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Unanswered MEGA 2560 R3 replacement

Discussion in 'Troubleshooting' started by PTIschool, Mar 5, 2021.

  1. PTIschool

    PTIschool New Member

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    Looking for a replacement mega R3 board because I think I fried mine when trying to resolder the data cable connector because it became loose. Seems like I have had this problem with the nanos also. Don’t understand why a small solder would knock the board out. Any help would be appreciated. Thanks.
     
    #1 PTIschool, Mar 5, 2021
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    #2 mark tomlinson, Mar 6, 2021
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  3. PTIschool

    PTIschool New Member

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    So I bought the mega replacement and put it in my machine, but my lcd is still showing the hotend at 192 even though its not even plugged in. Any ideas?
     
    #3 PTIschool, Mar 8, 2021
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Bad thermistor or bad wiring/connection in the line to the thermistor.
    If the thermistor is reading too high or too low remember this:
    The ones Robo uses are NTC thermsitors (negative temperature coefficient.
    This means that as the resistance goes down the actual temperature is going up (and vice-versa).
    With it reading high at room temperature that means the thermistor is shorted or there is an short circuit in the wiring (lower resistance => higher indicated temperature).
     
    #4 mark tomlinson, Mar 8, 2021
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  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Honestly with most Printer sensors -- if you think the electronics is the problem it is most likely the RAMPS board and not the Arduino.
    I have seen some Arduino failures, but that is not the most common component (the RAMPS is the most common failure).
     
    #5 mark tomlinson, Mar 8, 2021
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  6. BrooklynBay

    BrooklynBay Active Member

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    Swap the hotend & bed temperature sensor wiring on the RAMPS to see if the reading changes or remains the same. This will help you troubleshoot the issue if you don't have a spare temperature sensor to test with.
     
    #6 BrooklynBay, Mar 9, 2021
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