I have a confusing problem with the two temperature sensor inputs.
The value is wrong. I checked the inputs without NTC and here the values:
Therm1/open and Therm2/open -> Therm1=30,7 / Therm2= 0
Therm1/close and Therm2/open -> Therm1=736 / Therm2= 99,6
Therm1/open and Therm2/close -> Therm1=32,4 / Therm2= 736
Both inputs affect each other.
If the Extruder is cold then the Heatbed value seems to be correct but if the temperature of the extruder rices over 60 degree the heatbed temperature rises too.
I checked the NTC of the extruder. It has a resistor value of about 400 Ohm by 190 degree.
Check if the thermistor has around 100KOhms at room temp.
Also check your wiring.
It sounds like one or both thermistors are shorted to the chassis or together.
Make sure the hotend thermistor is correctly isolated against the heater block.
Otherwise it might electrically connect to the hotend heater!
Yes, the thermistor has got the right value according to datasheet.
All displayed temperature values were without any NTC connection to the board.
The connectors were open (nothing connected) or close (bridge between pins)
I think the board is the problem or the firmware possibly the parameter settings.
Any ideas about this behaviour ?
Disconnect the board from power and check the resitors at the THERM ports.
They should have both 4.7 k Ohms.
Also check with a meter if there is connectivity between the pins of therm1 and therm 2.
There should be no connect between them except for the GND line.
I measured between the Therm1 connector pin and +5V and Therm2 connector pin and +5V. Not the pin which is connected to GND. The values were 0,2 Kohm and 4,7 kOhm.
Finally between Therm1 and Therm2. There was the value 4,9 kOhm.
Thanks.
