I've been reading Pablo's responses to a problem common to some users where a group of 8 consecutive keys goes dead to pianos and samples although organs may still respond. The suggested fix was to detach and reconnect the ribbon cables between the keybed and main board.
The uppermost Ab to Eb on my NE4SW developed just this problem recently. I had 2 gigs coming up, and since the effected keys were high up and seldom used I waited until after the gigs before attempting a repair.
I followed Pablo's dismantling procedure during which I disconnected the 3 ribbon cables between keybed and mainboard, then also from under the keybed, then reseated all ribbon connectors during reassembly.
Sadly the symptom remained. In fact I made it worse. On my first power-up and test I just went as far as plonking a few keys in the upper registers to confirm that the same Ab - Eb were still not working, but that others above middle C were working. A day later I realize that
- much of the keyboard below middle C has gone silent
And that some are not sounding on organ either.
- the keys that ARE working (Bb down to E in the octave immediately below middle C) are sounding at full velocity, usually a dirt-on-the-contacts problem, but it doesn't seem possible in this case.
- PLUS those same keys are sending a MIDI note that is a semitone higher than the physical key that is pressed!
I've fixed 'full velocity' keys in the past but might have exceeded my skill quota on this occasion!
Thanks very much for your time
Regards
Jon May (Queensland Australia)