LCD not working.

Discussion in 'Build Help' started by Greg Harker, Mar 22, 2016.

  1. Greg Harker

    Greg Harker Member

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    IMG_20160322_123108.jpg IMG_20160322_123540.jpg I have done the power on test and the LCD does not light up.
    The 2 fans on the base both came on. The PI has red and green lamps showing through the side of the base. I see the DC to DC has a red lamp on it. I am not feeling any heat issues (I physically touched the components).
    I have swapped the 2 cable positions.
    I did rotate the connectors when required.
    I tried the contrast on the LCD no difference.
    I have checked the wiring and it looks good to me.
    Does anybody have a suggestion on what to do next?
     
  2. Kick2box

    Kick2box Well-Known Member

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    Check the ribbon cables (put them out and do a complete measurement). They happen to have bad contact sometimes.
     
  3. Greg Harker

    Greg Harker Member

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    Ok I tried that they seem to be good. but the issue still persists. Thank you for the suggestion.
     
  4. Kick2box

    Kick2box Well-Known Member

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    You don't have a Ramps or a separate Arduino to test it? You could also use Repetier-Host or Pronterface via USB to test the printer without display.
    Edit: Just to be sure: viewed from the top, EXP1 of the display is left and right on the Rumba, that means, the cables have to be crossed. You meant that by "swapping the cable positions"?
     
    #4 Kick2box, Mar 22, 2016
    Last edited: Mar 22, 2016
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  5. Greg Harker

    Greg Harker Member

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    I am at my local Hackspace. I am going to wait for a few friends to some in that have prusa they are working on. we can plug it into that one. If it is the display I will grab one tomorrow.
     
  6. Spoon Unit

    Spoon Unit Well-Known Member

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    Did you rotate 180 degrees the ribbon connector points on the back of the LCD ?
    If so, try turning around the ribbon connectors on the rumba board.
     
  7. Greg Harker

    Greg Harker Member

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    Yes I did.
     
  8. Spoon Unit

    Spoon Unit Well-Known Member

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    OK. So try turning the connectors on the RUMBA.
     
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  9. Greg Harker

    Greg Harker Member

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    Good Idea, I tried rotating them again on the display but it was a no go. I put them back to the direction the instructions state.
     
  10. Spoon Unit

    Spoon Unit Well-Known Member

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    Still no joy?
     
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  11. Greg Harker

    Greg Harker Member

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    Not yet.
     
  12. Greg Harker

    Greg Harker Member

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    I tested the power on the lcd. the highest I could find was 1.7V. I tested the pins for the LCD on the Rumba and multiple pins are putting out 1.7V no higher. I suspect that the LCD requires a min of 3.3 if not higher.
     
  13. Greg Harker

    Greg Harker Member

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    I noticed that the jumper on my Rumna labeled USB power was set differently. I changed mine to be the same as the photo but it is still not working. I also notcied that the Drivers on the Rumba heat up very quickly so I turned it off.
     
  14. Greg Harker

    Greg Harker Member

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    I tried a new LCD display with jumper and cables in all possible combinations it still does not work.
     
  15. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    Connector EXT1 from the display must be placed in EXT2 in the Rumba, and EXT2 goes in EXT1. Did you do that ?
     
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  16. SoBaldrick

    SoBaldrick Well-Known Member

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    Rob, i have the same issue, looking at the build manual, it looks like the cables are straight left cable to left socket, but as you said, the left cable out of the LCD plugs into the right socket of the RUMBA, and vice versa.
     
  17. Greg Harker

    Greg Harker Member

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    By default no, but I have swapped them every time I have tested though. I changed the USB power jumper to match that photo but the drivers heat up quickly is this something I should be expecting. I did not want to run many test with the high heat if I was going to risk burning something out.
     
  18. K3LAG

    K3LAG Active Member

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    I had a problem getting mine working at first even though I was sure everything was correct. I plugged in the bed and then the display started working. After that first initial start up of the display it started working whether the bed was plugged in or not. I can't think of any rhyme or reason for that happening, but you might give it a try.

    Larry
     
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  19. Greg Harker

    Greg Harker Member

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    Thanks for that, I will try to out in a few days when I get a chance to work on the beast.
     
  20. Greg Harker

    Greg Harker Member

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    So I plugged in the heated bed and now the LCD display flashes when it is turned on. I solved the heat issue by unplugging the stepper motors, after noticing that they have locked when the machine is on.

    I still can not get the display to work though other than the quick flash when I first turn the machine on.
    I have also noticed that in the photos where the drivers are adjusted that the Rumba has lit LED's on it mine does not.

    Any other ideas?
     

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