Converting from a Lerdge board...newbie question galore!



  • Howdy all! Just ordered a Duet 2 wifi and a panelduo to replace the Lerdge board on my MonoPrice Delta Pro. I'm a Mechanical by training...so sparky things scare me a bit but I'm trying.

    I was thinking I'd try to make some patch/extension cables to connect up the Duet without cutting any existing cables. The Duet comes with it's own connectors so I'm good on that end. What I'm struggling with is sourcing the connectors equivalent to what's found on the Lerdge board.

    I know this isn't exactly what this forum is for but hopefully it's not too offensive to try. Do any of you have a good resource or tricks for figuring out part numbers for existing connectors? I went over to digi-key and got a little lost...

    If it helps I've got a photo album of the existing connectors here. (please forgive the inch calipers 🙂 )



  • @tgarr

    All the Lerdge X cables can be purchased from Ali Express they may list the connector type some are DuPont some are Molex ..personally would not go the patch route just another level of complexity and the Duet is not cheap but the replacement cables are.

    hope this helps


  • administrators

    The 4-pin square ones look like Molex Microfit 3.0 except that genuine molex ones would be black.



  • @Carlo said in Converting from a Lerdge board...newbie question galore!:

    d from Ali Express they may list the connector type some are DuPont some are Molex ..personally would not go the patch route just another level of complexity and the Duet is not cheap but the replacement cables are.
    hope this helps

    Those look like jst connector, the female one are pinned for soldering onto boards. Its cheap to replace the jts male side, so unfortunately your just better off snipping them and putting the duet connectors or if want cut them higher and crimp dupont connectors to make them interchangeable . If you do snip them and want to go back just buy the jts male connectors and re crimp them. Oh and make sure you have a voltage meter to test the polarity of the power leads powering the board , i noticed there all the same color. If you do end up putting on the duet connectors make sure you get a good crimp tool, the cheap ones on amazon make really bad crimps and make the job 10x harder lol.

    check these out or get something similar i forgot how pricey it was
    but i guess i was super annoyed with the standard one.

    https://www.amazon.com/gp/product/B002AVVO7U/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

    these look similar
    https://www.amazon.com/IWISS-Crimping-AWG28-20-Terminals-Connectors/dp/B078WNZ9FW/ref=psdc_553392_t2_B002AVVO7U



  • Square 4 pin one might fit the readily available ATX 4 pin extensions, but look closely at where the latch is and which corner has the square pin. If you were to measure the center-to-center distance for the pins that would be a better measurement, buying ready made cable means one less crimp tool/die to source.

    The smaller ones look very much like JST XH connectors, which you can get in male versions for crimping. and pigtails on amazon/ebay/ali. Should be 2.54mm/0.1" pin pitch if they are (some look identical but are 2.50mm pitch)

    The spade connectors look to be regular 6.3mm spade, but could be 4.8mm, measure the width of the tab to be sure.

    That said I'd just cut and re-wire? Once you're using the Duet you don't want to go back. I made a ton of adapters for my Up Mini 2 conversion, but when the warranty was no longer an issue I just cut the wires and re-terminated everything without adapters.



  • Thanks for all the input...I think you've succeeded in convincing me that making extra patch cables is overkill and not worth it. I'll focus my efforts on not burning up the new board 🙂



  • Ok, so I got as far as starting the configuration and realized I don't know much about my stepper motors.

    The only ID I have on them is a label of: SAMV008-01 and they are ~ 1.75" long. (The extruder is bigger, SAMV009-01 and ~2.375" long)

    The two main questions are:

    1. How would I know if I should enable micro stepping?
      -The Lerdge parameters listed 640 steps per mm...but no indication of whether that was after using a micro-stepping multiplier or not.
      -Is it safer to do initial setup as 640 with no micro stepping or to assume micro stepping and enter the default multiplier...and divide 640 by that multiplier for my initial value?

    2. Any idea how to setup the current limit? The default on the web confiscator is 1 amp...any reason to change that? How would I know if I got it wrong (besides smoke)?

    Thanks again, you guys are awesome!



  • Can't edit after a few minutes, so I guess I'm replying/spamming...I think I found an old post with essentially the same question and some good answers...sorry for not searching enough first:
    https://forum.duet3d.com/topic/12558/unknown-steppers/9?_=1596737462381



  • One more question (I'm most of the way wired up at this point!)

    The piezo z-probe that came with the printer only has two wires going into the Lerdge board.

    Reading through the documentation it sounds like some sort of additional board is typically needed with piezo z-probes.

    Is it safe to say that the Lerdge board was probably doing something with the signal that the Duet2 currently can't and I'll either need to get a new piezo processing board or some other type of Z-probe?

    Space is pretty tight on the end effector so my first reaction would be to stick with the removable Piezo type of probe, is that a bad idea for some reson?

    Thanks!



  • And another...

    The printer was initially wired with dual 18 gauge 24V inputs inputs from the power supply. One set of 18 guage wires went to the main board and another went to the heated bed auxiliary board.

    This seems like if I plug a single set of 18 guage wire into the duet and then run the heated bed from the duet I'll really be pushing my luck trying to run the bed and steppers from this. (the bed is 270mm diameter so ~ 280w?)

    What would the correct way to wire this be?

    Should I bundle both + 18 gauge wires into a single ferule and both -18 gauge wires into a second ferule and then plug that into the duet input?

    Or should I replace the two sets of 18 gauge from the power supply with 1 set of heavier wire? (14 gauge or so?). There's a simple place to do this at the EMI filter, on the blade style connectors.



  • @tgarr

    You would wire it the same way as it was to the Lerdge board so one set to the Duet power in +- and one set to your heater mosfet +- then the small pair of wires that went from the heater board to the Lerdge will now go from the heater board to the bed out of the Duet best to make sure you have both power pairs on separate terminals at the power supply and make sure the all are correct +- including the small pair are the correct +and- at the Duet should only go back in one way on the heater board.

    Hope this helps


Log in to reply