Sequential circuits samplers

I had a similar problem on my p2k keyboard sometime before the kybd 
controller chip finally expired, forcing me to retire the instrument. I still use my 
2k2 though.

the keyboard uses rubber pads that each land on a trio of contacts on a pcb. 
as I recall, velocity is sensed by measuring the delay between the outer ring 
of the pad shorting it's contacts and the centre of the pad landing on a 
central contact. so beyond dismantling and carefully cleaning this arrangement, I 
can't offer any other diagnosis.... I think it would be an odd fault for the 
keyboard controller to lose velocity sensitivity for a specific area like this.

unless... (light bulb comes on over head) the non-responding range is like 
that because that area of your keyboard mapping has no velocity-affected 
parameters set up.... try firing the thing up with no disc (i.e. using the internal 
wave sounds and presets) and see if the same thing happens.

duncan/r.m.i.