A damaged/disconnected thermistor can easily be spotted by checking the temperature monitor on the top of the user interface on the printer.
- Remove the print head cover.
- Disconnect the power and thermistor cables.
- Use a Phillips screwdriver to loosen the bolt keeping the Hotend in place and pull it out.
- Remove the silicon sock covering the heat block and loosen the thermistor screw using an Allen wrench.
- Pull the old thermistor out of the heat block, push the new one in and align the tip with the heat block.
- Fasten the thermistor screw and slip on the silicon sock again.
- Fasten the Hotend screw again while pushing the Hotend upwards.
- Connect the power and thermistor cables again.
- Put the print head cover back on.