I have just finished building a new PC and am having a strange issue with my 1200 P2 (around 4 years old). As soon as I flip the power switch on the PSU the PSU fan starts spinning, once i turn the PC on the fan goes off (Eco mode is on, if i turn it off the fan spins) and seemingly operates normally. When i shut down the PC from windows the PSU fan will stay spinning. It will only stop if I flick the switch on the PSU to off. I have disconnected the 24 pin from the motherboard and used the jumper and everything operated normally. I was using cable extensions, though i tried with no extension and the same behaviour occured. The PC appears to be running fine, no strange behaviour)
I do have another PSU though due to the cabling set-up it is a major effort to unplug the P2. Am i able to leave all the cables except the 24 pin plugged into the P2 and components (no power going into the P2) and just plug the 24 pin cable from my spare PSU into the motherboard to see if it shows the same behaviour when i flick the PSU switch or would this damage things?
Components are : 3900x, Gigabyte master x570, 2080ti, 32gb ram, 2 nvme drives, 1 hdd, 2 D5 pumps, Aquaero 6 lt, Quadro.
Hope the post makes sense.