I just did a google search for "megadrum pinout" & that was one of the 1st links I clicked on.
https://www.megadrum.info/sites/default/files/MegaDrum%20kit%20-%20instruction%20manual.pdfI also found a scribd link to the same manual with the 1,2,3,4,5 schematic.
https://www.scribd.com/document/135894761/MegaDrum-Kit-Instruction-ManualAnd then this one from what I assume is a mirror site/address.
https://www.megadrum.uk/sites/default/files/MegaDrum%20kit%20-%20instruction%20manual.pdfI can't see any way to find them through the site and forums themselves. Only by searching.
Thank you for your help Dimitri. Much appreciated.
Will see how I get on with the board tomorrow armed with a fresh mind.