My machinist friend asked me if I can repair this board for him. I am capable of testing, sourcing and replacing individual parts but I am working blind. All I have is a dead control board containing bunch of LF347 op amps, their accompanying discrete components, some driver transistors and one IXYS power transistor which I was told that is what usually blows. I tested this transistor independently by driving it with a signal generator and it the scope tells me that it is ok. I do not have the schematic and the entire board is covered in thick layer of conformal coating which makes it very difficult to determine the fault. Does anyone know what normally goes bad with these boards?
Machine - Hobart Champ 2060 Board #198203