I picked up a KA-9100 several months back and just got around to tinkering with it. Power light comes on, wait 10 sec and relay clicks but I'm getting no out put. Using my tablet for a music source, tried it on the AUX input and TAPE 1 input and still nothing. Tried moving all switches around and no luck. This unit has been sitting for several years at least. Anything I should be looking for first off that may be an easy fix ?