Duet Differential height sensor LED doesn't light



  • Hi,

    After some help. I have just fitted the Differential height sensor to my Anet A8 Printer. The mother board has been upgraded to a MKS Gen v1.4. I have connected the sensor up as per the instruction in here: https://miscsolutions.wordpress.com/mini-height-sensor-board/

    The sensor works fine and detects the bed, but the LED light does not work at all. Not when the printer powers up or when the the bed is detected. I know it does not effect the function of the sensor, but it is handy to know when the senor is detecting.

    I purchased the sensor from e3d & they have told me to ask for help on here to see if it is a simple fault before they go down the warranty route.

    Thanks, Kevin.


  • administrators

    I'm sorry that your IR sensor appears to be faulty. When testing IR sensors prior to release, I have occasionally found one with an LED that does not light. The cause has always been one of the following:

    • One end of the LED not soldered properly to the PCB
    • The plastic top of the LED has been sheared off
    • (very occasionally) the LED is missing completely

    The only other likely cause is a missing or improperly soldered 330 ohm series resistor, but I have never encountered this.

    If you can see that one end of the LED is not properly soldered, and you have a fine-tipped soldering iron, then you could attempt a repair yourself (and if you fail, we will still honour the warranty). Otherwise, please ask for a warranty replacement, which I hereby approve.



  • @dc42 Looks like the plastic top of the LED is damaged. alt text The image is a bit blurry but you can see part of the white missing at the top.

    E3D are saying the unit will need to be returned with recorded postage so you can review the board. Is this still the case? With the current situation with COVID-19 I dont know when I will be able to get to a post office to send it back.


  • administrators

    @KB87 said in Duet Differential height sensor LED doesn't light:

    @dc42 Looks like the plastic top of the LED is damaged. alt text The image is a bit blurry but you can see part of the white missing at the top.

    E3D are saying the unit will need to be returned with recorded postage so you can review the board. Is this still the case? With the current situation with COVID-19 I dont know when I will be able to get to a post office to send it back.

    Normally we ask for faulty boards to be returned, but I will make an exception in this case. So you don't need to return it.



  • @dc42 Thank you very much for your help on this issue 🙂


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