

I have a late 2007 Mac Pro 8 core 3.0ghx, system with 16 gigs of Ram. Two hd, one with OSX 10.5.2 and one with Vista Ultimate x64. I have a mac mouse and keyboard.

I have unpredictable, spontanious reboots. This happen on either OS's. I DO NOT have "reboot on power failure" check marked in the power savings menu. Once this cycle starts it gets worse, until the system just loops non stop at the beginning of the boot sequence, just a clicking can be heard. I have to power button off and unplug to stop it. Then when it reboots it sometimes happens again and other times not. Sometimes I may be moving the mouse or clicking then it just reboots. Or I might try to start a program, and it reboots.

I took it to the 'Genious Bar', this guy told me to make sure its grounded propery on the outlet, that it must be a three prong outlet with a properly connected ground. And to uncheck "reboot on power failure" Which i told him it was not checked. Of course it did not reboot or show any signs of a problem while I was there. I came home and moved the computer to a new outlet. It ran fine (as it did in the store) for about a week, then the problem came back. I had not changed anything.

I ran a harware test and everything came back fine, so no problem with bad RAM etc. Is it possible to have a bad power supply, would this be a symptom? Or possibly a bad power cord? And why would my computer reboot instead of power off, if I have unchecked "reboot on power failure" ?!?

Anyone experiencing anything like this? Any ideas, things to try? The computer is unusable at this point and has rebooted while using programs, that the programs will not longer start and have to be reinstalled. Help!! Thanks in advance.

Will

 

[Sun Baked]

No beeps from you line conditioning UPS?

Did it work fine on an extended test at the Apple Store?

 

[fxrtst]

This is straight into the wall, no UPS. Mac store did not keep my computer to perform extended hardware test. Sent me home, he was sure it was my recepticle.

 

[surflordca]

You plugged the computer into a new outlet but is that outlet on the same fuse in the fuse box of the house? You might be getting brown outs from the hydro. I would strongly suggest a APC unit.

 

[fxrtst]

I'll go out today and get a UPS, APC unit and see if it makes a difference. Again I am stumped by the reboot if I have "reboot after power failure turned off"

 

[tuxtpenguin]

The machine may not be turning itself off during the brownout so it will restart. Of course, this is only theory.

 

[Sun Baked]

I'll go out today and get a UPS, APC unit and see if it makes a difference. Again I am stumped by the reboot if I have "reboot after power failure turned off"

Just make sure it is the line conditioning unit with AVR, versus a battery backup.

A member in Florida got the straight battery backup variety, and the low voltage conditions always messed the machine up. The UPS was just useless for his area and rarely worked.

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Moving the machine to a circuit in the house without motors (refrigerator/ac compressors, fans, florescent lights, etc.) sometimes solve the issue also, or simply that the current breaker is overloaded (we are stuffing a lot onto single circuits these days with all the high draw devices and the number of rooms a breaker services.)

 

[dchao]

Just want to add: You will need an UPS at least 1500VA and can handle 850+ watts of power. Otherwise, you will have the wake from sleep surge problem.

 

[fxrtst]

I ran out and got a regulator/back up..1500av and 850 watts. Before I was even able to try it out. I upgraded to 10.5.3 and I, like many have a computer that will not boot, it just hangs on grey apple screen. It looks bad and all the fixes are above my head. I am an old (20 year) windows user and not proficient in the Mac ways. I'd love to boot in to the 'c' drive and fix up the files etc. But I stare blankly at the single user interface or any other modes just trying to get to my files on the Mac HD.

Will

 

[fxrtst]

Well I managed to get everything back to normal. Only to find that I am still having reboots or power interuptions as before. This is all plugged into the new power regulator. So I am thinking that it may be the power supply? A call to Apple?

 

[Sun Baked]

Reset SMC

You can also try ...

To start up in single-user mode:

1. Choose Apple menu > Restart, or press the power button if the computer is turned off.

2. Press Command-S as the computer starts up.

The computer screen is black with standard white text. You can now run the UNIX commands that you want.

Follow the directions on screen for fsck ... if it fixes something, run fsck again until it comes back clean, or stops making the repairs, or cannot make them.

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Mac OS X: Starting up in Safe Mode This is for the times when some application/hw driver is causing problems.

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The 3rd party USB kb, hub, ect. can cause problems so keeping those unplugged during this can help. Checking the pins on the video cable, back of video card, the keyboard cable, USB port ect to look for bent pins can also help.

If you have Applecare, running the HW test is another option.

If the machine can stay stable long enough and you have an Apple ID you can try using the Apple Service Tech hardware diagnostic DVDs ...

http://www.info.apple.com/discimages/

 

[fxrtst]

I have reset all of the above. I will have to wait and see if I get the reboots, as they happen spontanous. Thanks so much for all the info!

Will