Temperature problem  

Re: Temperature problem

Yes, it's physically impossible for the heater block to fluctuate as rapidly as your video shows - so that does indicate a bad connection. The fact that the temperature drops from nominal means that the overall electrical resistance of the connector + wires + thermistor increases, which is perfectly consistent with either a loose connector or a wire that's almost completely broken.

Since the only connector in the thermistor circuit is inside the electronics enclosure, it is probably not moving around, which pretty much brings us to the conclusion that your wire is suffering fatigue failure. Look for a place in your wiring harness where the wire is being bent back and forth sharply. (If you built the printer from a kit, did you successfully follow the instructions about the 3mm filament being anchored in the Extruder body? This is part of the design to assure your cables don't get bent sharply right where they leave the anchor point on the extruder.) For what it's worth, some people (myself included) have replaced the spiral wrap on that cable bundle with a braided nylon cover - which seems less likely to abrade the wires. But the 3mm plastic filament is still needed to "stiffen" the bundle and keep it from bending sharply.

Re: Temperature problem

I had the same problem. As soon as the Extruder started to move i had fluctuations up/down 40 degress. Several Thermal Runaway Errors during printing. Like Jay said the real Temp can't jump that fast. After I pushed the Thermal Sensor inside of the Thermal Block more towards out, the problem disappeared. Anyway I guess the sensor is damaged. I my other post I am triying to find out which sensor and where I have to buy. Till now I dont have any idea.

Re: Temperature problem

Thank you both for the reply. After chatting with support they have sent me a new thermistor cable. Free of charge. Hopefully this solves it.