Time for a something a little different, I've had a 30L no name Chinese Ultrasonic cleaner for a couple of years now and it does a good job of cleaning arcade boards. The problem is it isn't great when it comes to cleaning the odd small items here and there. As it takes a few hours to heat up the water so I was on the look out for something much smaller for these cleaning jobs.
I also wanted something better quality and I see a lot of people saying Crest is the best, the problem with the best is it's also stupidly expensive. So I was on the look out for an old and broken Crest to get it as cheap as possible, this was actually advertised as 'untested' but that's usually code for broken.
The first problem I noticed right away was that the tank was no longer properly attached to the chassis. Originally it was attached with a clear silicone sealant. I bought a tube from amazon and reattached it.
Leaving that a few days to dry and then filling the tank (never run these dry) it powered on and the heater works but turning the right knob to start the cleaner did nothing.
With the board out there isn't too much going on with it, it's a lot more basic than newer Crest models. I think this one is around 20 years old, but basic is good as there's less to go wrong.
At first I thought the IRG4BC30 transistors were bad as neither of my testers knew what to make of them and said they were two capacitors. I ordered some new ones from ebay but those tested the same so that wasn't the issue.
After digging a bit deeper I found that the resistor at R1 (10K) was open, it's a wire wound 2W resistor, luckily ebay to the rescue again as one seller had a perfect replacement.
I am not actually sure if it's 1W or 2W as the original isn't marked and the replacement didn't say either but the original is the exact same size as the new one and it works now so that's good enough for me.
Repair complete.
