I used to repair ultrasonic cleaners back in the 70's.
The most common problem was the transducers becoming partially unglued
from the tank. I always assumed stuff had been dropped into the tanks,
but perhaps the ultrasonic energy caused it.
I used to pry the transducers off the tanks and then glue them back on
with a silver-loaded epoxy. This usually worked and was quicker and
cheaper than a new tank assembly.
I would usually test the generators by substitution with a good unit,
something you can't do. If they needed repair I would run them with a
resistive dummy load, but I can't remember what value it was.



In message .com,
Nortonfan writes
I'm attempting to bring my Bulova model TR250 ultrasonic watchmaster
cleaner back into service. I have found two rectifier diodes blown,
along with the circuit protection fuse. The wafer transducer is epoxied
to the the tank, and I am not sure how to go about testing for
problems. It appears to be solidly mounted to the tank with no visible
fractures to the epoxy joint. However, I suspect there is a problem
with it, as it has lost its cleaning abilities. This model seems t
have been made in the mid '80s.

Thanks for your help!


--
Neil J. Harris