So, the cheap ultrasonic cleaner wasn’t great from the start, it would take about five minutes to start up and when it did it was like a mouse fart. It worked for a while and was useful in it’s own way.
In the mean time I bought a larger capacity one and took this home for small jobs.
So now comes the time i need it to clean up some parts and it fails completely. Poop.
After taking it apart, it seems they are quite well made for the money, everything is shielded in the right places and ground points are well attached etc.
The ultrasonic transducer was toast, probably not that great from the start, but there you go. Also the resistors between the Base and Collector of the driver transistors were charcoal.
Which left me in a bit of a dilemma. What were the values? There was nothing on the internet and the company hadn’t lasted long enough to complain, let alone get any information from.
Then a thought popped into my head, I wonder if the other ultrasonic cleaner had a similar drive board in it. A week goes by and a trip to workshop one was overdue. To my relief, the other ultrasonic cleaner had the same board, and being a much later version had some modified and upgraded parts too.
The original resistors measured around the 30k mark, but looked like they started life in the 10k – 11k range as there was still one undamaged band left on one of them. The new beefier resistors were now 47k (five band jobbies, so yellow, violet, black, red, brown) (470×100 Ω ± 1%).
Anyway, checked everything else was ok, which it was, fitted some new resistors, and ordered a new transducer. The ones fitted in this range are 40khz @ 60watts. Just for reference.
So that’s how far I have gotten with this so far. I will have to wait for the new transducer to turn up and see how things go. Watch this space…