The 'E' above middle-C in this Korg Kronos music workstation made a sharp clacking sound when played hard.

We discovered that the clacking sound was caused by a damaged piece of felt that the key hammer hits when thrust upward by a key push.

We removed the Kronos keyboard assembly, then cut out and replaced the damaged piece of felt (left).

Because of the damaged felt, the key hammer traveled too far upward, striking the metal key frame instead.

There was a dark line on the frame where the hammer was hitting (left).