There are several reasons that may cause such an issue. Please follow the below to do the troubleshooting.
- Please check whether you are using the correct screws to install the printing module to the X-axis. The correct screws should be M4x8. If you are using a longer screw, it will cause the short-circuit issue and it will show Laser or CNC module on the touch screen.
- If the screws are correct, please unplug the power supply from a power socket, take off the printing module, and then open its left-side board. After that, please unplug the thermistor (the white cable) as the below picture.
This time, please go to check again whether the touchscreen shows the printing module when starting the machine.
If it shows the printing module, the issue is related to the thermistor. You may need a new thermistor to replace the old one. Please refer to the link to replace the thermistor. https://youtu.be/iuZ5nKHFW-w
When there is a short-circuit in the thermistor, the touchscreen will also show the laser or CNC module. In this case, you need a new thermistor as well.
Please send an email to firstname.lastname@example.org if you need further help.