I'm with Kwayde on CLEANING ALL CONTROLS 1st. You NEVER get rid of ALL the corrosion or crap on the controls. And momentary switching from AUX to another source clearing it up is a BIG CLUE. leave it on one source and don't exercise it, and you get corrosion buildup. Corrosion in this case includes dust, airborne contaminants, ozone, Dissimilar metal cathodic wastage (not common but it does happen), and just plain time and air. But you can minimize it. DON'T just spray and call it done. Normal contact cleaners just blow off the Surface stuff and leave you with Clean corrosion. DeOxit softens the Surface junk, so it can be scraped off during exercise of the control within 15-20 minutes. I tend to be quite liberal with D-5. Spray, walk away for 1 hour to let it work at breaking down the corrosion bond, then re-spray and exercise the hell out out of controls. Flush area with CRC QD Electronics cleaner, then apply De-Oxit Faderlube or Shield to actual control.
You can Spray DeOxit on/in the controls. Let it work 15 minutes or so. THEN EXERCISE THEM(IN-OUT, UP-DOWN, ROTATE LOCK TO LOCK, BACK AND FORTH.....40-50 times VIGOROUSLY Friction with DeOxit scrubs the environmental crap off the contact surface, leaving a shiny strip the contact follows. If you really want to fire up your OCD, Dissassemble each control and get ALL surfaces bright and shiny and re-assemble. RULE OUT THE EASY STUFF 1st. Cleaning controls needs to be a yearly thing with the x2x and x3x series of PIONEER receivers.
Relay's have a silver coating on the contact surface. They can and do get pitted from arcing during opening and closing. DeOxit and narrow strips of plain white paper do a decent job of cleaning the surface carbon but doesn't do anything for the pitting. Cleaning is a short term solution as you'll be replacing it within a year.
