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jfobart · Oct 15, 2009, 05:06 PM

My MacPro is several years old, 2.5 I believe. It's a 4x2.6GHz. It's been as stable as a rock, totally reliable (I travel around with it a lot and carry it in custom Tenba cases, etc)

Well, sudeenly Ipulled it out of its case the other day and it won't boot. Very strange, so I reseated everything (memory, memory riser cards, hard drives, video card), and still no boot.

What happens is:
1. hit the power button. Button lights up and you hear the machinery start to crank (fans spin up, etc).
2. Instead of hearing the boot tone, within 10 seconds or so all of a sudden the CPU fans run up to 100% and just stay full throttle- just like what happens in a kernel panic.

So I tried one more round of unseating and reseating all the cards and drives, still no boot (it never outputs a video signal even).

I tried pulling all the drives except the boot drive. Problem continues.
I tried booting off of my internal bootable backup disk, the problem continues.

Anybody else have any other ideas before I just have to lug this thing down to the Apple Store nearest to me?

Thanks for the help guys. I've been doing some searching and haven't come up with anything yet... I hope this machine didn't just give up the ghost all of a sudden!

reader50 · Oct 15, 2009, 05:28 PM

Video card or a hardware issue. Does the power light blink? If so, how many blinks to a cycle?

Also, the diagnostic LEDs on the motherboard. Which ones are lit? The CPU LEDs will light up in the event of a failure. To read the other ones, you have to press the diagnostic button beside the LEDs after trying to boot.

seanc · Oct 15, 2009, 06:09 PM

Indeed, I would be thinking that the CPUs need to be reseated next, although, have you tried taking out various pairs of RAM?

I was dealing with a fussy Dell PowerEdge 1900 that had been moved to storage and back again. It was having a number of issues, some which resulted in it not starting up and blaring it's numerous fans at full speed. Fortunately for me, it had a diagnostics screen on the front telling me why it was failing - it was RAM.

jfobart · Oct 16, 2009, 01:14 AM

Hmmmm. Drug the tower back out of the case tonight to keep working on this- and it fired right up. Cruised along just fine.

Hopped on my network via ethernet and started to copy some new work over to the computer. Decided to play a CD... so I hit the cd eject button on the keyboard - and BAM! Screen goes dark, and then the fans slowly start ramping up till their running full tilt.

No blink code on the front, no LEDs. Strange.

I'm on the phone with AppleCare right now setting up an appointment. Ugh, this thing is got some serious issues.

reader50 · Oct 16, 2009, 01:27 AM

Probably a failing power supply based on your description. No LEDs even when you push the LED test button means the motherboard isn't getting the trickle supply from the PS.

AKcrab · Oct 16, 2009, 01:50 AM

I don't know.. The last failure happened with the machine fully booted. Normally when a power supply fails you lose all power.

I'm leaning toward logic board or processors. He needs to get it into a shop.

seanc · Oct 16, 2009, 02:06 PM

Sometimes power supplies will fall over while running if a capacitor is flakey, but i'm not at all expecting that on a 2006 Mac Pro.

Doc HM · Oct 16, 2009, 06:00 PM

I'd also be leaning away from power supply. The fans ramping up would indicate a good power supply. Ramping fans normally indicates either cpu or logic board.

jfobart · Oct 17, 2009, 03:29 AM

Well I got it dropped off at an authorized service center here in Atlanta today (Onyx Consulting). We'll see what they say next week when they call with the diagnosis.

Thanks for all the ideas guys, I'll let you know what I found out next week when I hear from the shop.

Snow-i · Oct 20, 2009, 01:32 AM

I have a pc with similiar problems...I suspect the aging video card in it.

Power on, fans full blast, and no video output. I'm hoping its not the proc or motherboard...those are the newest...I also just put 4 gigs of crucial ram into it about a month before it decided to play tricks with me. When i get some cash and a day off i'll tear it apart. Let me know what they find, it might help me find a place to look :-)

In other news, my 4 macs are humming along nicely :-)

seanc · Oct 20, 2009, 02:11 PM

Get a speaker for the internal motherboard connector, then you'll know what it's doing if it beeps.

I guess you should open a thread in the Lounge for that.

jfobart · Oct 23, 2009, 01:45 AM

Heard back from the shop yesterday - they said bad logic board. Uh oh....

The shop called today (24 hours later) and said, nope, not the logic board, bad power supply. Ordered the parts, should be in for install tomorrow.... so we'll see how that goes.

jfobart · Oct 23, 2009, 10:11 PM

Heard back this afternoon, and it turns out it was the power supply. He didn't say exactly what was wrong with it (if he knew), but it's been replaced and apparently the machine is fixed and ready for pickup. So AppleCare saves the day and gets it taken care of it looks like.

Yeah for AppleCare!