HI , i am ashok . i am facing one problem with 3d printer. initial condition of hotend temperature is not giving room temperature..instead of showing room temperature it is showing like this 250 C and some times it's showing above 250 C .
i have checked the resistance of thermistor ends also it is giving near to 100k..




i am not able to find out the problem please me.

and i am using ramps1.4 and marlin firmware

There are 6 possibilities

1) the thermistor or shorted
2) the thermistor cable is shorted
3) the analog port on the mega is dead.
4) the firmware is looking at the wrong port
5) you have plugged the thermistor into the wrong place
6) faulty ramps board


has it ever worked?

you say you measured the thermistor and it reads 100k. Was that threw the cables? Ie unplug from the ramps and measure threw the cables and the thermistor?

Where did you plug the thermistor into? It should be plugged into T0

what did you set as the motherboard in firmware? Should be "#define MOTHERBOARD BOARD_RAMPS_13_EFB"

have you edited any pins.h files?

If you remove the ramps and the thermistor cable and measure across the two T0 pins, is there a short?

Edited 3 time(s). Last edit at 10/26/2018 07:35PM by Dust.