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the expression pedals, IIRC from
taking the back off of my fcb1010 a while ago, are optical. the mechanism uses a
graduated curve of transparent plastic attached to the pedal, which moves back
& forth through a photo-transistor/LED pair.
something might be occluding the
PT, or maybe some contaminant has built up on the transparent plastic part, or
else the PT is "going off"- becoming unstable through noise or just beyond the
limits of the unit's ability to calibrate it. taking the back off the board
& inspecting the assemblies in question would provide an opportunity to
clean them of any ingress, but then a visit to a behringer dealership would have to be next on
the list, I'd say.
I have a number of fairly
sophisticated walkmans that use PT/LED sensors in their logic circuitry, that
have failed in this manner.
just a thought.
d.
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