My Roland PK-5 started acting funny last week. Any pedal I pressed would get stuck and I’d have to step on it multiple times to get it unstuck. Completely unusable at band practice. Sometimes I had to switch off the synth because it wouldn’t stop playing the stuck note. There’s no PANIC mode on the PK-5 and not one on Logic Pro for iPad as far as I know, otherwise I would have used that.
So I took it apart. Under the black rectangular pieces in the photo above, there are rubber membrane pieces with carbon on the underside, much like the photo on the left (not mine). Those little carbon bits are pressed down on carbon lines on the PK-5’s circuit board and that is what closes the circuit and creates the electrical signal which is turned into a MIDI note, that drives your synth, etc., etc..
If you like De-Oxit like I do, hold off using it to clean the carbon contacts. Here’s something I found on Reddit:
Clean the pcb contacts with alcohol. You can add graphite (from a pencil) to the carbon feet on the bottom of the rubber strips. Try rubbing a pencil on paper A LOT (to the point of having a small pile of graphite on the paper), then rub the black carbon feet from the contact strips on that. Make them nice and shiny with graphite. Should work like new afterwards.
https://www.reddit.com/r/synthesizers/comments/vl7gt2/key_stopped_working_contacts_look_clean_whats_the/
-TG, 11-22-24