I have an R610 with a sick Delta PS. It cycles on/off every couple seconds. So as to not beat up on the motherboard I have plugged the supply into an Ultra ULT31553 PS tester. The supply behaves the same with the tester. I purchased a replacement supply to be able to get the R610 back on the air. Beware of aftermarket 20/24 supplies as their 6 pin connector is +12 and ground where as the Delta supply 6 pin connector is +3.3, +12 and ground. I have tried to analyze the circuit and figure what is wrong, so far no luck. I am an old school service engineer and would rather repair than throw away. If there is documentation and/or schematics out there I sure would like to get my hands on them.