What are the causes for a shorted output transistor?

Answer by  pryoplasm (444)

Could be many different things. Over time, certain electronic components just die, this happens. Another potential issue could be dust buildup leading to a problem with corrosion(rust) on the transistor.

Answer by  Oliviero (81)

For the most part, this has to do with the capacity going through them. It's not always easy to be able to tell what the real reason is, as it depends on the specific application. Consult the configuration schematic, and you'll likely see the logic behind it. Took me a few years to figure this out.

Answer by  Nikich133 (3)

output transistor has life span. another cause is joint near output transistor can be dry. also shortened flyback primari winding could be the problem