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Mac Pro Will not boot! Not a PSU issue...

H

highdefw

macrumors 6502
Original poster
Apr 19, 2009
259
0
Hey guys, I really need some help with my Mac Pro, and not sure where else to go from here...

It started when I plugged in a 7port usb hub into the front usb port on the MP. When I plugged the AC adapter in the wall outlet for the hub, the computer went straight off.

Since then nothing will power on. The most I was able to get was the 5V STBY LED to light up when I hit the DIAG button. I have taken it to apple, but because I built the machine from sourced apple parts, the system as a whole is not recognized by Apple's database. This meant that the Apple genius could not perform a full diagnosis. He was able to determine that the PSU was definitely dead, and my backboard should be alright because the DIAG LED was still lighting up.

Well since then, I have replaced the PSU, and the front board usb panel. Unfortunately there's still no booting. Not sure what to do now. I tried removing all the hardware to the bare limit as stated by apple's service manual, but I got no where.

Now I'm leaning towards the backboard being the issue, even though the DIAG LED lights up. Originally I tried jumping the computer using a paperclip on the PWR Pads on the backboard, but nothing happened.

Any ideas on what I can do next? Not sure what else I can do...

P.S. Any chance it could be the physical power button that connects to the front board? Maybe I wasn't jumping it right, and the button was just unresponsive since the shock...

Thanks,
highdefw

Thanks for your help!

-Naren
 
highdefw said:
Hey guys, I really need some help with my Mac Pro, and not sure where else to go from here...

It started when I plugged in a 7port usb hub into the front usb port on the MP. When I plugged the AC adapter in the wall outlet for the hub, the computer went straight off.

Since then nothing will power on. The most I was able to get was the 5V STBY LED to light up when I hit the DIAG button. I have taken it to apple, but because I built the machine from sourced apple parts, the system as a whole is not recognized by Apple's database. This meant that the Apple genius could not perform a full diagnosis. He was able to determine that the PSU was definitely dead, and my backboard should be alright because the DIAG LED was still lighting up.

Well since then, I have replaced the PSU, and the front board usb panel. Unfortunately there's still no booting. Not sure what to do now. I tried removing all the hardware to the bare limit as stated by apple's service manual, but I got no where.

Now I'm leaning towards the backboard being the issue, even though the DIAG LED lights up. Originally I tried jumping the computer using a paperclip on the PWR Pads on the backboard, but nothing happened.

Any ideas on what I can do next? Not sure what else I can do...

P.S. Any chance it could be the physical power button that connects to the front board? Maybe I wasn't jumping it right, and the button was just unresponsive since the shock...
Click to expand...
Ouch.

Sounds like the USB hub's PSU blew the MP's PSU. And the MP PSU failure then damaged some of the internals in the MP (cascade failure; seen this sort of thing before). If you're lucky, it's the Power Switch board. Or the logic board if you're not (around $800 last I saw for new), and it can actually be worse (even took out the CPU's and/or other parts of the system, such as HDD's, ... :eek:). :(

Failed PSU's can turn out to be nasty (voltage reg/s fry and AC voltage reaches other parts of the system = toasted gear).
 
highdefw said:
I replaced the battery and tried that method already, but not resetting the SMC controller. There are no buttons on the backboard besides the RTC and DIAG button. The rest are all pads. I'll try jumping them with a paperclip, but is there anything else specific I should do?
Click to expand...

So you did NOT reset the SMC via the button, but what about other methods?
What model board did you procure? What do you mean by "pads"? Did you press the button shown in the second link? I think you said you did not have said button?
 
derbothaus said:
So you did NOT reset the SMC via the button, but what about other methods?
What model board did you procure? What do you mean by "pads"? Did you press the button shown in the second link? I think you said you did not have said button?
Click to expand...

This is what I mean... pads

I believe I have to connect all four pads at the same time? This board is not in any of the service manuals I have... it's slightly newer.

Right now I think my issue is because of the whole power incident, the board needs to be reset for a cold start. All I replaced so far was the PSU and the front power board. According to the Apple genius and what I've researched, my backboard and everything else should be ok.
 
Last edited:
Alright well I tried resetting the SMC and still no boot. Looks like the backboard needs to be replaced. Gonna try to test the lower tray before buying anything else. No point spending $300 if the $2000 tray is fried...

Wish me luck...
 
highdefw said:
Alright well I tried resetting the SMC and still no boot. Looks like the backboard needs to be replaced. Gonna try to test the lower tray before buying anything else. No point spending $300 if the $2000 tray is fried...

Wish me luck...
Click to expand...
It may be the daughterboard, or even both. :eek: :(

BTW, a daughterboard (tray) was ~$300USD last I saw (bare, no CPU's or memory).
 
Good luck. An unfortunate situation to spend or not. How much are you into this thing already? At some point you have to stop the bleeding if you can't pinpoint the exact part. It'll end up being the Ford Taurus of Mac's.
 
The Apple Service manual leaves out one critical piece of hardware for when the machine won't turn on: The memory riser cards. If your machine is one of the ones with separate memory riser cards, pull both of them out and try again.

I've seen surges go through a power supply and logic board just to fry a video card on an iMac, and I've seen a lot of RAM fried due to surges. Sure, it's easy to be suspicious of what's near the source of the surge, but that doesn't have to be the weakest link.
 
derbothaus said:
Good luck. An unfortunate situation to spend or not. How much are you into this thing already? At some point you have to stop the bleeding if you can't pinpoint the exact part. It'll end up being the Ford Taurus of Mac's.
Click to expand...

So far about $200. Regardless I need a workstation. So looks like Im replacing the backboard. If it's the daughterboard, then I will repurchase, but install only one hex cpu for now.

Detrius said:
The Apple Service manual leaves out one critical piece of hardware for when the machine won't turn on: The memory riser cards. If your machine is one of the ones with separate memory riser cards, pull both of them out and try again.

I've seen surges go through a power supply and logic board just to fry a video card on an iMac, and I've seen a lot of RAM fried due to surges. Sure, it's easy to be suspicious of what's near the source of the surge, but that doesn't have to be the weakest link.
Click to expand...

The 2009 MP doesn't have memory risers. All RAM is on the daughterboard which is shared with the processors.
 
Great news everyone, Mac Pro is back running again. In the end, the PSU, front panel usb board, AND the backboard panel needed replacing. The gpus, hdds, and processor tray were untouched.

Thanks for the help!
 
highdefw said:
Great news everyone, Mac Pro is back running again. In the end, the PSU, front panel usb board, AND the backboard panel needed replacing. The gpus, hdds, and processor tray were untouched.

Thanks for the help!
Click to expand...

What was the cause for sure you know? Kind of concerning if it was just a USB hub that caused all this, or maybe there were other factors and it was all just a messed up coincidence?
 
Tucom said:
What was the cause for sure you know? Kind of concerning if it was just a USB hub that caused all this, or maybe there were other factors and it was all just a messed up coincidence?
Click to expand...

It was the usb hub, but more specifically, the AC adapter the hub was connected to. It definitely affected the Pro because it did the same thing to my rather new 24 led cinema display. The second that AC adapter plugged in, the display and monitor went off.

Display works now, but every time I plug the main usb cable into a Mac or any kind, I get a over-surge error, and the usb ports power off (along with the iSight camera...). At least the physical display works.

-highdefw
 
highdefw said:
It was the usb hub, but more specifically, the AC adapter the hub was connected to. It definitely affected the Pro because it did the same thing to my rather new 24 led cinema display. The second that AC adapter plugged in, the display and monitor went off.

Display works now, but every time I plug the main usb cable into a Mac or any kind, I get a over-surge error, and the usb ports power off (along with the iSight camera...). At least the physical display works.

-highdefw
Click to expand...

I think that's just bizarre, but I guess not too farfetched, still, all those problems due to a USB hub? Is this due to a poor surge-protection setup on the Mac Pro I wonder or would it happen with any PC (OS X or Windows setup), and it's just that ofcourse it's a well built machine, but ofcourse that could happen for any number of reasons (again, not to say the Mac Pro isn't built or designed badly in this area), but just kinda odd it's from a USB device that can cause all this :confused:

Then again when any sort of electronic device is used improperly (in this case a low quality PSU for the USB hub or faulty or something) then anything can happen (become immortal etc.), but you'd think that these hubs would be recalled or something? Or are Mac Pro USB ports just fickle?
 
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_2 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8H7 Safari/6533.18.5)

Here's the eBay item number: Item #: 130500609168

Didn't but it from these guys directly, but it's the exact same hub. It's sold EVRYWHERE!! amazon, eBay, etc... Very generic. I used it for a good few months before it gave.

And yes I use a very good surge protector, for the last year or so. Everything was normal until
I needed to use the hub again after a couple months.
 
Tucom said:
I think that's just bizarre, but I guess not too farfetched...
Click to expand...
I suspect the failure bypassed the safety circuits (Over Voltage and Over Current) in the MP's PSU and surge suppressor it's plugged into by routing (presume AC) over the USB cable that connected the hub to the MP.
 
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