Label says it's a GX-20M, no "R". O'drive switch is erratic in Overdrive. "Clean" is clean. But push switch in and sometimes it works, sometimes it cuts out completely. I believe I can replace it. Is it just pressed into the circuit board? Can I use a long flat screwdriver to remove it from the board? Thank you thank you. Do you sell new switches or do I go to our electronic parts store? Thanx again! ~pm~