Temperature sensor not working

[Copia11 0]

I have an Ultimaker Original (not plus) and the temperature sensor won't work. It always thinks the bed is at 100 degrees, even when the bed is cool to the touch. The heating table is aftermarket, but I don't know where it's from. I checked for broken wires or loose connections, all is in order. What should I do?

[gr5 964]

Did you change the firmware? If you did then see if you can get the original firmware that the previous owner was using. And any other information about how the heated bed sensor works (like what kind of sensor it is). You can rebuild the firmware for many different types of heated beds but first you need to know what kind of temp sensor it is. Also consider heating it with your hands or a hair dryer (the sensor - not the entire bed) and seeing if the temp reading changes a bit.