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Solved Hotend temp is not registering

Discussion in 'Troubleshooting' started by ColoradoBob, Jul 6, 2016.

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  1. ColoradoBob

    ColoradoBob New Member

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    O.k., so this has been weird for me so I'm turning to all of you for help.

    I've had my printer for about 5 months and things have been great. I had a particularly gnarly clog I had to clear and in the progress the rubber boot tore off of the hotend. Being somewhat of a noob I didn't think much of it.

    However, my prints started acting up and stopping mid-way through and I would get a communication error in OctoPrint. After researching a bunch I determined it was likely a loose thermistor, so I checked it and sure enough it was loose. I put some Kapton around the head to hold it in place, no joy.

    So I got a set of new Thermistors and installed one, no joy.

    What is happening now is that the temperature of the hotend in OctoPrint (and in Mattercontrol, and Cura, I've checked them all), it shows the Hotend at 143.0C and does not change, whether I turn the hotend on or off.

    When I turn the hotend on, it does heat up, but I can't get a temperature register, again in any of the three softwares.

    Any idea?
     
    #1 ColoradoBob, Jul 6, 2016
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Temperature readings are via the thermistor (which you replaced) via the RAMPS and the Arduino.
    The most normal cause of issues is a bad thermistor (they are fragile and easy to damage). If the thermistor is good then that leaves the wiring, the connectors, the RAMPS and the Arduino.

    With the power off read the resistance of the thermistor from the connector that plugs into the RAMPS back to the thermistor (disconnect it and read OHMS). It should be ball-park 100k ohms.
     
    #2 mark tomlinson, Jul 7, 2016
  3. ColoradoBob

    ColoradoBob New Member

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    Thanks Mark,

    I Ohmed out the Thermistor and it seemed okay. I traced the wire back to the RAMPS board and it looked okay, but I unplugged and plugged it back in to see if it would help.

    It looks like my temperature reading is working correctly now, but after putting everything back together, the Extruder gear is now acting like it's jammed, so I'll probably disassemble and reassemble it again to see if I did something wrong.
     
    #3 ColoradoBob, Jul 7, 2016
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  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Good work!
    Make sure you are not trying to extrude at to low of a temp. I forget what the MIN TEMP is in the firmware, but too cold and it will not let the extruder move filament.
     
    #4 mark tomlinson, Jul 7, 2016
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  5. ColoradoBob

    ColoradoBob New Member

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    Thanks,

    I've been using 210C for extruder and 75C for bed with PLA, been working great.

    I finally got it sorted out. There was a broken wire at the plug on the step motor. I had to buy a new step motor just for the plug and the colored leads were in a different order on that NEMA 17 motor.

    Everything seems to be working great right now, I'm running a test print and it looks great so far!

    Thanks for the help!
     
    #5 ColoradoBob, Jul 7, 2016
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