Ensoniq vfx sd channel aftertouch problem

Hello, I have a vfx-sd and the channel aftertouch is very uneven across the keyboard. I’ve looked at the service manual and it kind of says that the inductive calibration was done at the factory for each keyboard. I think mine has lost its calibration data. Does anyone know how to re calibrate one of these keyboards?

I remember that the black keys on mine always used to kick in sooner than the white keys, which I assumed was more of a physical issue than an electronic one.

I believe there are four calibration ‘zones’ for the keybed, controlled by four trim pots on the coil boards, and we have been trying to learn more about this for a while now. If the calibration is way off, the keyboard won’t calibrate with the main board on boot up. On the TS-10 and ASR-10, this can make it seem like the main board is not working, when it is really a keybed issue.

Thanks for the reply Sam. It does seem to be zone related. The upper half of the keybed it fairly responsive, the lower half is much less. I guess I will have to take the thing apart and have a look…