Acoustic B20 wiring diagram
 

HI, I need the schematic for the B20, my husband can fix it if I had this. The fuse keeps blowing, he checked all he could without a diagram. If we unplug the transformer the fuse doesn't blow so it must be something on the circuit board. Hate to throw amp away, but not worth sending in to repair.
thanks a bunch. Any repair ideas would be great.

Check your capacitors. The two larger ones on mine went bad. You can tell they're bad if they're bulging on top.

Very likely the output devices are toast. they'll need to be replaced. the outputs will be obvious unless they are an integrated power amp chip.