Cupcake Electronics Installation

This page is part of the CupCake CNC build sequence.

STOP! Check that the 110V/220V switch on your power supply is set correctly.

Connect the power supply


Connect the four-pin molex connectors from your ATX power supply to each of the stepper boards. Connect the 20-pin connector to the motherboard. All the sockets are keyed, so it should be clear which way around each connector goes.

Your power supply may have what appears to be a 24-pin connector. Don't panic! It's actually a 20 pin connector with an extra 4-pin connector attached on one end. You can slide the additional 4-pin connector off, as shown below.

After that, find the molex connectors among the power supply wiring. The molex connector is a chunky 4-pin connector with a trapezoidal tip. It's the kind of power connector that plugs into an internal cd-rom drive in a computer, if that helps. Hook one 4-pin molex power connector up to each of the 3 stepper motor drivers. If you have a relay board, that also gets a molex. Be mindful that it is inadvisable to chain y-splitters — if you have multiple y-splitters, then connect each one to a separate molex plug off of the power supply. We advise that the Relay Board kit be served directly by the power supply when possible.

Assemble your ribbon cables

If you haven't done so already, assemble the ribbon cables that came with your stepper drivers. the directions on the RepRap wiki for details. Make sure that both ends of the cable are hooked up in the same way— the engraved arrow on the IDC connector should line up with the same colors on both ends.

Wire up the stepper boards


NOTICE: DO NOT hook the Stepper Motor Drivers up to the Motherboard with the Cat5(ethernet)patch cables. This causes your Stepper Drivers to become damaged. Bad news!
Use the ribbon cables with the IDC sockets to connect the stepper driver boards to the labeled X, Y, and Z connections on the motherboard.

Hook up the steppers


Attach the stepper connectors on the motherboard to the corresponding driver boards for each of the X, Y, and Z axis. One side of each connector should have a couple of small triangular ramps on it; these should meet the corresponding protrusions on the board when the connector is the right way around.

Connect the extruder

If you haven't assembled your plastruder yet, go here.


Plug one end of a patch cable into any of the RJ45 jacks on the motherboard, run it through the holes in the corner of the machine as shown, and plug the far end into the extruder.

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