MINTEMP BED error

Discussion in 'Calibration, Help, and Troubleshooting' started by Alex9779, Mar 11, 2016.

  1. Alex9779

    Alex9779 Moderator
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    Hi guys,

    ok DONE!
    So I got the first real problem: I did the power on test while the bed was not connected an saw that error as described in the manual.
    Then I was curious and plugged in the bed but the error stayed.
    So I waited for my replacement corners to be built and when they were ready I fully assembled the printer.
    But when I power it on the error is still there.
    I measured the cable (red/black) to the PCB but it is totally fine.

    What can I do?

    Alexander

    IMG_0199.JPG IMG_0200.JPG IMG_0201.JPG
     
  2. UlrichKliegis

    UlrichKliegis Well-Known Member

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    No mix up of hotend and bed sensor connectors?
    Marlin configuration matches the two different sensors?
    Did you plug in the bed sensor with the power on or off? (Should normally do no harm, but...)
    Wrong connector (I call it experience when I recognize an error after making it for the third time)?
    I see you have a multimeter on your table. Did you measure the sensor resistance?
     
  3. Alex9779

    Alex9779 Moderator
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    1. No, the PT100 connectors are totally different than the bed sensor, so I am sure I did not mix up...
    2. I uploaded the firmware built from the latest commit on the github repo for the dual (built it myself)
    3. Off, then on then off, replugged, restarted, replugged while on..........
    4. THB on the RUMBA, I double triple checked the orientation, dunno if it really matters at all...
    5. I measured the cable for conductivity, it is fine: red 0.7, black 0.8 Ohms resistance. I am not able to measure a resistance between red and black when connected to the PCB...
     
  4. Greg Holloway

    Greg Holloway Administrator
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    Hmm, sounds like a dodgy connection on the PCB. Can you take off the bed PCB check the soldered contacts (the print cover should pull off) and if its no good fire off an email to support@bigbox-3d.com with your order number and I'll get a new bed sent to you.
     
  5. Alex9779

    Alex9779 Moderator
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    Oh Greg, just wrote an email to support... So just ignore it for the moment...
    I tried the firmware with the PCB deactivated. All other things run fine so far...

    Will check the solders contacts...
     
  6. Greg Holloway

    Greg Holloway Administrator
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    @Alex9779 I see the mail, let me know how it goes.
     
  7. Alex9779

    Alex9779 Moderator
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    Ok here are the contacts
    IMG_0202.JPG

    I measured them directly, again in the max range go 20M Ohms nothing...

    What must be the resistance?
     
  8. Greg Holloway

    Greg Holloway Administrator
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    I get around 130 on the two beds I tested. We'll send out a replacement.
     
  9. Alex9779

    Alex9779 Moderator
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    Ok thanks, so this is SOLVED here :)
     
  10. Alex9779

    Alex9779 Moderator
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    And here we go! I have a bed temperature reading!
    IMG_0205.JPG
    Thanks Greg for the quick replacement!

    Now up to join the fun of clogged nozzles, filled up filament dump buckets, failed prints and....... Was there something else? Oh yes: good quality working parts! :D
     
  11. Sgllama

    Sgllama Active Member

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    I have been having a similar issue :-(

    I ran a PLA pre-heat via the LCD, mainly as a test of the wiring and things seemed to go pretty much ok - OctoPi graphed a nice rise in temperatures, then I let the Rumba control the cool-down. Next day, MINTEMP errors. Much fiddling with multimeters later, checking my wiring, I've worked up the cables and now have the cover off the heated bed's connector: only reading an open circuit for the thermistor direct to the solder joints on the back of the connector.

    I'll be sending an email to support...
     
  12. jet

    jet Well-Known Member

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    I'm also getting MINTEMP BED on my freshly assembled v1.1 hybrid. I'll contact support, but I'm wondering if this is related to the missing LED and resistor on my bed.
     
  13. mike01hu

    mike01hu Well-Known Member

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    No one has the LED fitted and it would not have any effect anyway. It sounds like an incorrect connection so do check your connections for the thermistor to the Rumba and to the bed.
     
  14. jet

    jet Well-Known Member

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    Whoops, my updated post went missing. I checked the board and there's no connection through the thermistor, so I've contacted support for a replacement. The missing LED and resistor caught my eye because power can't travel through a broken circuit.
     
  15. SandervA

    SandervA Member

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    Hey guys,

    I seem to have a similar issue as described by Alex above; when I start my BB-dual hybrid it displays MINTEMP BED and also both extruders are showing 0oC. When I then disconnect and reconnect the the cable for the extruder PT100s, I get the right temperature (around 23oC at the moment, which reacts to external heating of the hotend). However, the bed temperature stays 0oC. I measured the resistance of the bed sensor at the end of the cables plugging in the RUMBA; at 23oC, it is around 100-115 kohm. I measured the 2 terminals of the RUMBA board, which indeed put out 12V. Anybody got an idea what could be the issue?

    Many thanks in advance,
    Sander
     

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