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Solved Another Problem with Heat Bed

Discussion in 'Troubleshooting' started by Taylor, Apr 3, 2015.

  1. Taylor

    Taylor Member

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    Ok so when I first got the printer I the heat bed wouldn't work,It just showed 0 for the temperature,After taking it apart and wiggling a few wires it worked and stayed working for a long time. Every once in a while I noticed the bed would show 0 and cool down and eventually kicked back on. Now all it reads is 0 and I cant figure out whats going on. I have traced all the wires back to the ramps there all connected properly,I swapped the thermistor on the bed for a new one still a no go,I checked if there was any shorts and all is good. I dont know where to go from here. The extruder shows temperature and can heat up with no problem. I dont know if the RAMPS is going bad or if there is a short. Any help at all would be great. Thanks!
     
    #1 Taylor, Apr 3, 2015
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well, zero degrees is either a bad thermistor a bad wire or a bad RAMPS*

    I'd run an entirely new wire and thermistor in there. First solder the thermistor to a new run of wire and then read the resistance of it with a meter and make sure it is not shorted or opened (close to 100k is correct). Plug it onto the RAMPS and see if it (the software you are using) still reads zero. If it does then it is probably a bad RAMPS. Otherwise run it from the ramps to the bed.

    It is remotely (very remotely) possible that the firmware is corrupted or the Arduino flaky. Reloading the firmware is easy, replacing the Arduino would be the very last thing to consider.

    *(that last is unlikely)
     
    #2 mark tomlinson, Apr 4, 2015
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Swapping the thermistor requires care as the normal thermistors are easily damaged. So even swapping it you may have simply replaced the problem. That is why I suggest testing it before installing it.
     
    #3 mark tomlinson, Apr 4, 2015
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  4. Taylor

    Taylor Member

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    Mark,You nailed it right on the head. I first took the bed of my other Robo and connected it to the Robo in question and what do you know it works. So of course it had to be the wire,I replaced the wire like you suggested and IT WORKS!!!! lol

    It looks like crap,Will Robo have to replace the whole bed or just that one wire? The cable I used to replace it looks like crap and I don't trust it lol

    Also the thermistor was glued on with a Red Flexible glue,What is that? It was such a pain to take off.

    Thanks again!
     
    #4 Taylor, Apr 4, 2015
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  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    It was probably a high-temp epoxy or RTV (like for car engines--it is rated pretty high).

    I am not sure what Robo would do to replace it. They could just send you a new thermistor and leads. If you request just the thermistor and wire that might be what they send. Worth a shot.

    If you used any wire thicker than the thermistor leads it is probably fine -- at least as far as wire size goes, not your solder/wiring job :)
    The thermistor does not have to handle any real current.
     
    #5 mark tomlinson, Apr 4, 2015
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  6. Taylor

    Taylor Member

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    If I was a betting man,It would fail at the soldering points. lol Im slowly learning but still a complete novice.

    At Least it works and gets me by until I can get the proper parts. Thanks again for the help!
     
    #6 Taylor, Apr 4, 2015

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