Lexicon Mx200 Reverb Delay 1u Effects Processor "sound scrambles" Questions

No sound on a Roland model KR-4700. All 4 fuses inside are ok. Do you have an owner's manual......first thing to try would be a factory reset...sometimes this will un-scramble the operating system and

...in the vicinity of the rotary encoder.  Also look at solder connections to make sure they are sound.  A little contact cleaner applied to encoder through an opening so the spray gets

I have a Korg concert piano model c-303. have had it since 1995. Never a problem until a year or so ago. When you turn the power switch on, sometimes it comes on for a while, but then off again. I'm ...