I'm building a Prusa i3 which I've had some issues with. Some weeks ago, the thermistor on my E3Dv6 died for no apparent reason, and I ordered a new one. I also got a Ramps 1.4 today, so I started connecting things to try it out. The Ramps seems to work fine, the problem I have is that the temperature readings on the E3D are really strange. When I power the printer on, the reading seems fine. Setting the temperature higher makes the thermistor readings go up, but when the specified temperature is reached, the temperature either slowly starts decreasing or suddenly gets reported as 738,8 degrees, which seems to be some sort of standard faulty read value. I've also tried to do a PID autotune, but during that process the temperature takes like 5 seconds to go up one degree, and eventually the autotune fails with a timeout. I really can't figure out what the issue is. I would assume it would be wiring, if it wasn't for the fact that it actually does read temperatures most of the time.
I removed the heat shrink from the thermistor cables and checked the connection from the thermistor legs to the connector to the RAMPS. No problem there. Could the thermistor be broken (again)?
