heater temperature drops to 0

[raynelang]

Hello!

Been printing with the m2 for about a year now, an just hit a problem I have not had before.

With the printer sitting idle the heater responds with 21 degrees. Using the graph I have monitored this temperature and it stays at 21 for 10 minutes without any flickers. I then moved the heater cables and connection by hand and still did not see any flickers in temperature. Then I move the printer head and bed around, still a solid 21 degree reading. I then set the bed temperature to 60 for printing and it heats up without issue. Heater still reads 21 degrees.

Then I set the heater to 215 degrees and the heater temperature starts to rise but once it reaches 30-40 degrees it immediately drops to 0 and the program automatically errors and turns the heater off.

To me it does not appear to be a wiring issue. Anyone else had an issue like this? I wondering if someone had a good test I could try to isolate the problem being the sensor or the ramps board.

[raynelang]

I was able to figure this out. It was a bad sensor. I ended up touching the extruder nozzle to the heated bed and turned on the heated bed to 60 degrees. The extruder started out reading 21 degrees and as it climbed up to 40 degrees it dropped down to 0.

[jsc]

I would see if you can detect any breaks in the wires to the thermistor, the temperature sensor in the heat cartridge. That is the most common point of failure.