Hot end temperature is showing without any thermistor. Attached photo is self explanatory. I'm using Mega2560 + Ramps 1.4 combination with Marlin-2.1.x. I have replaced ramps 1.4 to 1.6 and tried again. However, still it showing temperature. Further, i tried different pin i.e 15, then it worked fine for ramps 1.4 & 1.6. But it is showing 58°C / 73°C with pin 13 & 14 respectively without any thermistor
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Thank you
You'll get some temperature display regardless of a connected sensor. If you want to drop that display then change your project accordingly.
Did you replace the thermistor with a piece of solid copper wire? Otherwise you have a floating input to the amplifier.
Hi Paul. Thank you for your time. Actually I tried to short a pin and it now showing 100•c.
Do you get the same response with a different amplifier?
Yes!!
Then you have shown that the input of your system is not the problem, so time to debug the next part. Of course, none of your tests relate to actual temperature, but are measuring the effects of that heat, the voltage generated by the thermocouple.
So , where in your system does the voltage of zero get distorted into some positive value? Quite possibly in software.
