Following on from the investigations into the properties of the extruder thermistor, the print bed’s temperature sensor was investigated. It too has been found to be an NTC thermistor.

Embedded at the rear of the print bed is the thermistor, it’s shown circled in green.

Connections for the print bed thermistor are beneath the print bed and consist of two female 3-pin micro-JST plugs with a two-way male adapter.

The plugs disconnect from each other relatively easily.

The same approach used in the extruder thermistor investigations were used for the print bed. The printer was set to Monitor Mode and known values of resistance were substituted for the thermistor. Next the “temperature” of the print bed was read from the LCD and recorded.

Two short lengths of tinned wire were pushed into the terminals of the female micro-JST connector to allow the IC-test clips to attach.

Once the results had been gathered a quick graph was made. Similarly to the extruder, the print bed uses an NTC thermistor as evident by the decreasing resistance of the thermistor as it is heated.

Feel free to make use of all the gathered results that have been saved in an Excel spreadsheet – Print_bed_thermistor_rev1. An ambient (25 degrees celcius) resistance of about 38k ohm looks likely.

In the event that the print bed thermistor circuit goes open circuit, the printer will display a print bed temperature of 3 degrees Celsius.

Print Bed Overtemperature – Fault 0013

A maximum print bed temperature of 120 degrees Celsius will be displayed. This equates to approximately 20k ohm. Like the extruder, if the Da Vinci reads a maximum print bed temperature for more than 30 seconds then the printer goes into Fault 0013.

The user manual says that a fault 0013 is, “The temperature of print bed reach to warning range limited”, that is, the print bed has exceeded its maximum temperature. Turning the printer off and on again clears the fault.

For more ways to improve your Da Vinci prints, check out the Tips and Tricks page.