> Everything else is working OK but I was using the Mix Out (LFO out) to
> drive my Plan B model 13 when it suddenly stopped outputing its CV signal!
>
> Any thoughts on what could have gone wrong or how to fix it would be
> greatly appreciated!
>
> Cheers,
> theglyph

My first idea: the internal connection is broken. It's a blank wire that
connects the solder point "JP4" of all four boards, located behind the mix
polarizer potentiometer at the pcb edge. But I'd wonder why this should
break if the module is connected to Peter Grenader's model 13 :-)

If this is not the reason: check the common output socket.

Otherwise the module has to be repaired.

Best wishes
Dieter Doepfer