There are many failure modes for a power amp. Presumably you're referring to an audio power amp, though you didn't specify. You also don't indicate what "being difficult to work with" means. Troubleshooting can also depend on whether the amp uses tubes only, transistors only, or is a hybrid which can use both. You really need to provide more info and describe what "being difficult to work with" means and describe in detail what you're experiencing with the amplifier.