GOSH!!! Just bought this Thing. Used but in good shape (from what I can tell). Well my son turned it on just now and all of the D and C keys have major problems. The lowest 2 octaves of each play no matter which octave you play and all D and C keys have max volume triggered no matter how light you hit the keys. What a damn nightmare. Thing is totally useless as it sits. Anyone know how to deal with this. I tried a factory rest to no avail. Thanks - Paul