Hot end temperature is showing without any thermistor. I'm using Mega2560 (Mega WiFi R3 Atmega2560 NodeMCU ESP8266 32Mb Memory USB-TTL CH340G) + 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..