It is an O.V.P. over voltage protection board. They were used with Defender style power supplies to keep the 5vdc circuit from pumping massive voltage down the 5vdc line in the event of a failure in the 5vdc circuit.
It is an O.V.P. over voltage protection board. They were used with Defender style power supplies to keep the 5vdc circuit from pumping massive voltage down the 5vdc line in the event of a failure in the 5vdc circuit.