Grundig UC6620

The Grundig UC6620 ultrasonic cleaner is a 35W cheap device with a lot of failure points.

Faults I had to repair in my unit were:


 * A broken transducer
 * Shorted driver transistors (IRF830 500V NFET)
 * Shorted rectification diodes from the second discrete rectifier in the circuit, that's before the driver
 * An open 0.1 Ohm resistor coupling the rectified voltage over to the driver transistors. The damage was not visible!