I have a very old Gen 1 of the Mini, the miniRambo Board was a 1.1b board, and I wanted to add the LCD kit so got a 1.3a board.
I carefully swapped the wiring also compairing it to the Lulzbot wiring diagram. Got the LCD installed, flashed the firmware, and everything was looking good.
The wierd thing was that my printer seemed to have an extra undocumented wire pair. It was black and blue with a 2 wire connector on the end and was attached on my 1.1b on the first set of 3 jumper pins just above the ZMax connection point. I can find no documentation what so ever for what that pin set does or why there was something attached to it.
However after I accidentally crashed by print head into the bed while messing arround with the LCD controller, my printer froze and failed all other communication attempts until I removed the wire. Then everything started working again, and printing is working just fine, and I am super happy have that LCD control. Just being able to easily adjust the z-offset is heaven and being able to easily remove filament etc without going through Cura is awesome.
So does anyone know that that mystery wire is for? was it a failsafe for crashing the head into bed? But then why would the printer become un-usable after that happened? I haven’t tried re-connecting the wire since. And prints are fine, but I worry that I am missing something by just leaving that wire hanging. All other wires in the wiring diagram are attached so this is clearly an undocumented extra wire. No idea what it is actually attached to in the printer.
Picture of the pins it was wired to is attached, I drew a blue box around the pin in question just above the ZMax