6. Flip the MakerBot Replicator 2 so that it rests on its left side and the bottom of
the machine faces you.
7. Remove the electronics bay cover.
Use the 2.5 mm hex wrench to remove the four bolts attaching the cover to the
underside of the bot. Set the bolts aside.
8. Detach the thermocouple from the Mightyboard.
The thermocouple attaches to a set of terminals at the bottom right corner of the
Mightyboard. If these terminals are secured by buttons, push the buttons on the
terminals to release the red and yellow leads. If the terminals are secured by screws,
use a small flathead screwdriver to loosen the screws until you can remove the leads.
9. Attach the new thermocouple.
Slide the red and yellow leads on the new thermocouple into the same set of terminals.
Remember to attach them to the "A" side rather than the "B" side. The terminals are
labeled "Red" and "Yellow" and it's very important that each lead goes into the correct
one. For terminals with buttons, press the buttons on the terminals, slide the leads all
the way in, and release the buttons. For terminals with screws, slide the leads in and
tighten the screws. Tug on the leads to make sure they're secure. You may find that it's
easier to reconnect one lead at a time.
10. Exchange the old thermocouple for the new one in the extruder cable.
The extruder cable is a bundle of wires taped together at intervals. At each place where
the bundle is taped, carefully cut the tape, remove the old thermocouple from the
bundle, add the new thermocouple to the bundle, and re-tape the bundle.
11. Cut the broken thermocouple from the extruder.
The thermocouple is attached to the back of the thermal core, the block that holds the
nozzle, with a small nut. Snip the wire just above the nut and insulation material.
12. Unscrew the nut.
It's important that the thermal core stay in place. Use an adjustable wrench or pliers to
prevent it from rotating as you unscrew the nut.
13. Attach the new thermocouple.
Screw the nut at the end of the new thermocouple into the thermal core. Again, be
careful not to allow the thermal core to rotate. The new thermocouple should now be
attached to the Mightyboard, the extruder cable, and the extruder.
14. Add the wire wrapping back to the extruder cable.
