Hi Bram
yes all power connectors are centre pin +ve...although you can bet sometimes someone will get it wrong or decide to swap them around in design!
I received the encoders today and will do some work on the system...it's a bit hot atm so I'll be trying to keep away from the soldering iron! Nearly all over..."bar the shouting!"
Interesting to see that Martins worked at my place fine but he experienced teething ASCOM issues on his set-up. I may be creating more headaches for Dave than he'd like!
Brendan