Turn the printer on.

The printer must instantly emit noisy bip just after having started.

The Err: MAXTEMP error message should be displayed on the printer.

The displayed hotend temperature should show a very high value. (See example picture: 739/0°)

Unplug the Dupon test cable and plug back the hotend thermistor. Make sure that the displayed hotend temperature is back to a normal value.

Turn off the printer.

If this step behaves differently please verify your connection and firmware. If it continues stop using your printer and contact us or ask for help.