Clavinova strange key sounds

Came across an old CLP-155 that has been dropped on the front keyboard. Aside from a bent front rail and one broken key, there appears to be no other damage. There is a strange noise on all the keys when played. It sounds like it is playing more than one tone with echo.
–The issue is present on all keys and all voices.
–The sounds are the same from the built in speakers, external amp using aux out and both headphone jacks.
–I’ve reset the keyboard and reseated all connections without resolve.
–Since is is present on all keys, I think I can rule out a sensor board issue since there are three boards on this keybed.
–Could this be a sensor strip issue?
–One more piece of info, I connected midi out from the CLP-155 to another keyboard and it sounds great. So, it looks like the keybed is not the issue. Ugh. I was hoping for an easy sensor strip replacement. Thanks in advance…Tony