Thermocouple error fix

The thermocouple is the part tightened in the bandheater. The thermocouple ensures that the temperature of the bandheaters is measured. It may happen that the thermocouple malfunctions or does not function at all.

Before the thermocouple needs to be replaced, it can first be tested if it is correctly connected or that the cable does not cause an error message. This manual describes step by step the action points that need to be taken to check whether the thermocouple is still working. If the thermocouple still does not work then it needs to be replaced.

Before you start

Collect the following items:

  • Soft cloth or towel
  • Hex key 2.5 mm for M4 bolts
  • Tie wrap
  • Rubber gloves
  • Wrench 10
  • Piece of foam or wood or something similar to bring the machine up to height

Locate problem

Step 1: Determine which thermocouple is causing the problem. You can see this on the OLED screen, the heater causing the problem is the heater with a lot of numbers, or displaying the ‘0’ (zero) where the degrees should be.

Step 2: Turn the machine off.

Remove top hood

Step 3: Follow the instructions to remove top hood and after finishing continue to step 4.

Raise the machine

Step 4: The machine must be brought up to height to remove the winder cover. Use a piece of foam or a piece of wood or something similar to bring the machine to the right height.

Remove winder plate

Step 5: Remove the winder side plate. First unscrew the adjusting knob by hand.

Step 6: Now unscrew the 6 bolts with the Allen key. First unscrew the 5 bolts, shown with the red arrows. Loosen the bolt with the blue arrow indicated last. Beware! The winder plate can now fall off the machine. If the winder plate is loose, carefully place it somewhere where it cannot be damaged.

Step 7: Check if the thermocouples are correctly connected in the Devoboard, which is placed on the side of the machine. The first left plug is for thermocouple 1, next to it is the plug for thermocouple 2, 3 and 4.

Step 8: Now plug the power plug back into the filament extruder and turn on the extruder. See if there is no more error message in the display. Should the thermocouple work again then go to step 20. If the thermocouple still indicates a strange value or still don’t work then unplug the faulty thermocouple free from the Devoboard and go to step 9.

Step 9: Wear rubber gloves to protect your skin against irritation caused by the isolation wool.

Remove isolation wool

Step 10: Depending which thermocouple must be replaced, cut and remove the tie-wrap. Thermocouple number 1 is located at the front of the machine at the nozzle. Thermocouple number 4 is located at the end of the barrel, closest to the hopper.

Step 11: Open up isolation wool and spread until the failed thermocouple is exposed.

Unscrew the thermocouple

Step 12: Carefully unscrew the thermocouple with a spanner from the heater, but make sure to do it gently.

Step 13: Cut with a cutter the tie-wrap which belong to the faulty thermocouple.

Step 14: Carefully remove the thermocouple from the machine. Then carefully pull out the cable 1 to 2 mm out of the thermocouple. Do this very carefully! Don’t pull the cable out of the thermocouple.

Step 15: As soon as the cable is carefully pulled out of the thermocouple by 1 to 2 mm, it can be carefully re-installed in the heater.

Tighten the thermocouples hand tight and then another eighth turn (1/8) to a quarter turn (1/4) carefully with a spanner. Note, the thermocouples do not have to be turned very tight, otherwise they will be damaged in the heater.

Step 16: Plug the cable into the Devoboard.


Step 17: Turn on machine and check on OLED screen if the error is still there.

No error? Place the hood back on and the machine is fixed.

Error still occurs? Send an email to

Cable management

Step 18: Lay the cable of the new thermocouple again gently through the frame and connect it with a tie-wrap.

Step 19: Close the isolation wool again with tie-wrap.

Step 20: Close the machine.

Place top hood

Step 21: Follow the instructions to remove top hood in the inverted order.