You may be correct in evaulating that it may be a power supply filter Cap problem. The hum is not background hum but a very strong intense hum when the volume is turned up. I have no other external connections attached. It could also be a poor power supply connection. The KN7000 has never left home which makes it more of a problem in why this just happened. Hope I will be able to find a schematic of the KN7000 or a repair shop.

Thanks for your suggestions.