Mainboard Replacement

Required Components

  • Any 3D printer mainboard with support for:

    • 24V DC power

    • 3 stepper motor drivers (TMC2209 or better for X, Y, and Z)

    • Sensorless homing for X and Y is required

    • At least two endstops (optical Z endstop and filament sensor

    • At least one heater output (bed)

    • Two thermistors (bed and chamber)

    • Has 3 fan outputs (ideally 3 pins, for mainboard cooling, side, and chamber)

  • USB 4 Port 2.0 (or 3.0) hub

  • spare USB cable for connecting the camera

    • Printer cables (USB-B to USB-A) are good sources

  • JST-HX 2.54mm kit that includes an assortment of 2/3/4/5/6 pin connectors.

  • 5x Crimp on ferrules (for bed heater trigger, z endstop, and chamber LED lights)

  • 18 AWG stranded silicone wire (For stock toolboard power, preferably red and black.)

  • 2x Spade connectors (For stock toolboard power leads)

  • 3D printed mount for mainboard.

Steps to replacing stock mainboard with COTS mainboard

  1. Disconnect all connectors from mainboard.

  2. Remove power wires from mainboard screw terminal.

  3. Remove glue from USB-C and disconnect.

  4. Remove screws for mainboard and mainboard itself.

  5. Install 3D printed mainboard mount.

  6. Install replacement mainboard.

  7. Swap JST-XHB connectors to be JST-XH connectors.

  8. Reconnect JST-XH connectors and power to mainboard.

Components: 1x Mainboard Mount, 1x Mainboard

Tools: M3 Allen Wrench, Philips Head Screwdriver

Never remove a board connector by pulling on the wires themselves, doing so risks potentially damaging the wire inside the wire's insulation or damaging the pin connection. If a connector is stuck and will not come lose, place your fingers on either side of the connector and, with a rocking motion, pull upwards until the connector comes loose.

Always verify the orrientation and polarity of a connector on the board before wiring or connecting a component. Components that are polarized can be damaged if connected incorrectly.

Rewiring Board Connectors

Unless otherwise stated all connectors need to be de-pinned and re-pinned to JST-XH 2.54mm pitch connectors.

X, Y, and Z

JST-XH-4P, Connect to X, Y, and Z.

Thermistor Bed (BED-T), Chamber (BOX-T)

JST-XH-2P

  • BED-T

    • BTT Octopus: TH0

    • BTT SKR Mini E3 V3: THB

  • BOX-T:

    • BTT Octopus: TH1

    • BTT SKR Mini E3 V3: TH0

Bed Heater Trigger (HBED)

Cut the pins off flush, strip approximately 0.25in/6mm and crimp ferrule to each wire. Connect +24V DC to +24V DC bed_out/HB, and -24V DC to -24V DC bed_out/HB. Tighten screw terminals until snug, gently tug the leads to ensure they are fully secure in the terminal block.

Z Endstop (EXT)

Insert signal and ground pins into JST-XH-3p connector, do not install power as stock endstop is +24V DC and needs to be terminated with a ferule inserted with mainboard VCC+ 24V input. Connect to Z endstop on mainboard and route +24V to mainboard +24V DC terminal don’t screw down terminal yet.

Filament Sensor

JST-XH-3P, Install to available endstop on mainboard.

Fans

JST-XH-2P, mainboard fan (BFAN), Side fan (FAN-1), and rear intake blower fan (BOX-F). Connect mainboard fan to FAN0, side fan to FAN1, and rear blower FAN2.

Camera

The camera is a standard USB camera wired to use a JST-XHB-4p connector, in order to use the camera it will need to be connect to a standard USB-A cable for connection to the SBC.

LED Lights (LIGHT)

Cut the pins off flush with wire cutters, strip approximately 0.25 inch/6mm, crimp on ferrule to each wire. Connect the wires in accordance to the mapping below for your board. Tighten screw terminals until snug, gently tug the leads to ensure they are fully secure in the terminal block.

  • +24V DC:

    • BTT Octopus: HE0 24V

    • BTT SKR Mini E3 V3: E0 24V

  • -24V DC:

    • BTT Octopus: HE0 PA2

    • BTT SKR Mini E3 V3: E0 PC8

Components: 4x JST-XH-4p Connectors, 2x JST-XHP-3p Connector, 5x JST-XH-2p connectors, 5x ferrules, 1x USB Cable

Tools: JST-XHB De-pinning tool, Wire Stripper/Cutters, crimp tool for ferrules

Toolboard USB-C

In order to use the stock toolboard a USB-C breakout board is needed to separate the RX/TX data lines from the 24V DC power wires.

  1. Cut the end of the USB cable off flush with a pair of wire cutters.

  2. Strip off approximately 1in/25.4mm of the outer jacket.

  3. Strip approximately 0.25in/6mm of insulation for each of the wire's insulation.

  4. Cut the USB +5 VCC wire flush with the USB cable outer jacket.

  5. Solder the USB D+ wire to D+.

  6. Solder the USB D- wire to D-.

  7. Solder a length of 18AWG wire (red), capable of reaching PSU from mainboard mount, to VBUS.

  8. Solder a length of 18AWG wire (black), capable of reaching PSU from mainboard mount, to GND.

  9. Crimp spade connectors to both wire leads.

  10. Complete toolboard flashing before connecting power leads.

  11. Connect VBUS +24V DC and GND -24V DC leads to PSU.

Never connect the stock toolboard to a computer when powered by 24V DC! Doing so will damage the USB port of the device connected.

Components: 1x USB Cable, 1x USB-C breakout board

Tools: Wire Stripper/Cutter, soldering iron and flux core solder, flush cutters