Receiver still works as long as amplifier board is disconnected from power supply

 

It looks like an inductor to me. Possibly 22mH. What is this from (make & model)?

 

The 220 parts (Lx) are 22 uH inductors, and look to be of the "shielded drum" type. Current rating will match or slightly exceed the expected current of the amplifier's load (speaker) at full power. Unless they have become open circuited it's unlikely they contribute to the problem. Wouldn't surprise me if one of the amplifier chips blew an output transistor, which now overloads (shorts out?) a power feed.