In message <027f01ca8215$c2e2fba0$184065da@ivp3ghz>, ivp writes >>> from a good refit, clean and resolder >>> >Generally it's put together solidly but only those transistors are hard >to get at. After a little more research into how ultrasonic welders work >these may be less like audio power types and perhaps more like high- >voltage TV or monitor line output transistors Your description made me think BU208 which is a TO-3 TV line output transistor, it was sourced from SGS amongst many others and I've seen it used in ultrasonic cleaners. > >Yes, I have been looking at the caps. Both the electrolytics and non- >polarised are all the old-style pig-tail mount, very large physically for >their capacity. I note in the vintage radio articles in electronics mags >that the capacitors are the first suspects and the components most >likely to be replaced routinely Seconded, highly likely to be lower value and higher ESR than they should be after that time. Worth checking resistors as well, high value resistors tend to get higher in value if used near their rating. Reseating the socketed chips would be worthwhile too. > -- Clint Sharp -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist