The thermistor seems to be broken. That is a pretty common problem: the legs of the thermistor are very thin and brake off easily.
To test the motors, RAMPS and Atmega2560 you can flash
Rampstest and see if all hardware works.
If you want to test it with Marlin, you have to "home" the printer first or use
G92 X... Y... Z... to fake homing without endstops.
Then you can test X,Y,Z steppers but Extruder still won't run until you
allow cold extrusion
Edited 1 time(s). Last edit at 12/03/2017 03:53AM by o_lampe.