MP 1,1-5,1 External testing and assembly of Mac Pro 5,1 components?

[cinclodes]

I recently spent a lot of time trying to determine why the red OVTMP lights on the motherboard of a Mac Pro 5,1 came on and stayed on. I finally started zeroing in on the cause by connecting the motherboard and a power supply outside the computer. I plugged in the power cord, and the two red lights briefly flashed (as they should) but didn't stay on. I then assembled everything one piece at a time inside the computer and tested the red lights at each step. I finally determined that there was a problem with the power button. This experience made me wonder if it would make sense to do an external assembly of key components (more than just the motherboard and power supply) for testing. Perhaps one could build a type of jig that would hold the components -- something along the lines of a stand for an automobile engine. With such a set up, it might be possible to test components very quickly. It might be possible to build such a jig by cutting open an old Mac Pro case to allow direct access to the motherboard and other components and retaining a minimal number of mounting points.

 

[Macschrauber]

You can run the backplane, cpu board and psu outside the case without extra connections.

You can start the machine by shortening the pon pads.

Be very careful with the cpu board, especially with unplugging the board

 

[cinclodes]

You can run the backplane, cpu board and psu outside the case without extra connections.

You can start the machine by shortening the pon pads.

Be very careful with the cpu board, especially with unplugging the board

Thanks for providing that information and the photo. What are pon pads? What is the object just to the left of the graphics board? What kind of power button is that? This view helps me to visualize how to make a jig so that everything would be firmly mounted but could still be assembled quickly.

 

[Macschrauber]

If you have a spare broken / bend case you can butcher a half to mount the backplane. I have another test platform where I mounted standoffs. I have one 4,1 and one 5,1.

The object left to the gpu is part of the passive gpu cooler. This test rig is not to meant to run for hours as it has barely no cooling. For tests it is good enough. And if I have to test a longer period I place fans before the PSU and mount the PCI cooler. Southbridge is easy to kill with heat.

Pon pads: look at the diagnose button. there are solder pads for more buttons. The lowest one is for PowerOn. In electronics pon is a common term for power on.

In another test board I just soldered a switch button there.

Here I soldered a button with LED as I wanted to see the LED feedback for firmware unlock or memory faults.

Also I mounted a speaker, pon chime is an important diagnostic point.

Front panel board is not necessary, I had a spare one and wanted the front LED feedback.

 

[Macschrauber]

I knew there was a picture of the other test rig:

https://forums.macrumors.com/media/1190f894-ac0c-4a20-811c-b000f9691135-jpeg.826357/

 

[Macschrauber]

And another variant with more cooling, the summer setup

https://forums.macrumors.com/media/img_7105-copy-jpeg.747066/