Duet Maestro expander drive 5 overheating



  • So I bought the new expander for the Duet Maestro. I installed it and mapped 2 Z drives to it (5+6) for tripple Z leveling (with drive 2). I used to run 2 Z steppers for leveling on drive 2 and 4. I moved the stepper that was on drive 4 to drive 6 and added another stepper to drive 5.

    Everything tested and leveling worked like a charm, time for a test print....

    however without changing the current to the steppers from before (they are at 1000mA), drive 5 is telling me its overheating after a couple of minutes printing.

    Can the expander module not handle 1000mA like the ones on the PCB of the Maestro?

    Could this be perhaps because of the mounting hole, thus making the copper heat transfer smaller maybe?

    I did not receive any cooling heatsinks with the module nor a mounting post for the mounting hole from an official reseller, is this correct?

    My Maestro is mounted verticaly for heat dissipation already. I have been running it a couple of months this way. Expander module is just plugged in the expansion header (but without a post).



  • post your config.



  • Without bloating this post too much, heres the important stuff regarding the Z drives:

    M584 X0 Y1 Z2:5:6 E3 ; mapping drives, X on drive 0, Y on drive 1, Z on drive 2,5,6, Extruder on drive 3 (E0)
    M671 X-39:257:257 Y110:57:160 S8 ; Z leadscrews are at (-74,110),(257,57),(257,160), max compensation is 8mm
    M906 X1000.00 Y1000.00 Z1000.00 E600.00 I30 ; Set motor currents (mA) and motor idle factor in per cent

    If more is need, I could post it all... but I dunno if that is relevant?



  • are they in that order in the config as well?



  • yes they are.

    I think I found the culprit maybe... The stepper that is on drive 5, is an old Anet A8 stepper. When searchring for specs for that stepper, I see that they are only rated 900mA... Could that be the reason? I would however think the stepper would be getting hot instead of the expansion module?

    Anyway, I set it to 800mA and did not receive an overheat warning now since a couple minutes.

    Can I check what temp the drive is currently?



  • not from the driver itself. it only has hot and overheating as information.


  • administrators

    @mmmark84 said in Duet Maestro expander drive 5 overheating:

    Anyway, I set it to 800mA and did not receive an overheat warning now since a couple minutes.

    How is the board and the expansion mounted as far as airflow is concerned? The drivers are capable of 1.4A with good cooling (blowing a fan sideways across the board). Another thing to try is if you are not using driver 6 swap to that and see if you get a different result.

    @mmmark84 said in Duet Maestro expander drive 5 overheating:

    I did not receive any cooling heatsinks with the module nor a mounting post for the mounting hole from an official reseller, is this correct?

    The drivers are cooled through the PCB so normally heat sinks are not required.



  • @t3p3tony I mounted the board virticaly with standoffs of about 5 mm onto a piece of multiplex wood and its not built into an enclosure so around 5 cm around the PCB are cable mount trays. The electronics of the printer are at the backside, not enclosed from air. So it gets ambiant room temperature as cooling. No fan is mounted.

    I have also another printer with duet wifi and duex 5 running, also same mounting mechanism and even running 1200mA on all steppers. I have been running that printer without ever receiving this warning for over 1 year now with almost daily use.

    I know the drives are cooled through pcb copper, but the copper surface area at drive 5 is severly smaller because of the hole for a standoff. That made me think its not getting proper cooling.

    I can try swapping 5 and 6 to see if that changes it from 5 to 6 (with setting back to 1000mA) but my printer is now 100% occupied for the next couple of days.

    For now I also added small 4988 heatsinks to the ICs of drive 5 and 6 and running 800mA for around 6 hours now, maybe I will leave it like this.


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