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Z switch broken on UM2


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Posted · Z switch broken on UM2

I decided to build a UM2 clone and not surprisingly I am running into problems.

 

Got it assembled and installed the marlin firmware. Using Cura 2.4 and "Automatically upgrade Firmware"

 

When going through the first start up after the last window after you push the button for the last 

time I get "Z switch broken" and nothing else happens from there.

 

I have metered out the mother bd and am confident it is not a physical switch or mb problem.

The mother bd is a 2.1.4.

 

Anyone have any ideas/solutions?

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    Posted · Z switch broken on UM2

    Hi Spenter,

     

    Since this is the first startup of your system, there is a few thing to check..

     

    First, did you install the two safety links?  Those two link can be used to cutoff the 24VDC to all heaters and stepper motors. so if this one is missing, you would not have power to the stepper motors to move.

    During the setup the Z stepper will move toward the z-stop in order to synchronize. If this voltage is not present, no movement of the bed toward the stop, so after a timeout the Z-switch fail is flagged and it will display; "Z switch broken". 

     

    When turning on the power switch for the printer, you should be able to hear a solid click when the relay is activating.

    To verify that this voltage is present, do as follows:

    Also the 24 VDC "switch" the (only one) relay K1 might be faulty, check the TP21 (Test Point) for 24 VDC on the underside of the PCB.  You will find the test point close to the heater connector.

     

    I'll assume you know how to do this procedure.

     

     

    Lets do this check as a start.

     

    Good luck

     

    Thanks

     

    Torgeir

     

     

     

     

     

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    Posted · Z switch broken on UM2

    Torgeir:

     

    Thanks for your reply.

     

    Both jumpers for the safety's are present.

     

    I am getting

     

    23.9V at tp21

    3.2V at tp16

    4.8v at tp16

    1.1V at the resistors in the schematic at tp405,433,418.

     

    None of the axis move. Even the Z when it says to turn the knob

    to move the bed close to the printhead.

     

    Should have occurred to me that could cause the error I am getting.

     

    Dan 

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    Posted · Z switch broken on UM2

    Hi Dan,

     

    Voltages Ok., so lets check the wiring to the stepper motors.

    The pin 1 and pin 2 should have one of the steppers coil, -so pin 3 and 4 the other coil. You'll measure approx 2.0 ohm res.

    Different steppers might differ slightly.

    If there's was other fails another error might be seen, so after this part it is the servos to move and sync. Next after this we might have a look on the firmware you have.

     

    Torgeir

     

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    Posted · Z switch broken on UM2

    Torgeir:

     

    It is sort of working now. I had to switch a couple wires on all the motors.

    Now on to the next adventure. Tight x axis and the motor does not move just

    makes a lot of noise but I am sure that is due to alignment of the frame.

     

    Thanks so much for your help I would have spent hours to figure it out if at all.

     

    Dan

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    Posted · Z switch broken on UM2

    Torgeir:

     

    Thanks for your help. My problem was due to wires being switched

    on the cables to the motor. Switched the center two and now on to my

    next adventure.

     

    Could not have done it with out your help.

     

    Dan

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    Posted (edited) · Z switch broken on UM2

    Hi Dan,

     

    Great findings, enjoy the printing in 3D world.

     

    If it have problem to move, just check the current the motor is set to, should be about 1200 mA..

     

    Regards

     

    Torgeir.

    Edited by Torgeir
    Edit.
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