MacPro goes dark - stuck in limbo

[muaythai]

My wife's MacPro was running just fine until our power went out yesterday. After the power came back, A strange problem appeared. The machine powers up, gets through the logo screen, gets through the login, gets to the desktop, but then suddenly the screen goes black. The screen is actually on, i.e. it's illuminated but the pixels are black. The CPU is also on- I can play MP3's by pusing the play button on the keyboard. I just... can't see anything.

I've tried the following:

• Zapping the PRAM
• Resetting the SMU
• Calling Applecare three times with no real solution, other than take it to an Applestore, which we don't have in the country we're living in
• Going into recovery mode and reinstalling Lion
• Going into recovery mode and restoring from a Time Machine backup

Restoring from the Time Machine backup worked this morning, and I though the weird problem was solved. YES! But no, the computer is suddenly going black again, after approx. 8 hours of working completely fine.

I'm now here at the mighty MacRumors forums, crossing my fingers that someone knows what's going on! I'm down to try anything- please help. Thank you!

 

[Neodym]

1. Try to put in another graphic card to check whether the current one may be damaged. There are some PC cards you can use without flashing or installing special drivers if you are running 10.6.8 or later. As Mac cards are usually not cutting edge, maybe a PC-using friend has one lying around he can borrow you for testing purposes.

2. In connection with UPS's and Mac I recall that some people recommended against some special UPS's as they could damage the MacPro's PSU during a brown- or blackout due to their operational "behaviour". Therefore chances are that the PSU in your MacPro has been damaged during the blackout you experienced. It may work, but when the load gets too high, the voltage collapses.

You could try to reduce the load on the machine by removing hard drives, PCIe cards, memory sticks etc. and unplug any externally connected devices that are usually powered by the Mac. If the graphic card is not the standard, passively cooled Apple card, try to put that back in. Try to run the machine with the reduced load and see what happens.

However - if the PSU is really damaged, you may need to have a technician check the Mac. If there is no AppleStore in your country, there should be authorized repair centers you could contact. See this page to find one near to you.

You could also try to run the Apple Hardware Test, but I'm not sure whether it could recognize a potentially damaged PSU. At least it may find other potential problem sources - if your Mac runs long enough in the first place (see above how to reduce current load in your machine).

 

[Puevlo]

Safe boot. It's only affecting after logging in so safe boot will disable whatever opens at login.

 

[DanielCoffey]

If in the future you are looking for a UPS, you will want one of the Pure Sine Wave ones such as the APC Smart-UPS range. I use the APC SMT1000I model.

 

[muaythai]

Thanks for the replies everyone. My wife finally got a really good Applecare person on the phone (had to go up a few tiers) and like Puevlo mentioned, he had her boot up in safe mode. Then he had her revert all the way back to Leopard- the original discs the machine came with. We're lucky we had those original discs, plus our Snow Leopard DVD. Shame about Lion being download only- really really bad idea Apple! Anyway, we made a disk image of that before we left the US ;-)

We're now just finishing downloading the first update of Lion. After that's installed, he said to restore form time machine. Fingers crossed.

Thanks guys!

 

[DanielCoffey]

So it appears it was a software issue then? That is lucky.

 

[ratfink]

If this turns out to be a software issue it would be great to hear. I have a 2008 Mac Pro that is having a very similar problem. I suffered a power failure while using a crappy UPS. After that the machine started randomly powering off. I reinserted my old GPU and things were fine for awhile. Now my display just goes black occasionally, and the computer keeps running.

Please let us know if the reinstall fixes your problem.