From my understanding, the ribbon, is a plastic part that lies under the keys and sends messages how hard or soft or fast the keys are played. Usually in the middle C area it gets burnt out. Meaning the key action sound response isn’t as quick and accurate as it should. Is it best to replace all the key ribbon than just the one or two funky keys. My authorized dealer who is more of a electronic repair guy just hires a piano tech and didn’t do a good job. He just replaced a broken key. Is there anyway to get a Kawai repair guy to come over the house and repair the ribbon? NY area…
Have the keyswitch circuit boards with contacts replaced. It’s a set. The part number is
C11-KSA-ES7 KKB-044. But call KAWAI America to make sure it’s correct for your ES7 and cost.