No Sound from Radio

The radio in my '92 325i suddenly went silent on all four speakers, but appeared to be working fine in all other respects (display lights, tuning appears to work fine, for example). Figuring that the power amp in the radio was shot, I bought and installed an aftermarket radio (Kenwood 516S). Guess what - still no audio, though everything else seems fine. Any ideas? Could a short in one of the speakers bring down all audio outputs? Is there some fuse I should know about? Do the speaker wires go directly from the radio to the speakers?

Thanx -
Rob:(

Check the wiring harness in the back of the radio. Do you have the regular or HK radio?

Thanks for your reply. What is the "HK" designation you referred to?
I'm not familiar with it. The radio is a stock Blaupunkt radio/cassette that came with the car.

Am not sure what to check in the wiring harness that would affect all four channels apart from power. However, the power leads seem fine, given that all the other functions (tuner, lights, etc), seem to be working.

Somone I spoke to about this suggested there might be a separate amp located somewhere in the car. Is this likely, and where would I find it if there were. When I installed the Kenwood replacement, I noticed that the Kenwood harness has a "power amp control" wire that didn't seem to correspond to anything in the BMW adapter harness, so I left it unconnected. Could this be the problem?

As a general question, how would the Kenwood know whether there is a separate amp in the car or not? Would this be the function of the power amp control wire? Can the radio be used in configurations in which there is an amp as well as those in which the speakers are driven directly from the radio? Thanks again.

I agree that there is probibly an amp somewhere else in the car that is not getting power. You might check under the drivers or passengers seat, or in the trunk. I had a similer problem.

Turns out the power amp was indeed in the trunk (left side behind trim), and had corrosion on the outside and possibly the inside owing to a leak.
Unfortunately, I can't bypass it easily because it contains crossover circuitry required by the car's speakers.