My 2002 A6 Avant has suddenly developed what I am coming to realize is a somewhat common audio problem. Car is equipped with the Bose Symphony radio which has worked perfectly well since its replacement, under extended warranty, about four years ago. At that time, the unit simply would not power up under any circumstances, and I believe that the "head" unit was the only thing replaced. (Lost a great Johnny Cash CD in that one...)

Two weeks ago I removed the battery for unrelated issues and upon replacing it, the radio has gone on strike. It powers up, displays "BOSE" for a few seconds and then shows the current radio station, AND the legend "RDS OFF". Pushing the RDS button clears that legend but no sound is to be had regardless of input selected or volume setting. No "SAFE" indication.

I have tried removing the fuse for the radio (#43) for several minutes with no success. There are some "soft" mechanical sounds emanating from the dashboard area upon replacing that fuse but no change to the radio's output. I have disconnected the negative cable from the battery for ten to fifteen minutes and then re connecting it, but no dice.

Posters on another site have suggested a bad fuse at the sub-woofer amplifier unit in the rear, but I haven't been able to locate any such fuse, if it exists.

I am very comfortable with disassembling, trouble shooting and re-assembling almost anything mechanical, but much less so with electronic components where no apparent damage is visible.

I have watched the you tube video of removal of the radio which seems pretty straightforward once one has the appropriate tools, but I'm leery of pulling things apart without attempting to isolate problems first. Is there an easy way to determine if the radio is in fact outputting any audio at all to either the front speakers or the Bose box in the rear?

Any suggestions at all would be most appreciated, my wife is a radio junkie to put it mildly...