Yeah look at the picture here and I circled the output IC chip. It is bolted down to what we refer to as a heat sink, which helps the component expel heat through the metal. Look on that chip that is bolted down and try to read what it says. The diode is in question too if it is burnt as well as the trace of copper on the board that it connects to.
Edit and ADD... The IC power opamp should look identical or similar to this...
Edit and ADD... The IC power opamp should look identical or similar to this...