We hope this info is helpful to anyone who is new to this great Forum.

We are aware that his info has already been shared at an earlier time by someone else in the Forum.

To resolve the dead key/note issue 🎹 on our Ketron SD5 we tried the usual suspects of cleaning the contacts and reseating the ribbon connections but this surprisingly did not repair the dead note issue.🎹

As a last resort, we swapped out the rubber key contact bumpers from a section of the keyboard that we do not use as frequently and this proved that the problem was a bad contact in the rubber key contact bumper.

👍Kudos to AJ of Ketron USA for promptly responding to my inquiry on a Sunday to set up the purchase & shipping of a replacement set of rubber bumper key contacts.

AJ promptly shipped the part to us the very next business day.✨

We hope this troubleshooting 💡technique/repair might help a fellow Synth Zone member.