Check the two 10 ampere fuses at the bottom of the power board where the mains filter plugs into. They are the multi striped units about 1/2" long that snap into the chassis. There is a fuse for both sides of the mains (hot and neutral) Check the fuses for continuity with an ohm meter. Should read .1 ohm or less. Replaced one of the fuses (read open on the meter) and the set came back to life.