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Mac Pro 5,1 died twice. Need help

axPoindexter

axPoindexter

macrumors newbie
Original poster
May 31, 2009
15
1
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Specs: 2010 Mac Pro 3.46GHz, 24GB RAM, GTX680, Sonnet Pro PCIE with 2TB RAID 0 SSD, and RAID 10 6TB on 5,1

3 weeks ago I left the computer running overnight as I usually do and came back to it completely bricked. No lights, no nuthin! So, I went through the manual's steps and went through the steps to the point where I bought a new (used) PSU. PSU arrived, put it all back together and the machine fired-up like normal. The first few nights I shut the machine down. And then went back to my normal procedure of letting it stay on overnight. Next morning it was bricked again.

What could be causing this?

As far as power from the wall goes: it has a clean shot straight to the breakers on a 20 AMP fuse with roughly a 30 foot run. This machine lived on this run for a good 6 months. Off the outlet is a Cyberpower 1350 UPS that only has a single surge off of it for the sole purpose of having the Mac be the trigger to turn the peripherals on/off. And that setup has been with this mac for a good year and a half.

Thanks in advance for any help.
 
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Someone correct me if I am wrong, but I think if you are going to use a UPS with a Mac Pro it needs to be pure sine wave.
 
What pointed u in the direction of a faulty psu. Was there trickle power coming through when u pressed the MB button above the front fan? If u did, did u see the yellow led light up?
Next, did u remove all components i.e. All connected peripherals like PCi cards etc and leave just the OS drive and RAM in and then test?
 
Reset PRAM/SMC.

Got any USB or other external storage devices? Try unplugging those overnight. USB hubs as well. I've seen lousy USB devices lock up a machine before.

Make sure all fans are spinning while the machine is on, including the GTX 680's fan.

Blast the dust out of everything, especially the CPU cooler and the GPU's shroud assembly.

Read up on broken Mac Pro northbridge retainers. This may be your culprit.

Check SMART data on your disk drives.

Try removing 1 RAM stick at a time.

Man Pro's will run fine on the worst of UPS's square wave power, even non-stepped with 100% distortion. Not a good idea, but it'll run. If you unplug the UPS from the wall and the Mac keeps going, then that's not your problem.
 
Completely bricked no matter where I plug it in. No lights, no nothing. This is what happened on the previous PSU too. So, I can only imagine another component has gone funky.

Last time I reset everything and even pulled most hardware apart (RAM was the first thing) except for MB/CPU items. I even replaced the PRAM battery. I still have not checked currents on rails yet. Spending $180 on a new PSU was simple enough and figured if that didn't work it was something "deeper."

I'm going to start researching broken Northbridge retainers now....
 
axPoindexter said:
Completely bricked no matter where I plug it in. No lights, no nothing. This is what happened on the previous PSU too. So, I can only imagine another component has gone funky.

Last time I reset everything and even pulled most hardware apart (RAM was the first thing) except for MB/CPU items. I even replaced the PRAM battery. I still have not checked currents on rails yet. Spending $180 on a new PSU was simple enough and figured if that didn't work it was something "deeper."

I'm going to start researching broken Northbridge retainers now....
Click to expand...

Don't trust external peripherals either. They have DMA access. That's all that's needed to hard lock a machine.

It could be a drive acting badly as well. Not likely, but possible.
 
axPoindexter said:
Spending $180 on a new PSU was simple enough and figured if that didn't work it was something "deeper."

I'm going to start researching broken Northbridge retainers now....
Click to expand...

So is the new PSU also showing no signs of life? Check with a voltmeter to see if any sign of power is coming through. Sounds to me like something gone awry on the backboard.
If u have a friend with a similar mac try putting your system tray into his and if all goes well u know it's your backboard. Simplest form of negating a system tray issue that I know of
 
With all components plugged in I got the red confirmation light when plugging the cord into the Mac. Hitting the power button gives a noise like the PSU is trying to start, but nothing happens.

I've tried powering up without any PCI cards connected and have tried it with each RAM stick on their own. Same thing every time. I have not pulled the CPU cooler to check connections there yet.

Fortunately I've learned how to get by on just my laptop, but this is going to get old when it comes time to do some editing.
 
It's down to CPU, northbridge heatsink issue, CPU tray, or motherboard.

CPU, could be improperly seated or too much/not enough tension on heatsink screws.

Northbridge, if you see one or two of the clips are popped off, the chip may be cooked.

Beyond that, time to look for a mobo or CPU tray. Single-CPU trays can only work properly with single-CPU motherboards due to fan control firmware. Same goes for dual. There may be a workaround, but I don't know of one.

May be better served looking for a 5,1 with a beat up case for cheap and swap tray and mobo. May be a time to consider swapping to a dual-socket system in the process if the price is right and your uses would benefit from more cores/RAM.
 
Maybe it's a sign......a sign for 6,1.

EDIT: all kidding aside....still can't it to work?
 
When I get back in town I will try to reseat the CPU with some new thermal paste. Will also check other connections at that time.

If it doesn't work after that I'll have some nice upgrades for sale and a new MBP for me.
 
Welp. I'm officially calling it dead. After reseating the CPU, replacing the PSU, and checking and rechecking just about every connection I'm full out of ideas. It is probably something on the board, but I'm done putting money into this brick.

Too bad because I really really really loved the performance on this machine and am sooooo not thrilled by any of the current Macs. My plan is to see how long I can run on my O.G. 2012 Retina.
 
Had a similar experience with a 4,1 Machine that was flashed to 5,1. Machine shut off randomly while I was using it. After much investigation and diagnosing I determined it had to be the PSU as nothing would light up or stir when the power button was pressed, even with just about everything disconnected.

After looking at the absurd on-line prices for PSUs for this machine and not knowing whether it was ONLY the PSU and not a combination of other things, I didn't feel like going down that rabbit hole and cut my losses. It was pretty tough sending that machine off to the recycler since I had it for almost 6 years and upgraded the dual CPUs twice, ram, SSD, and graphics cards along the way.

It's certainly possible you got a dud PSU as a replacement, but I'm in agreement that it was probably the best decision to cut bait there.
 
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