Replicator Extrusion Motors Reversal Instructions:
Final Result after swapping the motors front to back.
Goal: To flip the extrusion motors around so the fans were in the back and the motor shafts were
visible in the front of the extruder. Note In this picture, I have extruded and glued a disk to the end of
the motor so watch the rotation and judge if the filament is slipping against the pinch roller. I have also
extruded and placed a guard over the fans (as seen in the picture above).
Reason: I don’t really care to see the cooling fans but I do want to see the extruder motor shafts to
help gauge extrusion speed and help diagnose filament feeding problems. I also broke a few blades on
one of the cooling fan as a result of sticking my fingers into the exposed fan.
Overview: The job of switching the motors around is fairly easy and well worth it. Don’t attempt if
you are not handy with tools.
Note that this modification, while it doesn’t permanently alter the Replicator in
any way, probably voids the manufacturer’s warranty and for that reason, I don’t
recommend you do it. I did this at my own risk and assumed all responsibility had
I experienced any problems.
Since making this modification, I have experienced no negative consequences as a result.
Procedure: I have tried to make this a step-by-step but it has been a while since I did this so forgive
me if I have left anything out. Please read through the entire procedure a time or two before starting. If
you have any issues or need clarification, please leave me a comment and I will try to help you out.
WARNING: The next steps will expose the circuit board which can be damaged
quite easily by static electricity. During the next few steps, DO NOT walk across
the wool carpet and then reach in and touch the circuit board or any wires
attached to the circuit board. When you are ready to begin, ground yourself to
the exposed metal cover that is over the SD memory card. This will drain off any
static charge you might have picked up.
1. Remove power to the replicator and unplug the USB cable. Do this after grounding yourself to
the metal cover over the SD memory card.
2. Remove the single 3mm socket head cap screw located midway between the front and back of
the Replicator and just above the cutout along the bottom. This will allow the plywood cover
that protects the electronics to be removed.
3. Mark the white connectors that plug into “AStepper” and “B-Stepper”. Then unplug them and
plug the connector marked “A-Stepper” and plug
it into the “B-Stepper” slot and the connector
marked “B-Stepper” and plug it into the “AStepper” slot. This will swap the left & right
extruder motors.
4. Mark the wires connected to “EX1” + Fan, -Fan and “Heat”. Do the same for “EX2”. Loosen the
terminal screws on the circuit board and move the wires from the “EX1” connector and reconnect them to the “EX2” terminals. Note that the +Fan wire is RED, the –Fan wire is black for
both fans. The heating element wires (both white) are not polarity sensitive. This will swap the
left and right fans and heaters.
5. Mark the
thermocouple wires
connected to “R1”,
“Y1”, “R2” and “Y2”.
Move the wires
marked “R1” & “Y1”
to the terminals
marked “R2” & “Y2”.
Connect the wires
marked “R2” & “Y2”
to terminals “R1” &
“Y1”. This will swap
the left & right
thermocouples. Be careful with these wires as they are thin and delicate. Note that terminals
“R1”,”R2” connect to the Red wires, “Y1”,” Y2” connect to the yellow wires.
6. Inspect your work on wiring and then put the plywood cover back over the circuit board and reinstall the 3mm socket head screw.
7. Remove the two 3mm SHCS that hold the aluminum bar to the plastic carriage. Gently lift the
motor assembly away from the plastic carriage.
8. Loosen the two set screws that hold the heating elements into the aluminum heating blocks.
Once the heating elements are loose, slide the elements out and stick them in the holes from
the opposite direction. Gently tighten the set screws again. By reversing the direction of the
heating elements, you will provide some clearance so the heating elements don’t touch the
plastic carriage.
9. Spin the motor/heater assembly 180-degrees and place back on the plastic carriage. Below is
what my carriage looks like from below. Re-install the two 3mm socket head cap screws to
secure the assembly to the plastic carriage.
10. It might be necessary to rotate the aluminum heating element blocks so the thermocouple
screws doesn’t touch the plastic carriage (see picture above). This is done by loosening the
extrusion nozzle which allows the block to rotate. Once the block is rotated properly, tighten the
nozzles to lock them in place.
11. The last thing to do is to swap the home limit switches for the X & Y axis since the X-Axis switch
doesn’t have the metal arm and the Y-Axis switch does. Remove the X-Axis limit switch from the
right end of the carriage assembly. Disconnect the cord from the connector and set the switch
assembly aside. I believe there was a screw that holds the small circuit board in place. Remove
the Y-Axis limit switch from the left end of the extruder. Again, unplug the cord from the
connector. Place the Y-Axis switch assembly below the two plastic fingers on the right hand end
where the X-axis switch assembly was (see picture below of the revised X-axis switch assembly).
Note that you will need to bend the steel switch lever out slightly to contact the edge of the
aluminum heat sink when the carriage is in the X-Home position.
Bolt the Y-axis switch assembly in place using the two screws. Note that the Y-Axis switch
assembly doesn’t have the steel finger now but this is ok as the plastic carriage pushes the
switch plunger in properly.
12. This completes the procedure. I do remember having to switch the direction of one or the other
extruder motor. If that if you find that it is going in the wrong direction, leave me a comment
and I will tell you how to do that.