Where can I find the system level electrical schematic diagrams for Lulzbot printers, specifically the mini?
The LulzBot Mini shipped with a USB thumb drive that contains the source files used to manufacture that product. You can also download them here: http://download.lulzbot.com/Mini/
These are probably the folders you’d like to look in first:
Motherboard Connections, etc
Bill of Materials for wires, connectors, pins, and whatnot
Parent Open Hardware Assembly Instructions for the LulzBot Mini v1.04 Visit OHAI.LulzBot.com for previous, or other models.
Cables and Harnesses
If you need something specific or get stuck on something post in the forums and you’ll get an answer.
Here’s the Mini rambo 1.2 board diagram. I haven’t found a 1.3 version yet, but it should be nearly the same but with an LCD header http://reprap.org/wiki/MiniRambo