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Answered HELP: Hotend and Bed Thermistors Reversed

Discussion in 'Troubleshooting' started by Oliver Ni, Oct 25, 2017.

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  1. Oliver Ni

    Oliver Ni New Member

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    A couple of weeks ago, I disassembled the hotend in order to change thermistors. After putting it back together and trying to print, I got Error MAXTEMP messages. In order to investigate this, I removed the thermistor from the hotend and held it between my fingers to look for a temperature response in the Matter Control "Controls" panel.

    What I noticed is that the hotend thermistor was outputting bed temperature readings. That is, when I held the hotend thermistor, the "Bed Temperature" would display my body temp, and the "Extruder Temperature" would display ambient room temperature. This was the cause of the error message: the printer thought that the bed was getting too hot, when in reality the hotend was performing as normal.

    Does anyone know of this problem or how to fix it? Thank you.

    PS: The attached picture shows the Control Panel display for the following configuration:
    • Extruder Thermistor in hand so as to read body temperature (This is shown as the "Bed Temperature" reading in the picture)
    • Bed preheating to 90 deg C (Temp on the rise when screenshot was taken. The bed temperature is shown in the "Extruder Temperature" reading in the picture).
    upload_2017-10-25_20-46-14.png
     
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    The two connectors are identical on the R1 just swap them and the thermistors should read correctly.
     
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    At the RAMPS board just to be clear.
     
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  4. daniel871

    daniel871 Well-Known Member

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    If they're still using the same connectors in the bundle above the carriage, you could do it there as well.
     
  5. Geof

    Geof Volunteer Moderator
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    bed thermistor isn't up there :D
     
  6. daniel871

    daniel871 Well-Known Member

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    Maybe not on the R1 *you* got.
     
  7. Geof

    Geof Volunteer Moderator
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    Your bed wires ran from the bed up to the carriage then back down to the ramps board?
     
  8. daniel871

    daniel871 Well-Known Member

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    From the bed to the hole over by the Z-axis and down to the Ramps (so that the bed couldn't move it's full length of travel without binding the wires), I'm just being a smartass about how poorly managed the wiring system was back when I got mine.
     
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  9. Geof

    Geof Volunteer Moderator
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    Gotya :D
     
  10. Oliver Ni

    Oliver Ni New Member

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    I'll give it a shot, thanks! Still trying to figure out how they became reversed in the first place....
     
  11. Oliver Ni

    Oliver Ni New Member

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    Thanks for your help everyone. I switched the plugs on the board and it fixed the problem. I guess I'll never know how they got switched.
     
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  12. Geof

    Geof Volunteer Moderator
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    Glad you got it going again, I'm going to close and lock the thread. Any other issues spring up dont hesitate to start a new thread! happy printing!
     
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