I've got an early Robo3D's and getting an extruder temp reading of 357.5* upon start up. Is there a way to know if the problem is the hot end or the thermistor? (I have one of the early Kickstarter printers with the ceramic hot end). I've removed the hot end and cleaned and reconnected all the wires, same error message. If it is the hot end can anyone recommend a good replacement? I've found some online, but they are about $100. At that price I think I'd just replace the whole printer with an Ender 3. Thank you.