Mac Pro randomly shutting down

[GoKyu]

Hey all, I have a 2008 2.8Ghz octo-core Mac Pro which has been nothing short of perfect pretty much since I got it.

Recently (about a week ago), I reinstalled Lion from scratch to get rid of all the cruft/excess programs I don't use anymore. So I'm working with a pretty clean system at this point.

But as of maybe 2 or 3 days ago, the computer would just shut off - not reboot, but turn off, and I would find this out because the screen would suddenly say "No Signal". Yeah. I have the setting "Restart automatically if the computer freezes" set, and that doesn't work either.

Whenever I would hit the power button to turn it back on, it would come on for maybe 2 seconds, then shut down again. I tried removing the side panel and powering on again, and most of the time that seems to work - seems like maybe something's overheating, but I can't imagine why it wouldn't have been doing that for the past 2 or more years if that's true.

It seems pretty random as to when it decides to shut down - one shutdown happened as I was loading photostream in iPhoto, another time I was just reading a website and I had iTunes playing.

I have an iStat screenshot of my temps right after a shutdown, let me know if there's anything else that may help figure this out. I've never had anything like this happen before.

Thanks for any and all help!

 

[ashman70]

I just compared my iStats menu to yours, I have the same machine as you, and it appears that the amps on your CPU1 are about seven amps higher then mine which is resting around 13 amps, yours shows 20. Could be nothing or it could be that your power supply is going. Everything else in your iStats menu looked the same as mine. You can get power supplies new and used online, I don't think its a big deal to replace it yourself, but I've never done it.

 

[GoKyu]

Thanks for the info - I regularly run a LOT of software at once (I have 14 gigs of memory, and I typically only have 3-5 gigs "free" at any time...but again, this has been going on for YEARS now...)

I have the side panel off right now, and here's an updated iStat (this is since my last crash, just prior to posting my first message...)

 

[ashman70]

See now its showing just over 8 amps for CPU1, now I don't know if that is normal for the system having just booted, my system has been running for 6 days and I am around 13 amps. If your power supply is inconsistently supplying power to your Mac, then that may explain the random shutdowns.

 

[GoKyu]

I think I found another big clue today.

I have all the RAM slots on both riser cards filled, but the bottom card has a red light next to one of the chips. I'm still using the computer at the moment, so I went to check how much RAM I actually have.

It dropped from 14 gigs all the way down to SIX. I hope I can just replace that one chip and that will allow the other chips to resume working...

Time to check prices with OWC (or if it's an OWC chip, take advantage of my lifetime warranty...my luck it might be those crappy Hynix chips from Apple...)

 

[ashman70]

You might have bad riser card, have you tried reseating it?

 

[CaptainChunk]

Could be a bad riser card (try reseating, as mentioned before), but it could also be one or more faulty RAM modules.

With 14GB of RAM installed and all slots filled, I'm guessing you're running six 2GB modules and two 1GB modules. Are you only getting a red light on one module? You lost 8GB of RAM somehow, which may mean you probably lost two of the 2GB modules on different banks. Since FB-DIMMs only function in pairs, it's a possibility (two banks of 4GB, totaling 8GB wiped out).

The best way to troubleshoot would be to take all the RAM out and boot with two modules at time, in order to single out any modules that may be bad. If they're all functioning correctly this way, it's probably a bad riser card. Fortunately, these are relatively cheap to replace if that's the case (they're about $70 or so). If it's indeed bad memory, most 3rd-party modules have lifetime warranties anyway.

 

[GoKyu]

I did reseat them when I opened the case the first time (when I kinda dusted out the computer), but if one of the lights was red at the time, I didn't notice.

I'll do the multiple boot scenario in awhile and check to see that the other chips are working.

Oh, here's a shot of the chips that it sees and doesn't see...looks like the card with all 2gb sticks isn't being seen.


Thanks for the help so far!

 

[GoKyu]

Well, I think I got my answer...

I tried putting what seemed to be the "good RAM" (matched pairs that weren't in slot 1 of the bottom riser card) into slots 1 and 2 of both cards.

Now I'm only showing 4 gigs of RAM (2 2's in each), and the bottom riser card still has a red light by slot 1, which means the RAM that was in there probably isn't bad, and the riser card is.

Where can I get a new riser card for an early 2008 Mac Pro? If I could get it from OWC, that would be great...

 

[ashman70]

There are a number of online stores that sell new and used parts for Mac's mac-pro.com is one that comes to mind, although I have never used them. You could also try Ebay but for a memory riser card I would want some guarantee obviously that it works.

 

[Glen Quagmire]

I'd start off by finding out the part number for the riser card - you want to be absolutely sure you're getting the right part. I'd probably opt for a non-Ebay source for that.

It would probably help to find out the model number for the computer as well - it looks like it's MA970LL/A. See: http://www.everymac.com/systems/apple/mac_pro/stats/mac-pro-eight-core-2.8-2008-specs.html.

A random Google search turned up this site, which does appear to sell the riser card for $100:

http://www.welovemacs.com/macproma970lla1.html

 

[CaptainChunk]

Where can I get a new riser card for an early 2008 Mac Pro? If I could get it from OWC, that would be great...

OWC doesn't really sell Apple OEM replacement parts.

This would be the correct replacement. That's from mac-pro.com.

I wouldn't order from welovemacs.com unless you absolutely had to. Their prices are downright obscene compared to everyone else.

 

[GoKyu]

I wanted to give it a few days before replying ...

I rearranged the memory and completely took out the 2 Hynix 1gig memory sticks (Apple-installed), and suddenly the light on the riser went out ... but if I have those sticks in a different configuration, there's also no light, so the RAM seems ok...

So I did a burn in test for 24 hours with the case off, then 24 hours with the case on...and absolutely no trouble at all.

So whatever it was, looks like it's fine now, I'm just down 2 gigs from 14 to 12.

Thanks again for everyone's assistance, and I bookmarked the link for that riser card, on the off chance that it happens again.

 

[ashman70]

Glad to hear it was only two sticks of RAM and everything worked out.

 

[GoKyu]

...or so I thought...

Quick update: Computer worked great for a few weeks, then started the shutdown thing again. For a few weeks, I literally had to put one riser card in the top slot, then when it would shut down (within a day), I would have to put the other card in the opposite slot. They very rarely worked together at the same time.

Created a new account, and suddenly the machine was staying on 2-3 days at a time, so I plugged my mouse into the front USB, and *shutdown*.

So as of today, I brought it into the Apple store, and of course there were no issues. The funny thing was, they tried to "stress" it at the Genius Bar with some script they wrote, and they were literally amazed that only 2 cores went to 100%, and it was still like 99% idle...obviously these guys have never owned a Mac Pro before

So I left it there for them to diagnose, and hopefully it ends up only being some RAM or a riser card or something. They said 3-5 days, but I'm good with a backup Mini I bought a few months ago...

 

[ratfink]

I had the exact same problem with my 2008 mac pro. The system was shutting off under very little load and seemingly for no reason. I thought it was a replacement graphics card I had recently installed and swapped it back to the old one. My problem then went from power offs to just the display turning off.

I swapped back in the newer GPU and then noticed that occasionally after a reboot the system would only be showing half of my available RAM. I vacuumed out the riser cards and removed a large dust bunny and my problems went away. It's now been several weeks since I've had any problems. Since you've already been swapping them in and out I imagine they aren't covered in dust.. but you may want to check for dust in the fans and grills.

 

[nitansing]

Same cpu same problem / What was the solution?

Hi GoKyu,

I'am experieng the same problem right now and just in the middle of an asignment.

What was the problem? And how did you solved it?

Hope to hear from you.

You could reply me on nitan@nitansing.com if you want.

Cheers,

Nitan

 

[WelshDog]

I had the same problem with the same model last year. Apple had it in the repair shop 3 times and could not get it to fail. Ultimately Applecare ran out and I was stuck with a system no one could use. I bought a power supply online and replaced it myself. It's been rock solid ever since.

 

[npaisnel]

I have just had the same problem..random shut downs..some times with re boot,,sometimes not.

Checked system info and yep, one memory slot shown gas empty...sicne they are filled in pairs..obviously wrong.


Will open up and see ..but guess i'll see a red light too.

It is Crucial memory, so they do replace for free

 

[kimsfx]

MacPro 3,1 Unexpected Shutdown

I have an Early MacPro 3,1 Quad-Core Intel Xeon 3.2 GHz machine with 18GB of Ram and running an Apple NVIDIA GeForce 8800 GT that was ordered with the machine.

Only in the last few weeks has my machine started to exhibit the same issues as described here. I know it is not a cooling issue and the power supply is rock solid that I can tell.

From what I read online it could very well be my video card. I have checked and run diags on just about everything I can, but nothing shows up. There is nothing in the console to show a heating issue and my A & B Core amperage run from 18A to 40A on average. Video card draws a constant 1.54 amps and rarely sees anything near 2 amps.

Talk about a strange puzzle with one very very odd occurrence. When a shutdown happens, there are times when I try to restart and it will shut off just a soon as I press the button.

This seems to be a heating issue but I can't find it.

Any thoughts?

Would love a direction to go in. info@adod.com

 

[Macsonic]

I have an Early MacPro 3,1 Quad-Core Intel Xeon 3.2 GHz machine with 18GB of Ram and running an Apple NVIDIA GeForce 8800 GT that was ordered with the machine.

Only in the last few weeks has my machine started to exhibit the same issues as described here. I know it is not a cooling issue and the power supply is rock solid that I can tell.

From what I read online it could very well be my video card. I have checked and run diags on just about everything I can, but nothing shows up. There is nothing in the console to show a heating issue and my A & B Core amperage run from 18A to 40A on average. Video card draws a constant 1.54 amps and rarely sees anything near 2 amps.

Talk about a strange puzzle with one very very odd occurrence. When a shutdown happens, there are times when I try to restart and it will shut off just a soon as I press the button.

This seems to be a heating issue but I can't find it.

Any thoughts?

Would love a direction to go in. info@adod.com

Sorry to hear about your Mac Pro's random shut down problems. It may still be your power supply or maybe your ram though I may be wrong. We had an iMac in the office that shuts down at random and after some check ups, it was traced to a faulty power supply. Power supply was replaced and the iMac was running fine.

 

[kimsfx]

I was hoping not to replace the power supply even though it it could be just about anything at the moment. I can do the job in house, it's just an expensive fix right now.

Have you heard of the video card causing these problems as well?

Thanks
K

 

[treo360]

Somewhat of the same problem for me. Christ it's annoying. Mine wont even sleep. It just shuts down.

Power supply then?

 

[rsps]

Mc Pro Shutting down or not starting issue

The best solution to the problem is not hardware, but it is a software issue.
Found it out after a long and hard process of elimination.
Delete extra junk, get rid of Java, and use Techtool Pro 7.05 to fix your hard drives. It will purr… like a cat.