Tightening the Hotend (Heating not working... plus...)

Discussion in 'Build Help' started by Old_Tafr, Mar 25, 2016.

  1. Old_Tafr

    Old_Tafr Well-Known Member

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    Just at Tightening the Hotend stage of commissioning after setting X Y and Z home etc.

    I can set Hotend "1" to 285 on-screen but it says Hotend 2 is increasing in temp.

    Both fans start at 40oC (should BOTH start?)

    Hotend 2 got to (on screen) 195 ish then got a "heating Failed" message.

    Using a laser temp sensor thingy NEITHER block that holds the nozzle appeared to be above ambient.

    Placing my hand behind the hotends air is COLD coming out.

    BOTH fans stop when temp drops to 40oC (as expected)


    .Just about to check the voltage on HE0 and HE1 pins on Rumba to see which if any have volts but as I have tried Hotend 2 and Hotend 1 (on screen) heats (set to 60) but it runs away way above 60 and keeps going and then I get Heating Failed then I don't want to have it switched on too long as although I can't feel or measure heat from outside something is heating and causing fans to start.

    Possibility is that I have the temp measuring thermistors the wrong way round as something appears to be heating.
     
  2. Alex9779

    Alex9779 Moderator
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    Maybe you switched the heaters or the PT100 connectors?

    Yes they share the same PIN.
     
    Mike Kelly likes this.
  3. Old_Tafr

    Old_Tafr Well-Known Member

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    Checked the heater wires and thermistor (PT100) these look good, considered swapping the PT100 but as wiring looks good then it may fix it but it would not explain the 1=2 error. Then I looked at the connection TO the PT100 boards. I have them the wrong way round.

    Just trying to access them to swap.

    Sorted.
     
    #3 Old_Tafr, Mar 25, 2016
    Last edited: Mar 25, 2016
  4. Mike Kelly

    Mike Kelly Volunteer

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    If you enable heat on 1 but 2 turns on then you have the wires swapped for the heaters

    Do a sanity check to see which one's actually hot
     
  5. Old_Tafr

    Old_Tafr Well-Known Member

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    The crossed wires were the connection from Rumba to TP100 boards, as above once changed all worked fine. I tried setting various temperatures in steps up to the 285 required and each time it overshot slightly by a few degrees and then stabilised. The correct nozzle indicated the heat on the display this time.

    Interestingly my laser temp reader device didn't register any increase on the Al block with heater and thermistor even when I pointed it at the heater itself at the back of the nozzle. Pointing it at the plate on the gas cooker worked fine, maybe the emissivity of the Al block prevents this; equally the heat was evident in the breeze from the fans. Not being keen on blisters I didn't touch the nozzle.
     
  6. Stefan

    Stefan Well-Known Member

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    As far as I know these laser temp thingys have a measuring field like a 5-10 cm circle, not like the 2 mm of the red laser pointer dot used to aim.... should be mentioned in the manual
     
  7. Kick2box

    Kick2box Well-Known Member

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    The emission of polished aluminium is to low for a cheap IR-thermometer.
     

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