Yamaha Natural Sound Stereo Receiver RX-750
I have a Yamaha Natural Sound Stereo Receiver RX-750 (purchased maybe around 1992-1993?). The input selector switch doesn't seem to be working properly. No matter which input I select, the sound is fuzzy and static-y. If I jiggle the knob or press and hold it in tightly, the sound will clear up, but often goes right back to fuzzy as soon as I remove my fingers. I have to keep playing with the knob until I finally get clear sound.
It has been suggested that I repair this using a contact cleaner. I successfully removed the cover from the stereo and the knob from the front. However, with those removed, I am in unfamiliar territory. Where do I squirt the contact cleaner? I am assuming it would be on the front side of the panel where the knob was removed, not on the back side inside the box. However, looking inside the hole where I took the knob off, I'm not sure where to start squirting. Should I just set the stereo up on end and squirt all over the stem? What is the proper technique for applying the cleaner? Here are photos:
If that is not the right approach, can this be repaired on a unit so old? Is this unit worth repairing? (It was quite expensive when I bought it.) Can I repair it myself if I get parts? How difficult? Inside and out, the unit looks immaculate.
Thanks so much!