Disklavier

Dear DUG,
I have recently added a LINE6 midi device to my Disklavier to connect it to my iPad. It seems to work brilliantly and I am using Synthesia for iPad as a midi playback and learning tool (also great)!

However I have discovered that two keys on the Disklavier keyboard are not outputting a midi signal (E3 and B2 keys) the LINE6 controller shows no signal throughput when either of these keys are pressed.

Is anyone aware if this is likely to be a sensor cleaning or failure issue or any way of resetting these keys?

BTW, if using the standard RECORD function on the piano, the key presses are recognised and recorded, but on playback they play at a reduced level of response, moving as though gently pressed and not striking the strings. Could the record sensors need recalibration, if so, how do I do this?  Both faulty keys are working fine on playback or when 'fired' by an inbound midi signal!

Looking forward to your comments and many thanks in advance.
Ian Woof