My Duet can be reused / avoid the same issue

  • Hi,

    Open this new post, the other think its closed..

    after discover why dont works motors in my printer....

    Motors dont works

    I have thinking 2 ideas:

    A) Avoid this issue in new Duet.

    I dont like, in new board, that drivers burn, and i want comment ideas i haved, and if you have more, please tell me:

    • Using lower current in config,g. The driver burned, seem E0, that correspond to extruder, that its the stepper with a low current in config.g
    - M906 X1200 Y1200 Z1200 E800 I40 ; Set motor currents (mA) and motor idle factor in per cent

    How its minimun current i can use? maybe M906 X1000 Y1000 Z1000 E500 I40, or its too low?

    A1- Mount a passive heat sink for chips... something like this Heat sink
    A2- Blow a fan over drivers. Currently, the fan where the Duet plate is housed, in the printer, the original location in the Tevo Little Monster (120 mm), there is installed a fan, connected to always on, which cools the entire plate .... It would be or relocate this fan on top of the drivers, or mount additional fans on top of the drivers connected to socket 2, always on.

    B) Try to recicle burned Duet, for this i see two options.

    B1- Mount a DUET 5X, i need 4 drivers.
    B2- Mount drivers. I think i have some Pololus. Using external drivers

    • I like more, use a Duet 5X, seems more clean, but i dont know, if the burning drivers, can affect if i mount a DUET 5X. How can check if DUET 5X will work in burned DUET. I have see this in Wiki Duet 5x wiki info. Is there any way to check if Duet 5x, will work on my Duet 2 (rev 1.3), with the drivers burned?

    I add photos for remember issue. BURNED E0?

    1_1547703024638_Duet 2 1_3 Photo Sttepers B.jpg 0_1547703024638_Duet 2 1_3 Photo Sttepers A.jpg

  • You can have the bad driver chip replaced on that board. Not sure where you are located but there are people that can do the repair work.

  • If you're sure that it's only the driver chips, they can be replaced, and it's probably cheaper than buying a Duex5. Are all of the driver chips fried, or just the E0 one? If it's just the E0 one, you might be able to just re-map the extruder to just the other driver.

    If you've fried all of them, it seems unlikely that it would be the driver current at 1200mA, since that's well within the Duet's capability. that looks more like something that happens with a short circuit

    The default current from the RRF configurator is 800mA, which is probably enough for most motors. What's enough or too much depends on the motors that you're using. Some motors are good with lower current, and some need more.

  • administrators

    Burned drivers are rare now. There a time nearly 2 years ago when too many drivers were popping, but we changed our testing to test them at a higher voltage in order to weed out weak ones, and after we complained to Trinamic about the failure rate we think they improved their QA too.

    The things I know of that do burn out drivers are:

    1. Shorting two of the 4 output wires to each other, or shorting one of them to ground or VIN;
    2. Connecting the motor to the driver incorrectly. It's important to connect the two wires belonging to one phase of the motor to the two pins at one end of the 4-pin connector on the Duet, and the 2 wires belonging to the other phase to the 2 pins at the other end. If you get it wrong then this leads to high currents, which may cause failure of the driver.
    3. Using excessive VIN voltage is also likely to damage drivers, so the VIN voltage should not exceed 25V. This allows a margin of safety, because it's not until you get above 28V that damage is likely.
    4. A classic way to damage stepper drivers is to disconnect the motors while they are powered. Although in my tests on the Duet, in the TMC2660 drivers survived this repeatedly - see the video I posted.

    [Edited - added item #4]

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