12864 LCD Maestro set up : Daig LED lights up and board resets

  • I’ve been trying to install an old 12864 panel I had lying around on my Maestro

    I’ve added M918 P1 E2 to my Config

    And connected the 2 ribbon cables

    The LCD panel doesn't light up (It appears the board version I have has the pedometer hidden so this might be an issue?)

    But when I turn the encoder the “LED diag” on the main board lights up and if I go too fast the board resets?

    I’ve unplugged the LCD & rebooted and it appears that everything still appears to work OK.

    Can someone confirm the LED daig should light up when the encoder moves and are there any other steps I need to take to get this working

    FYI I only currently have one file with text R3 C5 F1 T"Duet Maestro Self-Test" in 0:/menu/main atm

    Firmware Name: RepRapFirmware for Duet 2 Maestro
    Firmware Electronics: Duet Maestro 1.0
    Firmware Version: 2.02RC5(RTOS) (2018-11-28b1)
    Web Interface Version: 1.22.5

    Thanks in advance

  • administrators

    It sounds like incompatible pin connections to me. Are you sure you don't have the two cables crossed? But don't just swap them to see what happens.

  • Thanks
    I double checked that exp1 = exp1
    I remember from my smoothieware days that some MKS based boards had the connectors swapped 180 degs. I'll have a search around.
    Is there an easy way to check the pin layout of the LCD vs the Duet?

  • administrators

    I've heard that on the Ender 3, both connectors are swapped 180deg too.

    The pinout we expect is this, as on the original (badly named) RepRapDiscount Full Graphics Smart Controller:


  • @dc42 Thanks, using my limited electrical skills I have used the continuity test mode on my meter on the LCD board. The Beep pin is in the expected position for the buzzer, but on exp2 reset_ext its rotated 180 degrees (eg Pin 3 of P1 EXP2)

    I've ordered a new board on Prime as they are fairly cheap - I'll compare the two before installing.

  • @dc42 The new LCD arrived today and the pins on the new board were in the above orientation when I tested it with the meter, I plugged it in and it works perfectly

    I think the old one was an MKS one from Ailexpress and as you suspected the pins were rotated.

    It might be worth adding a warning on the wiki ensure others don't have the same issues (But in my case no long term damage was done)

    Thanks again for the support in solving the issue

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