CENTERVILLE,
if it was mine, i would try to
(blow out the area around the circuit boards with compressed air)
pecific
(CAREFULLY, unseat ever connector & ribbon cable, spray with a good zero residue contact cleaner, reseat the cables)
(do all the obvious things, clean encoding strip with recommended cleaner, a drop of lubricant everywhere the manual says it is expected)
i have no specific experience with your model, but have fixed more rolands than i can count. is there anything in particular you do thatbseems to trigger this error?