I've got a CDP-130.
While I was playing, a range of 8 keys suddenly lost touch sensitivity. After a short while the next 8 lower keys lost it as well, but regained it after some more time.
I've taken it apart and cleaned it - even removing each key to get at the contact sensors. The rubber contact strips are in good condition and clean.
I noticed each key has two contact sensors - the rubber "buttons" each have two conductive pads: one is longer than the other and would contact first. I assume that velocity sensitivity is achieved by measuring the time interval between the two contacts. I tested "normal" keys by closing only one contact at a time - no sound. Only when both contacts are closed is there sound. When I do this on the "defective" keys I get a full velocity sound just from closing either one of the contacts.
The circuit board the contacts are on looks pretty simple - no ICs or anything, just what appears to be a single transistor for each key. There is no visible damage and the solder joints look healthy on all the transistors. The ribbon cables look good too.
Any suggestions?
