Fisher power amp out CA-270

A semiconductor amp should not care about lack of load. Driving it into an open circuit should not cause damage. On the other hand, driving it into too low an impedance, is an issue. If you have been fidling with the speaker connections and impedance selection, you may have inadvertently whacked a short across it. If you are lucky, it might have just knocked out an output fuse. Many amps from 20 years ago had fuses in this position. Sadly modern ones don't.

Check first for blown fuses, and if you find any, make sure that you replace with like for like ie not just the fusing rating, but also the type, F or T. As far as the speakers go, an easy way to do at least a basic electrical check is to just connect a 1.5 v dry cell across each one in turn, both ways round. The cone should move forwards and backwards by an even amount, and produce a nice clean thump sound. Alternatively, use a multimeter on its low ohms range. On this range, it will supply enough current to the speaker, to hear a thump.

Arfa

On Fri, 22 Dec 2006 10:56:30 -0500, DanFXR Has Frothed:

Could be the switch. Manipulate it between settings several times while the amp is off and see if the channel comes back.