1 SVF voicecard not behaving as expected

So I just received a 2nd hand Ambika from a guy on the forums here and I’m after a bit of troubleshooting advice.
The Ambika has 4xSMR4 and 2xSVF voicecards.
One of the SVF voicecards (voice 6) doesn’t give the right filter types as specified on the screen.
With ‘lp mode’ selected I actually get a bandpass filter, in bp mode I get a bandpass filter and in ‘hp mode’ I get a lowpass filter…
Could this be a firmware issue or a hardware issue?
Any help is much appreciated :slight_smile:

This is crazy!

Compare the voltage on IC4 pin 9 and IC4 pin 10 on both voicecards.

Is there any difference?