This could go on a long ways. Onne of the best troubleshooters on anything electro me chanical is a tv repair man by trade, never been to school for that either. Only formal training he ever had was a year or 2 hs auto shop. I know a couple 3 legit masters in several trades also. They trouble shoot with,,, well most of them, etc and when I wanna know I call the tv guy, its got a failed hi miint on a secondary,,, whatever or a resistor on a board of electrically reversable with 3 relays , my master bud bout passes out,,, the tv man is grumpy and complains a little at first but puts his finger on it.