Who does repair work on old Kenwood receivers?

I pulled out my 1975 Kenwood KR 3600 receiver for the first time in about 25 years or so and was amazed that it turned right on. It is very dusty and is missing one of the controls knobs on the front panel. Who and where would get this up to spec's ????? This was my first piece of audio equipment, so there is some nastalgia here ??? Thanks