All well designed amplifiers will have fuses, saftey resistors, and other parts that protect the circuit itself and the load connected to it from being damaged, should a malfuction occur.
I once had an ampllifier that was changing inputs by itself, shutting on/off randomly, and the output would be clear as day somtimes; otherwise, it would just keep failing. When this stage of failure is reached, many things could be wrong and repair costs will be higher.