Help Adjusting pressure sensitivity

  • I got this reply from Tech Support:
    After checking you video,
    the following is the instruction from my engineer,
    the printer can complete the automatic leveling process in the video.

    1. Please adjust the adjustable resistance on the adapter board and adjust the sensitivity of pressure sensitivity.
    2. The pulley under the nozzle can be properly locked.
      Please see attached picture
      Looking forward to your reply
      Kickstarter Support
      Shenzhen Creality 3D Technology Co.,Ltd

    Does anyone know how to do this? Or where I could find the info or a step by step guide?

  • @shinmai I have broken 2 of the trimmer potentiometers by trying to adjust the E1 Vref. I was using small ceramic screwdriver and doing very small turns. The top piece that the screwdriver goes into, breaks off. Anyway to fix without having to buy a new board?

  • @UhOh-Crow you should check the voltage around the variable resistor to be better 1.55 and 1.7 volt.

    The ground control pin is the first from the top among the ones visible in the left top of the card.

    Check the creality video for the details

  • @UhOh-Crow

    What I'm wondering is whether the printer should be off when I test the white and green lines? Also, which do I touch the black and red lead to? And where? And should I set the dial to 200 ohms or 2000? I can't find an appropriate how to online. Any help, would be awesome.
    When turning the machine on, the blue light flickers a short moment and then then never turns on when I touch the hotend. No matter where around the screw I turn the Trim-pot. It will however in a certain position turn on completely and stay on. Not sure what to do.

  • @shinmai I think the temperature never increased.
    I've been waiting to get a multimeter after tech supports last response, but there explanation is thin on details. Here is what they said:

    The following is the hardware test

    1. First of all, restart the power and observe whether the blue light of the print head to the motherboard will keep the light state for a few seconds, and then go out.
    2. Remove the outer cover of the nozzle and check an adjustable resistor on the adapter board. For example, this adjustable resistor screwdriver can adjust the adapter board voltage, and the sensitive value of the varistor can also be adjusted and changed.
    3. Use a multimeter to measure whether the resistance of the varistor is 1kΩ. As shown in the figure, measure the green and white lines of the pressure-sensitive port.

    Feel free to contact us
    Kickstarter Support
    Shenzhen Creality 3D Technology Co.,Ltd

  • The red light is inside the optical endstop.
    Adjusting the strain gauge threshold shouldn't affect the hotend in any way, so the issue with the heater block not getting up to temp fast enough is a separate one. Are you getting correct temperature readings for the hotend, or is it showing something like -15?

  • @shinmai I don't think my adjustment were tiny enough. It is now giving me an error that it can't reach the right temperature in time so it locks on the error message. I'm going to try to find the sweet spot again, now that I see what you mean. Rereading your first message: I don't see any red light just the blue one. Should there be a red light also?

  • @UhOh-Crow Oh, I actually meant to replace the "trimpot" with the proper name: trimmer potentiometer. It's basically a small knob, that you "twist" with a screwdriver, in this case a #00 philips head IIRC.
    It'll look something like this:
    and be kind of tiny.
    I'll re-iterate again that you should adjust it VERY slightly. It has a lot of rotation, but the actual "workable" area of the full action is a tiny fraction of that rotation, so teeny-tiny adjustments are the way to go. It won't break or anything if you just crank it to one extreme or the other, but it's kind of a headache to find the "sweet spot" again after.

  • @shinmai
    Thank you so much. I don't know some of the words you wrote (like trimpot), but your explaination is so clear, I think I'll be able to figure it out. My first printer is an Ender 3 and I've gotten pretty good at diagnosing and fixing problems but these sensors are new to me and it's really difficult to find help online. Thank you for the help

  • It won't continue from the homing before ABL if your strain gauge isn't triggering correctly. So if the strain gauge threshold isn't properly set, it will get stuck driving the nozzle into the bed trying to "find" the bed.

    Before anything else, make sure your optical Z-endstop is working. There should be a red LED lit inside, which should turn off when you interrupt the optoelectronic sensor with something opaque.

    How to adjust the strain gauge threshold:

    1. Remove the hotend shroud
    2. Power-cycle the printer and wait for it to fully boot up.
    3. If the small blue LED on the PCB is off, move to step 4. If it's on, try turning the small trimpot on the PCB counter-clockwise in very small increments until it shuts off.
    4. Apply gentle pressure to the nozzle. If the small blue LED on the PCB lights up, you're good. If not, adjust it clockwise in very small increments until it fairly consistently turns on when you apply pressure to the nozzle, but still turns off after you no longer apply preassure

    If the above doesn't work, especially if the LED is either on all the time, or off all the time, try detaching the PTFE tube from the hotend to relieve the pressure it might apply on the strain gauge.

    "The pulley under the nozzle can be properly locked" I have no earthly idea what this means. I've literally taken apart my CR-6 SE to it's base components and put it back together, and I'm not even sure what part they're referring to, so good luck with that, hope the pictures they mention were helpful 😅

  • @UhOh-Crow -Also, they are incorrect, it does not complete the auto level. It presses down hard at the center and the software hangs, it never exits and never returns to home. It only releases after I turn it off.