Extruder Temperature shows 635,60Deg after SW Update

K8200 3D Printer K8200 - Wiring and electronics
1

Hi,

I installed the Z-Axis Upgrade and the Glassbed on my K8200 but NOT the LCD/Controller (K8201). After updating the Software to 2.1.1, the Extruder Temperature stays on 635,60Degree Celsius (With different Repetier Host Versions tested). I also changed the Thermistor on the Extruder, changed Bed/Extruder Thermistor Plugs on the Board, no change.
Also when I unplug both Thermistors the Bed goes to 0 and the Extruder stays at 635,60Degree.

What could be the Problem?

Thanks, Michael