MP 1,1-5,1 Mac Pro CPU upgrade trouble

[Taipan]

Hi!

Due to the sound and sleep issues with my Mac Pro 4,1 (flashed to 5,1) I decided to do another CPU upgrade (dual X5570 to dual X5690). I had already upgraded the CPUs on the same machine years ago from E5520 (I think).
During the upgrade I notice I had the common Northbridge heatsink problem, so I fixed it with screws.

I installed CPU A first and tried to start the machine up with only that CPU, as many people recommend. but there is no chime and I don‘t see a single LED light up on the CPU tray. The fans do rev up, but not to full speed, but to what seems like the usual behaviour. No image on the display, of course.

I guess since there is no life sign from the CPU tray at all, I‘m probably in trouble, right? Any ideas how to troubleshoot this? Would it make sense test the tray without any CPU installed at all?

Any help would be greatly appreciated.
Thank you very much!

Backplane seems OK according to diagnostic LED. But I just noticed two pins of the currently empty CPU socket B are bent. No idea how that could have happened. I hope I can somehow get them in place again.

 

[Taipan]

Seems the new CPUs are dead. Tested them individually several times, to no avail. Popped in one of the old ones, worked right away. So I installed the second old one as well, but then it‘s dead again. Probably the pins of the second socket are still not aligned correctly.
Edit: The pins look OK‘ish now, but no dice when the second CPU is installed. Another question (although the new CPUs are not my primary problem anymore): I ordered them delidded, they came with the lid included. The top surface of the CPUs has no writing at all and is completely scratched. Does that happen during the delidding process? I would have expected them to look pretty much pristine under the lid (I don’t know whether they had been used before in a delidded state, though).

 

[Taipan]

I have now tried the original CPUs the machine came with. Both work in slot A (after several tries). When I start with both inserted, the machine boots, fans rev up, but rev down again when it gets to the desktop. The OS only recognizes one CPU, though. I thought with only one CPU the fans should run at full speed (they do if only one is inserted). Is there anything I can deduce from this?

 

[Taipan]

It works now with the new CPUs! I think my main mistake was to try to approach it systematically. It‘s a computer, you just have to do the same thing over and over again until it works. Einstein was so wrong!
Sorry for the pointless thread!