My 1986 Trans Am has the factory performance sound with the rear subwoofers. Apparently the remote mounted amplifier under the dash on the passenger side is dead. I understand that this is a common problem. The radio and cassette system plays, and it sounds Ok, however the amplifier is not working. The amplifier power switch lights up, but the gain slider switch has no effect. Are there any stereo service centers that offer repairs or direct replacement amplifiers? And no, I don't want an aftermarket system. The car is a trailer/garage queen, and I have this OCD hang-up thing going on about keeping it original. Thanks in advance.