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boardjunkie
 
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Default SWR SM-900 bass head broken wiring

I had this SM-900 rack bass head come in for repair (fan failed and
caused a meltdown) and someone had already been in there mucking around
with it. Since there are no connectors for the pwr amp modules, the
previous "tech" has broken off a couple of wires from the pcb. The
service manual details one side of the output section (its a
stereo/biamp head) but not the other, and they're not identical. There
are 2 20awg brown wires that have been torn loose. One comes from the
AC leg of the main bridge rectifier and connects to the corner of one
output pcb, which is shown in the schemo and has been repaired. The
other brown wire is attached at the opposite pwr amp pcb and connects
(I assume) to the other side amp pcb. Anyone worked on this unit and
know where this wire is going? I assume it would be after the rectifier
diode at the filter cap and they're just jumping voltage to the other
amp pcb but I want to be sure so I don't have a smokeshow after I just
rebuilt the damn thing.

The techs at Fender were of *no* help whatsoever......just tried to
talk me into sending it out to them. No thanks.....I'm not eating the
time I already have into it.

Also....anyone know the idle current for the output amps and where they
check it at?

Thanks
Travis