no audio after battery died/recharged

Thanks for the thoughtful insight, friend. I appreciate your interest in helping me solve this problem. I only posted the "Cliff Notes" version of what I've found. I had partially dismantled the amp earlier, and not finding any fuses apparent, I put it back together again. At this point, I'll take your advice and completely dismantle it to see if they've hidden a fuse somewhere in the guts of it. There doesn't seem to be a wire that actually turns on the amp. As I've mentioned, there are a total of three wires into/out of the amp that are either 12V constant, or Acc-switched. All three have voltage. All the others are either signal in or out of the amp, and they all have voltage, too. I honestly believe the problem is within the BCM, primarily because the steering wheel-mounted radio controls are not operational, and that's where these functions get their instructions. I thought I'd try a replacement radio since that seems to be the likely problem with the 6-CD changer, but I'm not particularly hopeful.Ray

I'm happy to report that this problem has finally been resolved. It turned out to be a faulty radio after all. I replaced the original with another RBP unit from a salvage yard, and everything works again. Not only does the system have sound again, but it also communicates with the 6-disc changer, and the steering wheel-mounted radio controls function again, also. I'm guessing that the problem was in the Aux. circuitry in the original radio. Whatever it was, I'm delighted. Hope this may help someone who experiences this problem in the future. Thanks to everyone who helped me sort it out! Ray