Several weeks ago, a user wrote about a problem with "all of her F#'s being out".  Apparently the optical sensors on the ends of the keyboard's keys are grouped together.  If one goes out for one key, the same key in the other octaves are affected.  The optical sensors are located on a back-plane that runs the length of the keyboard at the end of the keyset.

Also, it could just be a controller card.

Brandon Amison
Yaking Cat Music Studios
and Synclavier Information