Chosen Solution
After doing some analysis, i think i know why it’s shutting down, i’m just not sure how to fix it. I suspected my system was overheating, so I installed software that listed temperatures of all the components. Ambient temperature was 80 degrees Fahrenheit, while most components themselves hovered a little above 100-120 degrees Fahrenheit range, EXCEPT my Power Supply - it was at 219 degrees Fahrenheit. I installed fan control software to get fan readings/settings of fans. The PSU fan was 0 rpms! All other fans were around 800-1000 rpms. When i tried to manually set rpms on PSU fan, the software error-ed, and said it couldn’t control this fan. So do i have a bad fan? I’ve tried unplugging all cords, to reset pram, and fan still malfunctions. I searched the internet for mac pro fan, but i’m only finding fans that will fit the CPU locations. I have a ma pro 4,1 (early 2009). Any advice?
FAN IS WORKING!! Ok, I took the PSU out - 2.5mm hex didn’t work for screws, I used a 3/32 with ball end to remove screws. I think I know why there is no mention of PSU fan in the iFixit manual, because it is such a hassel. It is attached to a piece of metal which cannot be removed (see pic1.jpg). It’s attached by some rubber fasteners (see pic2.jpg). Once I loosened fan, I realized the wire goes behind the board, and routes to front near the PCIe Fan (see pic3.jpg). In order to disconnect this cable, I had to remove the PCIe fan. After I disconnected PSU Fan cable, I used my datavac duster (http://a.co/bJ0zQUz) - very powerful, on all components (PSU, PSU FAN connectors on wire and board), and went ahead and did the entire computer (although it was already clean). I plugged everything back in, said a prayer, and booted it up. THE FAN HAD A CONSTANT SPIN. Afterwards, I installed the fan software (https://www.crystalidea.com/macs-fan-con…) and it was able to read the RPMs (see pic4.jpg) and it will even let me customize the speed. Before it would error when tried to customize, and it was grayed out. Thank goodness. Thanks everyone for the help and suggestions!!
Yes, your temps are dangerously high and should be rectified as fast as possible! If your PSU is heating to over 100 degrees C, you shouldn’t turn it on until it’s fixed, it may be a fire risk at this point. If you feel confidant remove it, check for blockage, if this MAC has never been serviced it could be caked with dust and isn’t allowing cool air flow. Let me know if this helps, or if you have any other questions.
I looked back over this question as I have both a 2008 3,1 & 2009 4,1 covered to a 5,1. The 2009 is actually a second generation and we don’t have a guide for it so the link Conor gave is incorrect.
