I got a 2400W server psu along with a 750W psu for a 12GPU rig.
When my rig dies for some reason, does not happen too often, but when it does, the server PSU keeps the GPU's running.
Im looking for a way to get around this problem, any ideas?
depends on how good you are at diy electronics.
one way is you can use a relay to control the 2400. a 12v output on the 750 powers a relay that the 2400 is plugged into. but relays that control that amount of power may be hard to find? you would want something that can switch 3000 watts at 240v (i assume the server relay is on 240v). so 15+ amp 240v relay with a 12 volt coil would do it. make sure you use a big safety margin.
another way is maybe the server psu breakout board has an on off toggle switch? much easier to use that as its low power. same deal relay powered by the 750 opens/closes the power switch on the breakout board (NOT the switch on the server psu itself). that can be a much lower powered relay as the switch on a breakout board hardly handles any power. but check with the maker of the breakout board. a slightly modified add2psu style relay might be able to be used it this case. the add2psu would connect to the server psu breakoutboard switch contacts.