MP 1,1-5,1 Mac Pro, 5,1 booting up issue, crash or reboots then black screen

[cakey]

NMI (Non-Maskable Interrupts) crashes are usually northbridge related, even more so when the kext crashing is com.apple.driver.AppleIntelCPUPowerManagement. Inspect the CPU tray northbridge heatsink push-pins.

If the northbridge overheated because a broken push-pin and cooked itself, you will need a replacement CPU tray. There is no economical way to repair the CPU tray when the northbridge is damaged.

You could also have BootROM problems because of the crashes being saved inside the NVRAM for months, first PanicLog is from Sun Apr 16, but first inspect the push-pins.

Wouldn't the temperature readings I attached in the original post show if there was a NB heatsink issue?

I took the two processor heatsinks off and had a look at the NB heatsink push-pins. They look OK.
I have attached some photos.
Thanks.

 

[tsialex]

Wouldn't the temperature readings I attached in the original post show if there was a NB heatsink issue?

Temperature is not a dead giveaway unless the delta is extreme - you have to know how much time the Mac Pro is on, if it's in load, ambient temperature and etc.

I took the two processor heatsinks off and had a look at the NB heatsink push-pins. They look OK.

This is definitively not ok, the arrow point is already too open and will break soon, but it's not the main problem.

I have attached some photos.
Thanks.

This CPU tray is too dirty, the oily residue from the thermal pads + accumulated dust becomes conductive overtime and you start to have crashes. Clean all the mess with isopropanol, re-assemble and test again.

Do you have access to another working CPU tray to check if the problem is only the CPU tray and the rest of the Mac Pro is healthy?

 

[cakey]

Temperature is not a dead giveaway unless the delta is extreme - you have to know how much time the Mac Pro is on, if it's in load, ambient temperature and etc.



This is definitively not ok, the arrow point is already too open and will break soon, but it's not the main problem.



This CPU tray is too dirty, the oily residue from the thermal pads + accumulated dust becomes conductive overtime and you start to have crashes. Clean all the mess with isopropanol, re-assemble and test again.

Do you have access to another working CPU tray to check if the problem is only the CPU tray and the rest of the Mac Pro is healthy?

I don't have another CPU tray.
I will clean the board.
I may as well replace the pins for the NB heat sink too. I bought some a few weeks ago just in case.
Thanks.

 

[cakey]

Temperature is not a dead giveaway unless the delta is extreme - you have to know how much time the Mac Pro is on, if it's in load, ambient temperature and etc.



This is definitively not ok, the arrow point is already too open and will break soon, but it's not the main problem.



This CPU tray is too dirty, the oily residue from the thermal pads + accumulated dust becomes conductive overtime and you start to have crashes. Clean all the mess with isopropanol, re-assemble and test again.

Do you have access to another working CPU tray to check if the problem is only the CPU tray and the rest of the Mac Pro is healthy?

Hi,
While cleaning the CPU tray, the cable that attaches to the NB heatsink disconnected.
It looks like it was glued. And I don't know what the grey stuff is on the end.
Can this be reattached?

Thanks

 

[tsialex]

Can this be reattached?

This is the temperature sensor, you will remove the old thermal glue/epoxy the best you can and then re-apply it.

If you can't find thermal glue/epoxy easily, you can improvise it with 2/3 slow cure/24h bi-component epoxy and 1/3 white silicon thermal paste. Do not use fast cure epoxy, it will break easily when mixed with thermal paste. You will need at least a day to re-install it, but works fine and I've used this formula a lot over the years.

 

[cakey]

This is the temperature sensor, you will remove the old thermal glue/epoxy the best you can and then re-apply it.

If you can't find thermal glue/epoxy easily, you can improvise it with 2/3 slow cure/24h bi-component epoxy and 1/3 white silicon thermal paste. Do not use fast cure epoxy, it will break easily when mixed with thermal paste. You will need at least a day to re-install it, but works fine and I've used this formula a lot over the years.

Great.

I am wondering if that cable was a little loose, it may have been giving a false readout showing the NB HS as lower than it actually was?

I found this. Would it work?

TBS20S - Adhesive, Thermal Bonding System, Epoxy - 2 Part, Syringe, Blue, Cream, 20 ml

TBS20S is a thermal bonding system. It is a two part epoxy bonding system which utilises metal oxides to provide excellent thermal conductivity whilst being electrically insulating. It is especially useful in the manufacture of heatsink assemblies where ‘piggy back’ arrangements are applied and...

uk.farnell.com

Product Overview​

TBS20S​

Adhesive, Thermal Bonding System, Epoxy - 2 Part, Syringe, Blue, Cream, 20 ml
​

Thermal Bonding Compound is a two part epoxy bonding system which utilises metal oxides to provide excellent thermal conductivity whilst being electrically insulating. It is especially useful in the manufacture of heatsink assemblies where 'piggy back' arrangements are applied and where the manufacture design of heat sinks does not allow for welding or brazing techniques to be employed due to complexity or geometry of the fins. TBS is also ideal for use as a bonding medium in surface mounting assemblies. Key Properties: Two part epoxy bonding system Very high bond strength High thermal conductivity: 1.10 W/m.K Eliminates need for mechanical fixing by providing a permanent bond Wide operating temperature range: -40°C to +120°C Includes glass beads for a set thickness to be applied

• Excellent tensile strength.
• Very good thermal conductivity
• Excellent electrical insulation characteristics
• Part A colour: Blue
• Part B colour: Cream
• Package: 20 ml twin syringe system

Thanks

 

[tsialex]

Great.

I am wondering if that cable was a little loose, it may have been giving a false readout showing the NB HS as lower than it actually was?

Very possible.

I found this. Would it work?

TBS20S - Adhesive, Thermal Bonding System, Epoxy - 2 Part, Syringe, Blue, Cream, 20 ml

TBS20S is a thermal bonding system. It is a two part epoxy bonding system which utilises metal oxides to provide excellent thermal conductivity whilst being electrically insulating. It is especially useful in the manufacture of heatsink assemblies where ‘piggy back’ arrangements are applied and...

uk.farnell.com

Thanks

It's not the same type used by Apple, but should work. Any thermal glue with good conductivity will work, some will take more time to transfer the heat to the sensor, but in the end you just need a reliable reading.

Try to remove all the old thermal glue before applying the new one, also clean the heatsink pocket for the sensor.

 

[cakey]

Very possible.



It's not the same type used by Apple, but should work. Any thermal glue with good conductivity will work, some will take more time to transfer the heat to the sensor, but in the end you just need a reliable reading.

Try to remove all the old thermal glue before applying the new one, also clean the heatsink pocket for the sensor.

The grey stuff on the sensor, is that the thermal glue too? It looks like something else compared to the orange coloured stuff left on the cable.

 

[tsialex]

Grey is old thermal epoxy glue. The temperature sensor is a black plastic TO-92.

TO-92 - Wikipedia

en.wikipedia.org

 

[cakey]

I glued the sensor to the NB HS.
One question. The CPU heatsinks have this pink strip as shown in the photo. On touch, it feels a little tacky, like there was something on it.
Do I need to put anything on it, or just clean it?
Thanks.

 

[tsialex]

If the thermal pads are degraded, you need to replace it. There is a thread about the thermal pads.

I'd clean the current one first, reassembly everything and test the CPU tray to be sure that it is working correctly.

 

[cakey]

If the thermal pads are degraded, you need to replace it. There is a thread about the thermal pads.

I'd clean the current one first, reassembly everything and test the CPU tray to be sure that it is working correctly.

I re-assembled everything.
It booted normally, and I had it on for a couple of hours last night. The NB diode temperature peak was 77c peak and NB HS peak was 65c.
This morning, I turned it on for 20 mins.
Then restarted and it ran into issues.
First, I got the Apple logo and a prohibitory symbol - flashing between the two.
I turned it off and took out all the other drives, bar the OS drive.
Turned it on, then got the load up screen which hung a few times, then rebooted a few times, then the black screen.
Turned it off and restarted, and it loaded up, I typed my password and rebooted. That happened twice, followed by black screen.
Then I turned it off. Turned on again and it booted up normally.
The NB D was 77c and NB HS is 65c after almost 30 mins.
I saved the crash report.
I restarted, and it booted up normally and has been on for 40 mins. Same temperature rates as above.
Thanks.

 

[tsialex]

Same problem. I'd test a known working CPU tray, to be sure that this CPU tray is toast.

 

[cakey]

Same problem. I'd test a known working CPU tray, to be sure that this CPU tray is toast.

I had a feeling you were going to say that.
If I was to buy a CPU tray, I would prefer getting the same as mine, in case it needed to be replaced. But, looking at the prices of the same CPU tray I have, it may be better replacing the whole computer and selling my computer.

 

[tsialex]

Sure, but if you have a little patience and search everyday the auction sites, call your nearby e-recyclers/etc, you'll probably gonna find a whole dual CPU mid-2010 Mac Pro on the cheap, then you will need to buy just a single CPU tray to make a spare.

Get the best parts of each Mac Pro to make a very good one for you and then you have another one to sell and recoup a big chunk of the expenses.

 

[cakey]

It took a few months, but I managed to pick up a 2nd hand 5,1 for a very reasonable price. The whole computer was cheaper than the price of the trays for sale.
The specs aren't as good, but everything seems to run fine.
I swapped the trays around and have run both computers (playing videos online) for 15 hours. Neither of them have crashed so far.
As I am trying to figure out what is wrong here, is there anything else I could do to see if there are any issues, bar wait for a crash?
Thanks.