If you're happy to have a look inside the amplifier you can disconnect it from the mains (important bit), then take the lid off and have a look. It doesn't hurt to look for components that are obviously at fault, (burnt, bits missing, no longer connected to the board etc). Be advised there will be some charge in the capacitors still so don't go poking around too much. If you find something clearly not right, if you have the tools and skills then you could replace the component, or send it for repair. Be advised though that sometimes a fault elsewhere may cause a component to fail.
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If you're happy to have a look inside the amplifier you can disconnect it from the mains (important bit), then take the lid off and have a look. It doesn't hurt to look for components that are obviously at fault, (burnt, bits missing, no longer connected to the board etc). Be advised there will be some charge in the capacitors still so don't go poking around too much.
If you find something clearly not right, if you have the tools and skills then you could replace the component, or send it for repair. Be advised though that sometimes a fault elsewhere may cause a component to fail.