Posted by Colin Heseltine on 15/03/2020 17:11:00:
Reviving an old thread. My Ultrasonic cleaner has died. It powers on okay, heats up okay, appears to start on the timer and switches off again after appropriate time but I do not get the ZiZiZi noise it used to emit. No bubbles or cleaning.
I came across this thread whilst searching for repairing said item. Took the bottom of to check for problems and can see no issues. Checked all 6 fuses are okay, can see no melted or blown bits, all wires connected and good. It is model with 4 transducers.
I also had the same problem on my PS 30A (the version with 3 transducers) and I'm trying to solve the problem. At the moment I have found some problems in the secondary pcb

fuse F1 blown and transistor Q1 defective.
Moreover I also found damage on one of the three piezolectric transducers

However I think there may be some other problem because I tried to disconnect the secondary IPC (which only controls the damaged transducer) but it doesn't work either.
someone suggested to me to test the resistances of the piezoelectric transducers