Some insert lamps are on all the time and some are never on (they are not broken). When I look at the lamp driver board, the transistors in question even look broken (see image).
Is it as simple as this? I replace every transistor where there is a problem.
Should I measure the transistors first, and if so, do I check the resistance or use the diode test? Is it ok to do it while the board is still connected?
Could other components be broken? Can there be another underlying problem? How can so many transistors be broken at the same time?