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Hotend not heating up properly.

Discussion in 'Troubleshooting' started by Mater, Jul 1, 2017.

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  1. Mater

    Mater New Member

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    This started a few days ago. My hotend gets extremely hot to the point where it's burning the filament and smoking.
    I set the temp to 200 and from what the LCD and Octoprint display it slower then normally gets hotter but the hotend is getting much hotter than what is displaying. Once it gets to 175 I extrude filament thru and it comes out very thin and stringy along with the occasional puff of smokes, it also smells like its burning. It seems like the hot end works fine because it is getting hot, but it's not reading the right temperature. When I turn the printer on the default temperature is 125 according to Octoprint and the LCD.

    I also had an issue with my print bed not heating up due to the pogo pins on the board not spring back to there original positions. I recently got a new pogo pin board from Robo and installed it and the bed works great, but now I have this hotend issue. Could this be a thermistor issue or is there a setting somewhere that may have gotten changed?
     
  2. Geof

    Geof Volunteer Moderator
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    Check your thermistor and connections. Sounds like its lose not reading correctly, or bad.
     
  3. Mater

    Mater New Member

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    I'm thinking its a thermistor issue. I've tried unpluging and plugging back in all the connections related to the hot end. I tried heating it up again and it got up to 184.8 and then I got a connection interruption message on the LCD with an error message. Here is a screen shot of the log with the error. I originally though this error was related to my print bed. It seems like with my bed and the hotend went bad at the same time.

    upload_2017-7-1_14-22-43.png
     
  4. Geof

    Geof Volunteer Moderator
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    Sounds odd. Id ping robo support for assistance. Sorry i dont have an r2 so cant be much help
     
  5. Mater

    Mater New Member

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    I spoke with someone from Robo today. They said it may be a bad thermistor wire so there sending a new one out. I'm not 100% convinced this is the issue. I also have a C2 so after I got off the phone with them I changed out the hot ends, putting the C2 in the R2 and vise versa. The C2 heated up just fine to 200 and R2 still seemed like it was overheating. So this would rule out the Thermistor wire.

    If I remembering correctly, when turning the R2 on I usually had a default start temp of around 25. Now when it first gets turned on it is at 125. Is it possible that the default start temp changed somehow? This seems extremely odd.
     
  6. colton81

    colton81 Active Member

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    Have you tried re flashing the sd card with the R2 image? It could be a corrupted image


    Sent from my iPhone using Tapatalk
     
  7. colton81

    colton81 Active Member

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    Also when it states that its at 125 is it actually hot or is the nozzle cold? Could test with a laser temp gun or just get a piece of pla and touch the tip of he nozzle to see if it softens at all.


    Sent from my iPhone using Tapatalk
     
  8. Mater

    Mater New Member

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    I don't have an R2 image. How would I go about getting one?

    I tried setting it to a couple different temps. When it's first turned on and comes up 125 it's consistently cold, even after setting it to 120 it says cold. Once it's set to about 126-127 it starts to heat up, at 130 it melts PLA.
     
  9. Kilrah

    Kilrah Well-Known Member

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    Weeeelp I power up my R2 this morning and have a similar issue.
    Extruder temp 13.7°C (moves a bit around it) instead of the ~25°C it normally reads when cold and which the bed does correctly.

    No significant temp change when heating, heating however works correctly.
    Disconnecting the whole head ribbon cable makes no change to the reading.
    Disconnecting bed now reads about 15° when it would normally read 0 (printer board sends -40).

    No time to troubleshoot further right now.
     
    #9 Kilrah, Jul 3, 2017
    Last edited: Jul 3, 2017
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    It rules out the thermistor only. Not the wiring inside the extruder.
     
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  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Contact Robo for an R2 image they should have one available.
     
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  12. Kilrah

    Kilrah Well-Known Member

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    I found some time and unfortunately everything is OK up to the mainboard. So something on it has failed. I also get 40 Ohm on the temp input, which doesn't seem correct (bed input is a more normal 2k).
    Connecting the extruder thermistor to the bed input reads correct, opposite doesn't.

    Tried 2nd extruder input and it also doesn't work.

    Time to contact Robo. :oops:
     
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  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Bed an hotends use 100k thermistor but trying to read that through the harness is not really effective. Still you have proved the problem by swapping inputs :)
     
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  14. Mater

    Mater New Member

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    To help troubleshoot some more I switch the ribbon cables coming out of the top of each printer, I plugged the C2 into the R2 print head and the R2 into the C2 head. The R2 still booted up with a temp of 125 and the C2 started with 25. So there is nothing malfunctioning in the print heads. The issue has to be the with something below the deck.

    Tech support seem to think is an issue with the Robo board so there sending me a new one.

    I've asked repeatedly for an R2 image and they seem like they don't want to send me one. For whatever reason all of my requests for one keep being ignored.
     
  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Until quite recently they had no images to send you. We spoke with @Jerry RoBo 3D recently though and he had indicated they were going to be providing support with that ability. In the interim you can get an image from someone on here and just be sure to change the machine name.
     
  16. Kilrah

    Kilrah Well-Known Member

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    I sent an email detailing all my issues, troubleshooting and current status but it seems it must have been too long... I got no actual text reply, just received an order for a free pogo pin board to accept with no comments at all. Yup thanks that was the first issue for which I have a workable interim solution, but the real one is the temp problem right now.
     
  17. Mater

    Mater New Member

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    That's good to know, no one explained that to me. My request and questions just went unanswered and ignored, which is very frustrating.
     
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I have not yet heard of a case where someone actually GOT an image from them so... I consider it a work in progress until we know it is happening :)
     
  19. Kilrah

    Kilrah Well-Known Member

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    There is close to 0 chance this has anything to do with the Pi image.
    If you see a temp in octoprint other than 0 then it's getting it from the printer control board and was sent that way, period.
     
  20. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Pretty much. While it is possible there is an issue with the Pi communications to that board it is not likely. There would be a lot of other inconsistencies in that case.
     
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