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Help, Mac Pro 4.1 8 core black screen boot loop.

C

caronte23

macrumors newbie
Original poster
May 6, 2011
26
0
Hi everyone, I mentioned what happened in the delidding thread, but I'd like to make a new one, hopefully somebody can help.
Here's what happened:
My Mac Pro was running firmware 5.1, Sierra and all stock hardware (2x2.26 CPUs, 6GB 1066RAM etc)
I delidded 2 x5680s and put them in, slightly ruined the side of the pcb on one of them, I put the ruined one in slot B.
Everything powered up and both Cpus were recognised, but 2 mem sticks on the cpu B side were not recognised.
I shut down and tried a PRAM reset and that's when the loop began. It restarts once (2 Chimes) and then shuts off, If I try another PRAM reset it restarts twice and then shuts off. (3 Chimes)
This is with both the new CPUs and the stock ones.
At the moment I've put everything back to stock, but no success..
If I put the 2 x5680s in the usual 2 slots of ram on cpu B leds light up... So I suspect the dameged one creates this issue.
Now during all of this I noticed I was missing a Plastic rivet holding the northbridge heatsink, followed some user's advice to temporairily fix it with some zip ties, now the heatsink is safely secured but the problem persists...
Please someone help me troubleshoot this, is drving me insane!
 
Test you Mac Pro with another tray, preferably a single CPU. You have to much things gone wrong already.

Begin where you have a reliable staring point, then go on troubleshooting.
 
tsialex said:
Test you Mac Pro with another tray, preferably a single CPU. You have to much things gone wrong already.

Begin where you have a reliable staring point, then go on troubleshooting.
Click to expand...
I wish I had the means to do that :/
 
caronte23 said:
I wish I had the means to do that :/
Click to expand...

Unfortunately you will have to find another tray, you have CPU and northbridge problems to diagnose and these are very tricky to solve with 2009 dual CPU trays.

Take a step back, get your Mac Pro fully working with a cheap single tray, I bought one recently for less than $60, then you start to diagnose the problematic dual CPU tray.
 
tsialex said:
Unfortunately you will have to find another tray, you have CPU and northbridge problems to diagnose and these are very tricky to solve with 2009 dual CPU trays.

Take a step back, get your Mac Pro fully working with a cheap single tray, I bought one recently for less than $60, then you start to diagnose the problematic dual CPU tray.
Click to expand...
I don't know, even if I put in a single tray and then it worked I'd be back at step 1 again :/
Today I'll try to replace the zip ties for the northbridge with screws, who knows..
Also I have a question, I did the firmware update a while back and I can't remember for sure whether I turned crsutil back on, although I'm fairly confident I did. Could that cause such a problem after a PRAM reset?
Also, doesn't the fact I get the Chime sound mean at least something's good? Like cpus are recognised etc?
 
caronte23 said:
I don't know, even if I put in a single tray and then it worked I'd be back at step 1 again :/
Click to expand...
You will have a working Mac Pro for cheap, no? A dual CPU tray for a 2009 is at least $400.

With a single one you can test a Xeon before doing the de-lid process, to be sure that you got a working one.
[doublepost=1551447403][/doublepost]
caronte23 said:
Also I have a question, I did the firmware update a while back and I can't remember for sure whether I turned crsutil back on, although I'm fairly confident I did. Could that cause such a problem after a PRAM reset?
Click to expand...
No.

BTW, Mac Pro 4,1 don't have PRAM, just NVRAM.

When you clear a Mac Pro 4,1/5,1 NVRAM, SIP goes back to enabled.

Also, doesn't the fact I get the Chime sound mean at least something's good? Like cpus are recognised etc?
Click to expand...

Something is working during the post process. Try to get it working with the original processors, simplify your troubleshooting.
 
tsialex said:
Something is working during the post process. Try to get it working with the original processors, simplify your troubleshooting.
Click to expand...

I have put the original CPUs back in, that's were I'm at atm, the good thing is that the RAM leds are all turned off where as with the 2 x5680s 2 slots are not recognised on slot B
 
caronte23 said:
I have put the original CPUs back in, that's were I'm at atm, the good thing is that the RAM leds are all turned off where as with the 2 x5680s 2 slots are not recognised on slot B
Click to expand...
When testing one CPU with a dual CPU tray, you have to use slot-A only. Start with just one of the original Xeons into CPU-A, after you get it going install the second one.
 
tsialex said:
When testing one CPU with a dual CPU tray, you have to use slot-A only. Start with just one of the original Xeons into CPU-A, after you get it going install the second one.
Click to expand...
I'm gonna try, but I have little faith because I already tried with 1 x5680 only in slot A and no CPU or ram in slot B, I got the exact same reboot problem but with fans at full speed, although when I did that test I hadn't fixed the northbridge back..
 
caronte23 said:
I'm gonna try, but I have little faith because I already tried with 1 x5680 only in slot A and no CPU or ram in slot B, I got the exact same reboot problem but with fans at full speed, although when I did that test I hadn't fixed the northbridge back..
Click to expand...
Fans will always go to full RPM when you don't have a CPU into socket-B, it's a fail-safe protection.
 
tsialex said:
Fans will always go to full RPM when you don't have a CPU into slot-B, it's a fail-safe protection.
Click to expand...
Yes, I figured, but just to be clear I should test with no cpu and no heatsink in slot B correct?
 
tsialex said:
No CPU, heatsink or RAM into socket-B.
Click to expand...
Nope, nothing, I went and fixed the northbridge cooler with screws and springs, tried with only cpu A and ram on A, nothing, same exact issue. I boot it, it chimes, then it reboots I get a second chime ancd the fans start going and then shuts down after maybe 10-15 secs.
If I do a NVRAM reset it chimes once then reboots chimes again, fans start going, reboots again with a chime and then shuts down :(
 
Still nothing, the only piece of info I got that hopefully could suggest some solutions is that there's an led that blinks once when I press the power button and then again when it shuts down, not when it restarts, and it's labeled D51510.
Doing some research I found a thread where somebody said they had that led lighting up and it was the northbridge heatsink rivets. But it didn't say for him whether it blinked or stayed on.. also I'm pretty confident I've fixed the northbridge heatsink at this point.
The LED is located on the right between the ram slots and heatsink A
 
caronte23 said:
Still nothing, the only piece of info I got that hopefully could suggest some solutions is that there's an led that blinks once when I press the power button and then again when it shuts down, not when it restarts, and it's labeled D51510.
Doing some research I found a thread where somebody said they had that led lighting up and it was the northbridge heatsink rivets. But it didn't say for him whether it blinked or stayed on.. also I'm pretty confident I've fixed the northbridge heatsink at this point.
The LED is located on the right between the ram slots and heatsink A
Click to expand...
Powers on momentarily when you press power on.

So, you tested everything, the only thing that you can do now is try to find a cheap tray.
 
Macschrauber said:
Inspect the cpu sockets with a microscope or a decent camera, even for dust pieces.
Click to expand...
Thanks I'll look into that, although I've checked with my naked eye I couldn't see anything..
At this point I'm a bit out of options, if there's anybody in the UK that can look into it I'd be more than happy to ship it over..

Is it possible that the BIOS got corrupted? If so where is it located, on the tray board or the main one?
 
Last edited:
caronte23 said:
Is it possible that the BIOS got corrupted? If so where is it located, on the tray board or the main one?
Click to expand...

Macs don't have BIOS, the BootROM is located on SPI flash on the backplane, it's U8700 component near the PCIe AUX A and B.

CPU trays don't have any firmware besides the one into the SMC micro controller, but this one you can't read and it's pre-programmed from factory, so forget about that.
 
tsialex said:
Macs don't have BIOS, the BootROM is located on SPI flash on the backplane, it's U8700 component near the PCIe AUX A and B.

CPU trays don't have any firmware besides the one into the SMC micro controller, but this one you can't read and it's pre-programmed from factory, so forget about that.
Click to expand...
Ok thanks, so is it possible the the BootROM got corrupted on the backplane? Because if that was the case then even a new tray wouldn-t help...
 
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