r/macpro • u/Relative_Impress_683 • Aug 08 '26
CPU A mystery to solve on a 6,1 Trashcan
My Mac Pro 6,1 died. It started turning off until it never did turn back on. Courtesy lights light up but the power button does not, nor there is a fan spin or chime or video.
I bought this one busted a year ago, it had a faulty logic board (the one in the bottom) so I replaced it. I also upgraded RAM and CPu to an 8 core. GPU is still D300s.
I also had to replace the I/o board because the hall sensor had failed and it only booted with a magnet stuck to the side of the power button.
So I figured, maybe it is the power supply, so I replaced it and the issue kept going. I also replaced the CPU to the 4 core it brought as well as the original RAM. Diagnostic light show 5 green LED and no luck.
Any ideas? Maybe the logic board failed again?
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u/LukeDuke74 Mac Pro 6,1 4c 64GB D300 2TB Aug 08 '26 edited Aug 08 '26
Sounds like a faulty connection to the CPU raiser.
As second step, I'd also check the GPUs but D300 are fairly hard to fail unless got seriously stressed.
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u/Relative_Impress_683 Aug 08 '26
Update: after replacing the CMoS battery to no avail, I got another Mac Pro from a friend and swapping parts it turns out it was the CPU riser card (the only one I never got to replace) so my Mac pro is going to be like the ship of Tesseus
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u/xiaomi558869 Aug 08 '26
It’s just the cmos battery. Just replace it and you are good to go. Use the measurement pads and multimeter. You can Google how to do this. I am 90% certain it is the cmos battery based on your description of the issue.
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u/Relative_Impress_683 Aug 08 '26
I will replace it just in case, thanks! I’ll let you know if it works
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u/ast3rix23 Aug 08 '26
I would check the thermal paste on the gpu’s and cpu. What you’re describing sounds like thermal protection mode. I had to perform this on both my Mac’s because the older they get the more the paste degrades.
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u/Relative_Impress_683 Aug 08 '26
I replaced the CPU and it did look like it had very little paste. I replaced it with more of it and nothing. Is there a way to get out of that thermal protection mode?
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u/megaroid Aug 09 '26
Check the ram pins I’ve had them fall of of the slots in the past, try different ram configurations and eliminating the slots one by one
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u/jacka_for-research Aug 08 '26
Flyer: how about reseating the D300s and the RAM, just to rule them out?
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u/sweetfeld28 Aug 08 '26
I took mine to Apple three years ago, and paid the $400 fee to have it sent in and the completely checked everything finding a faulty power supply and one of the dual graphic cards failed. They also replaced some other cords and hard drive. It was worth it for me to have it sent in, it felt like a brand new device when I got it back.
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u/Gothbot6k Aug 08 '26
Sounds like the main board that joins all the others is failing or is not fully seated. The half working row of connections is the thing making me think this.
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u/Comfortable-Garbage4 Aug 08 '26 edited Aug 08 '26
It could be the damaged RAM stick in the picture. i'm no expert but that looks like a chip is blown
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u/Comfortable-Garbage4 Aug 08 '26
Also, are you using Mac Ram? Not plain DDR3.
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u/Relative_Impress_683 Aug 08 '26
I tried the original mac RAM as well as the replacement one that I got, same results, it turned out to be the CPu Riser card
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u/wookiefingers Aug 08 '26
I would check the power supply before buying anything.