I have to repair an optoma ust projector that not light up, at all. It's try 3 time that lamp error turn on. I'm focusing to the ballast, it's a philips but no schematic, nothing eveng close. On the input I have 380V, no short on mosfet or vast majority of the power silicon, There is a stepdown that produce 12V and it seems to word, there is a step down that provide voltage to the output bridge. It's an odd one because it high side driven with a nmos, it use the high side part of an fan7380 do drive it. This part seems to work because after this stepdown voltare rise breafly when it try to start. Output mosfet get warm during the 3 try. I think that the ignite part not work but I can't figure it out how it produce the voltage spyke needed. Thanks.
PS: i did try 2 lamp, the one that did work and a new compatile (it use a philips bulb).