Phenomenon: The nozzle temp shows more than 300° on the touchscreen or in Luban
1. The below cable circled in red is the thermistor. Make sure it is inserted into the small hole correctly and properly.
2. Open the left cover of the printing head and check whether the pins below are bent or defective. Please refer to the below picture.
3. After unplugging the cable of the below one, please use the Ω mode of the multimeter to test the two pins. The test result should be more than 50KΩ.
(The two tested pins are highlighted.)
Noted: Connect the below cable with the hot end cable when testing the pins.
4. Power on the machine, and use the voltage mode of the multimeter to test the below circled in red. The test result should be around 3.3V.
Please send the test results to firstname.lastname@example.org and we will help you further. Thanks