Blown Cap???What Else To Replace During Service???

Agreed with Ralph and the others on replacing electrolytics after a given age. I have had many successes with my gear with a magnifying class looking at caps for signs of heat, puffiness, or juice leaking out. Since I have a soldering iron and mouser account, I simply replace all the caps if one fails--not very expensive for me. I guess 20-30 years. My limited experience is that mouser and digi key are superb but mouser seems to stock more of the older type caps used by older devices.

The amp is 20 years old & ran Class A HOT so I figure some components must have been affected.I hope it's just something simple like a cap..

Look for burned areas on the circuit board, as well as burned-looking resistors. If a capacitor shorts out, it will often take other components with it.

Transistors can fail in milliseconds with no visible external signs. They will need to be tested for shorts and open circuits.

The amp is 20 years old & ran Class A HOT

@freediver Electrolytic caps don't like heat so 20 years does make them suspect.