Power Supply, Overheating components, Voltages Out Of Spec.
The power supply in my Marantz Receiver is way out of spec, I need to figure out why, at the 20v side iam getting 30 volts at the 24 volt side iam getting 28 volts, this is causing a mosfet to cook and it is also causing 4 transistors to cook, ive replaced them, it works but they get scary hot, I replaced 2 ceramic disc caps on the psu along with a resistor, This model is a exact twin of the Carver 895 receiver, Please help. This IS one a regular 120 volt ac line.
Any chance of finding a schematic?
There would not be a 110v/220v switch that might be in the wrong position? (I had to ask).
I am guessing you are not hearing a 60Hz hum, so it is probably not a filter cap. See if there is a reference zener (looks like a diode). It may be labeled CRx or ZNx, VRx or Vrefx. These are available in many values, but are only stable in certain values (that's Physics for you - only partly stable). If the reference is bad the output would only go a few volts high or low which should produce that symptom.