Behringer B1800D pro, I have an active bass which won't power up on the board. There is 77v, 0v, 77v on the output rail. The DC rail is fine and I can't see any marks or unusual component faults. Any thoughts?
Audio Players & Recorders - Behringer - EUROLIVE B1800D PRO Active 18 In Sub
Answers & Comments
I had similar problem on mine It would try to power up and then cycle off and on.. I found Mosfets shorted.. T11 and T7 irfb4227 on P0981 pcb. This is a blue color pcb, not the power pcb, at least in mine. Also The Gate Drive IC Was bad irs20955 IC11. Failure occured in steps.. At first the unit was working, but only putting about about Half power. ( Looking at the design of this power amp, it looks like they have 2 parrallel Class D amps that drive the one speaker, so my guess is one side was still working until the FETS on the other side shorted causeing the Protection to kick in) Then it failed completely. I assume the gate Drive IC went out first, on the one side. then that caused the FETS to be on all the time and burnt them up as well. Just a guess.