The Elf wrote: ↑Fri Aug 19, 2022 5:57 pm
I assume the power comes from the XK5's 11-pin socket to the Neo? At least that's what the diagram and photo in my first page post seem to imply?
That square blob on the left of your diagram labelled 'pwr' is a socket which expects to receive a +12V DC supply, and route it to the XK5 on pin 11 to tell it that a (fake) Leslie is connected. Without that external voltage the internal Leslie processing won't be bypassed and the onboard Leslie switches won't control the external unit.
So... you need to squirt 12V into the 11 pin plug, but it only needs the voltage; it doesn't draw any significant current...
And you also need to pump 12V into the Neo pedal...
So one reasonably practical option would be to wire a 12V supply into the 11 pin socket, with a loop-through to power the Neo. That's the suggested arrangement in the DIY article on Neo's website anyway. Alternatively, you could use a separate 12V wall wart wired into the 11-pin just for the organ.
Interestingly (if you're that way inclined), the XK1c and SK1/2 use an 8-pin Din for the Leslie connection, and that just needs to see a ground on one pin to think there's an attached (fake) Leslie, which is much more sensible.