For 3 months now I have been trying to repair and error search Harman Kardon 220 sub power circuit board without any luck at all. Therefore I need some more electric minds and brains to solve this problem. I will attach the schematic below with the replaced components and voltage measurements.
Anyone have any idea whats going on?
The problem started with R23 burning out and recitifer bridge BR1 broken. It should be 35 VDC at DN4 and 3,3V DC at CN2.
It's a standard designation, going back pre-WWII - they would be C1 and C4 in series on this example - two rather than one, presumably to give voltage doubling on 120V mains.