Program Changes

I’ve recently bought an Ambika, and am stuck with making program changes, despite reading both manuals, the MIDI implementation sheet and searching this forum. I’d appreciate your help with what should be a simple enough problem.

I’m controlling the Ambika from my Korg Kronos, and am well used to controlling other synths with it.

I have the Ambika set up with all of the filters disabled, so nothing is being blocked. However, no matter what combinations of CC000, CC032, internal program change messages or the MIDI ext settings on the Kronos I try, I can’t make a bank change happen - the result is always stuck in Bank A. Any idea what I’m doing wrong?