2008 Mac Pro Won't Boot/Reboots On Startup

[The Buggman]

I'm "running" a 2008 Mac Pro (3,1) that's refusing to boot any OS or from any HDD. If I attempt to boot into a Mac OS/Recovery, it begins the start-up process (as indicated by the loading bar under Apple logo) and continues to slowly trudge along up to nearly halfway before it reboots. Sometimes it includes the obvious error screen stating 'Your computer restarted due to an error.' If I attempt to boot into Safe Mode, it freezes on the bootup screen just after removing the load bar. If I try to boot into Windows, it freezes on a black screen.

I've tried removing components one by one, including: Keyboard & Mouse, Various HDDs (I have two HDDs from which I may boot + other storage), RAM (Pulling them, reordering them, etc.), Capture Card (BlackMagic Intensity Pro), and I'm working on getting access to a replacement GPU to test.

I've also tried resetting NVRAM and SMC. There have been no changes. I'm at the end of my rope. Please, someone tell me it isn't what I think it is. I've been on the fence about upgrading my GPU for years due to cost. I don't want to have to buy a new motherboard as well.

Please, someone save me with a cheap fix!

 

[h9826790]

Possible GPU. If it's half failed, the computer may still able to show you the Apple logo, however, it may stuck when loading the driver, which will stuck at the loading bar / black screen on Windows.

Of course, it could be something else, GPU is just my rough guess.

 

[OS6-OSX]

Please, someone tell me it isn't what I think it is.

Don't know what you think it is but if it includes the letters PSU, here is a route to take:
1. Take it out and give it a good shot of air.
2. Blow the rest of the MP out while it's open (including ram slots)
3. http://www.macpartsonline.com/661-4...-mac-pro-2-8-3-0-3-2ghz-early-2008-a1186.html
4. http://www.dvwarehouse.com/661-4677...ac-Pro-Early-2008-614-0409---NEW-p-35735.html
5. https://www.ifixit.com/Guide/Mac+Pro+First+Generation+Power+Supply+Unit+Replacement/32222

 

[filmak]

what GPU do you have?
Is it a 8800?

 

[The Buggman]

Sorry for the wait...

View attachment 571408
Don't know what you think it is but if it includes the letters PSU, here is a route to take:

That's definitely worth trying. I'll give it a sh--... a try.

what GPU do you have?
Is it a 8800?

Yes, it is an 8800.

Possible GPU. If it's half failed, the computer may still able to show you the Apple logo, however, it may stuck when loading the driver, which will stuck at the loading bar / black screen on Windows.

Of course, it could be something else, GPU is just my rough guess.

I finally managed to get ahold of a GPU to try. Unfortunately, it's a PC GPU, so it, by itself, didn't work. But, after trying it, I went back to my own GPU (the 8800) and the computer fully booted! The PC GPU was also an NVidia card which makes me think maybe it is some sort of driver issue that was partially resolved by the attempt?

The problem of the computer randomly rebooting still persists. Upon one boot attempt, my desktop came across as a garbled mess which further pushes the idea of it being a graphics issue. That said, it has been a long time (read: never) since I've aired out the PSU, so I'll likely be doing that regardless. Also, is there some problem with the 8800s that I should know about?

 

[MacVidCards]

Bake it.

Sounds like standard 8800GT death.

Set up screen sharing and boot without card, you'll know

 

[The Buggman]

Bake it.

Sounds like standard 8800GT death.

Set up screen sharing and boot without card, you'll know

Oh, it's you! I'm not around these forums often, but I was just reading about you and your attempts to get the GTX 9xx series up and fully functioning on Macs. I think the posts were from last year. Has this happened yet? It looks I'm in the market for a new card now and I've had my eye on the 970...

Edit: I just saw in your store that not only do you carry them, but you offer a flashing service for them as well. They're a bit too expensive for me at the moment, but should purchase one in the future, is there anything I might need to be prepared for beforehand? Should I expect any round-about issues when it comes to system updates with one of these flashed cards installed?

 

[MacVidCards]

I rec'd 970/980 with the 3 display ports. Gives more and better options in the future.

I am serious about 8800 and baking.

When we sold them, they would die quite often. I kept a tub labeled "bakers" and when it got more then 10@ 8800s in it, I would fire up the oven. Had a 50% resurrection rate. The cards that showed things on screen then got corrupted were far more likely to come back form the dead then the cards that stayed black at boot.

Many threads on this, I do recall that I used foil balls to keep cards off the baking sheet. I seem to recall 375-420 F for 9 minutes was the magic combo. If caps start popping or components start raining down from backside, you went too long. Check past threads, several people I told to do this had success, even if just to keep machine running while new card found.

 

[The Buggman]

I am serious about 8800 and baking.

What is the exact reaction which causes baking them to work? One of the forum posts mention the 8800s have weak soldering joints. Is the baking meant to address that issue directly? If so, I know a guy who, supposedly, may actually know how to fix that with his soldering tool. Is baking still better?

 

[MacVidCards]

The solder that breaks is on a BGA. (Ball Grid Array) so one of several hundreds of tiny little balls. Lead was bad for humans but better for soldier then the things it got replaced with. I have a 60" Plasma that has been brought to it's knees by same lack of lead. The replacement metals are more brittle, and over time they crack due to thermal stress. As you pointed out, once the card is completely non-functional, there is nothing to lose by baking,

Must remove fan, with 8800 it is absolutely crucial that board never gets flexed or bent. If you lay it face down to take screws out, very important to have the bracket hang over the edge of a table, just that tiny 1/16 " will cause card to flex and break more joints.

 

[filmak]

Nice and detailed reply from MVC.

Imho baking is a way to fix the card temporarily, anyway usually, sooner or later, you will need to bake it again and again until its final death.
I had the same card in a MP 3,1 2008...
I think it's better for you to start looking for a replacement GPU.

 

[The Buggman]

Update! So I've gone through the baking procedure and, at the very least, I didn't outright murder the card. It took a while for the thermal pads and compound to arrive, so this is me having just put everything back together and booting up for the first time. I think I'm going to let the paste settle more before I test anything that might beat on the GPU. Also, the thermal pads I received were the wrong ones, so I ended up continuing with the original pads for now.

Thanks, MVC, for all the amazing help. Thank you everyone who replied to offer their support.

I guess now I just try to hold out for that 970...