Ultrasonic Cleaner Very Weak Cavitation - What causes this

That doesn't spell "very weak" to me, but maybe I'm just clueless. The innards of these cleaners have two features that can result in lower output: (1) mechanical coupling of ceramic ultrasound transducer to the tank is through a high-tech glue blob, so if that glue cracks, the transducer vibrates 'free'. (2) Often the oscillator has a tuned circuit that acts to impedance- couple the transducer. Tuning can change over time.

I've used some hotmelt adhesives for ultrasound, but I presume the transducer coupling is epoxy-like, so it can't be easily fixed. Inspect and if it's bad, consider rebuilding options. If it's the transmatch network, I've seen adjustment options (use a PLASTIC driver to turn the ferrite screw); an AC current meter will indicate extra power drain if you are increasing the power transfer to the water that way.

The transducers can also crack.

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Thanks, I did another foil test last night and I do think this unit is probably working properly. I saw about 20-30 small perforations form over a 10 minute cleaning cycle. Maybe I missed them the first time because they are very tiny. Once I hold the foil to a bright light they become obvious.

The transducer ohms out as infinity and looks solidly attached to the tank and I see no cracks or other damage.

I'll take another look tonight but I don't recall seeing any tuning adjustment on the circuit board.

What was the thickness of Al foil, as measured on a micrometer ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

on

It's freezer foil and it measures .0015"