Hi One thought. If it uses transformers anywhere, connected to the AC ( even switchers often do this for initial voltages ), you need to put a MOV on the input leads. The problem is ( and I've actually seen this ) that when you cut the AC, the core holds some energy. Since it can't pass this to the input leads ( you know, that 90 degree phase thing ), it causes the voltage to spike on the secondaries. Many negative regulators could not handle the spike. Second thought. If it is using switchers, make sure you are providing the right AC voltage. Many of the older switchers would actually run on 120V when setup for 220V, for a short time. They would eventually blow in a minute or so. The problem is that with the lower voltage, the switcher would be running too long a duty cycle. This would smoke the transistor because there would either be some overlap or the cores would saturate. In either case, it would blow the supply. Dwight