[sdiy] CS70M aftertouch

[John Henson]

Hi Greg,
I worked on a CS60 a few years ago that had a similar aftertouch system,
a metal vane opened up to allow light from a bulb to shine on a 
photocell which generated the pressure voltage. From the sound of it, 
your problem is with the mechanics of the system, perhaps a strip down 
clean and lube of the mechanism may cure the issues, or else the wrong 
type of spring is in it.