Next Day Reprap

Prusa Mendel Build Manual

Prusa Mendel Build Manual

Step by Step Detailed Instructions for building your Prusa Mendel

reprap prusa mendel kit

9.0 Wiring – Reprap Prusa Mendel Build Manual

9.0 Wiring – Reprap Prusa Mendel Build Manual

9.1 Parts Required

Parts Required
  • Assembled RAMPS 1.4 Board
  • Stepper Motor Crimps and Connectors

RAMPS 14 Wiring Diagram



9.2 Completing Connections

Everything has been pre connected and soldered other than the stepper motors which need to be crimped. (no soldering)

Your Nema Stepper Motors will require the plastic molex connectors crimped and connected to the wires before you can attach them to your RAMPS hardware. The following instructions will guide you through the process. If you are experienced at this type of connection we recommend that you put small amount of solder on the crimps to ensure there longevity. You should always double check the order the the wires are connected before pushing in to the black plastic molex plugs as they are very difficult to change.

Step 1

Take the four colored (Red, Blue, Green, Black) wires from the Nema Stepper Motor and strip 5mm of the plastic sheath from each of the wires.

Reprap Prusa Mendel Completing Connections Step 1


Step 2

Take one of the Crimp connectors and place the Red stripped wire as shown below. Ensure the longer metal prongs on the connector line up with the sheathed part of the wire. The bare wire should sit in the centre of the connector.

Reprap Prusa Mendel Completing Connections Step 2


Step 3

Now crimp down the smaller metal prongs. Ensure they hold the wire tight. Make sure there are no loose or frayed strands of wire.

Reprap Prusa Mendel Completing Connections Step 3


Step 4

Crimp the larger of the prongs around the sheathed part of the wire. Ensure these grip the sheathed wires, but do not crush the wire. Ensure your crimps are small and tight on the wire. Ensure the connector is not bent. The whole of the metal connector will slide in to the plastic Molex connector so you should ensure there are no wires hanging and the metal crimp is secure.

Reprap Prusa Mendel Completing Connections Step 4


Step 5

Repeat the the process until all four wires from the stepper motor have connectors attached.

Reprap Prusa Mendel Completing Connections Step 5


Step 6

Take a plastic Molex connector and hold it so that the cut outs on the flat side face you. Line up the Red wire with your crimp connector. The crimp should have the flat side down. The red wire goes in to the right hand hole in the connector.

Reprap Prusa Mendel Completing Connections Step 6


Step 7

Slide the connector in to the Molex connector as shown in the photo. The connector must slide all the way in until your feel a click as the crimp connector locates in to the plastic. If your crimp will not go all the way in, check that your crimped prongs are tight enough. To check that your wire is all the way in look in to the molex connector and the crimp should be visible and you should see that it is in as far as possible.

Reprap Prusa Mendel Completing Connections Step 7


Step 8

Repeat fitting the connectors in the molex connector for each wire. Ensure the order matches the photo below. From left to right it should be Black, Green, Blue and Red.

Reprap Prusa Mendel Completing Connections Step 8


Step 9

Repeat the steps for all five of your stepper motors. You are now ready to connect to your RAMPS Board.

9.3 RAMPS 14 Board Diagram



9.4 Making Connections

You can now connect your printer to the RAMPS Hardware. Your RAMPS board already has two cables connected, these are for the Hotend thermistor and power, the ends are labeled. You should place your ramps board the to rear left hand side of your printer. Run the Hotend cables over the printer and drop through the upper threaded rods Connect these to your Hotend. As you connect your components to the ramps board use cable ties to hold the cables against the frame and ensure no cables are trapped or touching moving parts.

We recommend loosely tidying cables until your printer is fully running and then making permanent later. Make sure when connecting plastic connectors, that the pins are fully inserted in to the plastic plugs, but have not pushed the connector out of the plug housing.

Step 1

Start by connecting the Heated Bed power cable to the screw terminals labelled D8 on the Ramps Board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 1


Step 2

Connect the Heated Bed Thermistor to connector labelled T1.

Reprap Prusa Mendel Electronics Wiring & Connections Step 2


Step 3

Connect the X Endstop Microswitch to the connector labelled x. Ensure the black cable is closest to the centre of the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 3


Step 4

Connect the Y Endstop Microswitch to the connector labelled y. Ensure the black cable is closest to the centre of the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 4


Step 5

Connect the Z Endstop Microswitch to the connector labelled z. Ensure the black cable is closest to the centre of the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 5


Step 6

Connect the X Motor to the connector labelled X. Ensure the Red cable is closest to the green screw terminals on the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 6


Step 7

Connect the Y Motor to the connector labelled Z. Ensure the Red cable is closest to the green screw terminals on the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 7


Step 8

Connect the first Z Motor to the lower connector labelled Z. Ensure the Red cable is closest to the green screw terminals on the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 8


Step 9

Connect the second Z Motor to the upper connector labelled Z. Ensure the Red cable is closest to the green screw terminals on the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 9


Step 10

Connect the Extruder Motor to the connector labelled E0. Ensure the Red cable is closest to the green screw terminals on the RAMPS board.

Reprap Prusa Mendel Electronics Wiring & Connections Step 10


Step 11

Connect Power Supply cable to the green socket.

Reprap Prusa Mendel Electronics Wiring & Connections Step 11


Step 11

Connect Power Supply cable to the green socket.

Reprap Prusa Mendel Electronics Wiring & Connections Step 11


Step 12

Connect the other end on the Power Supply cables to the cables on your main power supply. The smaller connector has only one matching connector on the main power supply. The wider connector will atatch to any of the matching connectors on the main power supply.

Reprap Prusa Mendel Electronics Wiring & Connections Step 12


Step 13

Connect Power Supply cable to the green socket.

Reprap Prusa Mendel Electronics Wiring & Connections Step 13


Step 14

We have supplied a generic electronics enclosure (RAMPS Box). This isn’t specifically designed the Ramps board, so feel free to cut and modify the box in order to locate the electronics how you wish, a small hacksaw, or sharp knife should be suitable for cutting the box. We have done this as there are many ways of locating the electronics on or around the printer and we felt this should be up to you.

Please note however don’t put the cover on the box unless you are providing additional cooling ( fans etc) otherwise the RAMPS board won’t receive enough ventilation. All of our machines run without fan cooling, but the tops of the RAMPS Boards are left exposed, hence we don’t supply a fan.

Also we wouldn’t recommend making any of the wiring runs/routing permanent, until you have completed section 11.0 Commissioning and have completed your test prints and are sure everything is 100% connected correctly and working.

Reprap Prusa Mendel Electronics Wiring & Connections Step 14 Reprap Prusa Mendel Electronics Wiring & Connections Step 14

If you want to cover the box, you will need to implement additional cooling as the convection cooling effect without the lid on will no longer occur with the lid on. Some Examples You could connect a PC Case fan to one of the spare 5v molex connectors on the Power supply for a permanently running fan. You could mount pc headers onto one of the RAMPS Boards AUX Mounts and then control the fan using the host software.



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We can now proceed to 10.0 Reprap Prusa Mendel Computer Setup



Prusa Mendel Parts Help and Support