The frequency at which the Rockford t1500 1bdcp amplifier driver operates floats away

Hello! I have a problem with the t1500 1bdcp amplifier. At low volume there is constant noise after the amplifier warms up. It looks like the problem is in the throttle output ring. it seems to have lost inductance. can you please send me the circuit diagram of this amplifier? I want to replace the ring and throttle, but I don’t know which one. The frequency at which the driver operates disappears; it is not clear why this happens. I checked all the little things, everything is fine. There is a suspicion that the ring on the output choke has lost its inductance due to time and heat. The amp also gets very hot even when not playing.