Honestly I don't even know where to begin with this one, so if it's a bit disjointed I apologise. I have a server built in a SuperMicro SC847 chassis - X9SCM-F, E3-1230, 32GB, 2x X520, LSI RAID, 36x 3TB and 8x 300GB SSD, so it's heavy! It's worked fine for ... six months at a guess? I just instrumented it (new grafana deployment) and wondered why the fans were showing 0 RPM, so I shut it down to check (turns out all the fans are on the backplanes, not the mainboard). Oh well, that's easy. Now it won't power up. Well - to be specific. It won't power up in the rack. All I did was disconnect everything and slide it out so I could remove the top and check the fans, then reassemble and slide it in. The orange "has power" LED on each PSU is lit (goes green on server powerup). I swapped the power cables, and the rack PDU to which the server is connected, no change. I swapped power supplies from the "spare" chassis. Eventually I decided I couldn't fix it in situ so I pulled it and placed it on the dining table (because where else). Powered up first go. Crap. OK that's fine, I'm a masochist. Disconnected it all. Moved back to the rack in the garage. Installed. Nope. Not a freaking thing. Swapped power again. Nope. Pulled it out of the rack and tried running it in the garage but outside the rack. No go. Ran the power from the dining room out to the garage, used the same cords and power board that work in the dining room. Not a damn peep. Brought it inside again and connected it on the dining table. Powered up perfectly and it's humming away (literally, I forgot how loud it can be) on the dining table. Which sucks when you don't have the 10Gb network inside the house, just the rack/garage, and it is the storage for 47 VMs and the media for Plex etc. (I could run some house ports at 10Gb, but I don't have 10GBaseT NICs - I'm all SFP+). 47 VMs and media streaming over 1Gbps is a bit of a stretch. So ... ideas? Anything? I'm completely flummoxed as are several people I've discussed it with. Edit: There's a stack of things running just fine in that same rack off the same base PDU - a pair of C6100 chassis, LB4M, a pair of PowerConnect 8100's, two whitebox rack servers (DCs). So it's not JUST the one thing in the rack.