"Gareth Magennis" wrote in message
...


"Arfa Daily" wrote in message news
Anybody by any remote chance have a schematic copy for a C - Audio RA 1001
slave amp ? Drawn a blank from all the usual places.

Looks as though it has been stored somewhere cold and damp, although dry
enough now. Basically, it won't come out of 'protect' although there seems
to be nothing wrong fundamentally with either channel. Both channels have
good output, with no DC offset, as far as the output relays. There is
another relay over at the mains input side of things that looks like it
shorts a bloody great resistor, so inrush limiting I guess. All three
relays
remain stubbornly off, and the protect light stays on. I can't read any
volts at any of the three relay coils, and none of the pins appears to be
grounded, so they are not high-side switched. So may be something as
simple
as a missing rail, but hard to follow print around as it's double sided,
and
fairly crowded ...

Arfa




One corroded track I found was actually underneath one of the relays!

You could be right and it might just be the low voltage supply for the
protect/relays.
If the inrush relay doesn't click in, the output relays won't either,
otherwise the inrush resistor would go bang once the amp delivered any
power.

Gareth.


Pretty much as I was figuring then. I'm sure it will be a simple problem
when I get to the bottom of it. Just depends how much time the owner is
prepared to pay for ...

If you have any schematics that are at least similar, it would be
appreciated. Most of these amp manufacturers don't reinvent the wheel, and
the relay circuitry is quite likely to be similar between models

TIA

Arfa