I'm 100% sure I've wired everything right and I can get MIDI signals from MegaDrum but I don't see anything on LCD. What is wrong?
If this a latest version of MegaDrum without an LCD contrast pot than
you need to adjust the LCD contrast from the MegaDrum menu. After MegaDrum is
powered up, press UP/DOWN to adjust it. If this is an older version of
MegaDrum than there is a 10k VR1 in it. You set LCD contrast with it.
The potentiometer, you have, might be a multiturn type so you might
have to make several revolutions to set correct LCD contrast.