Y axis doesn’t drive stepper

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  • June 7, 2012 at 3:00 pm #1888
    zbird
    Member

    Hi, this is my second post. Yesterday I wasn’t able to get Y and Z working on new grblshield v2. Today,just the Y isn’t working. I’m using NEMA 17 steppers rated 3.06 V and 1.7A/phase. My PS is providing 20V and 4.3A. I can only get Z to work if X is driving at the same time. What am I doing wrong? LEDs are flashing on all axes to indicate thermal cycling and I’m able to trim pots. I can hear Y motor trying to spin. Thanks so much.

    June 7, 2012 at 9:10 pm #1889
    zbird
    Member

    Also, I’m using grbl 7d and my motor leads are blk 1A, grn 1B, red 2A, blue 2B. Sending a command like g0 x100 y100 z0 causes x to move and z to move. Any suggestions?

    June 7, 2012 at 9:51 pm #1890
    greyhound716
    Member

    zbird,

    This shouldn’t be the issue, but have you flashed to the most recent firmware? I’d recommend doing that and doing a reset of the default settings in eeprom. If you still get this odd behavior, it might be a hardware issue.

    Steps to update firmware are at http://www.synthetos.com/wiki/index.php?title=Projects:TinyG-UpdateFirmware. I don’t recall the “reset to default” command, but I think it’s on the help menu.
    -Matt

    June 7, 2012 at 10:29 pm #1891
    zbird
    Member

    Hi and thanks for replying. I loaded grbl 7d using XLoader (Windows 7) and that is supposed to be the latest firmware. I can $ receive current configs and change those settings successfully. I’ve used gcodesender and coolterm, changed wirings, etc. BTW, I’m using the grblshield not tinyg – does this make a difference? When I loaded with XLoader I had to change baud to 11900 instead of 9600 to make it flash – but now sending commands at 9600. If a hardware issue, how might I check the Arduino vs grblshield?

    June 7, 2012 at 11:03 pm #1892
    greyhound716
    Member

    Sorry, I thought you had TinyG – I missed that you were talking about grblshield. I don’t know much about that.

    June 8, 2012 at 8:21 am #1893
    alden
    Member

    Sorry to hear you are still having problems. Let’s re-examine the facts.

    – The Z axis was not working and now it is. This makes me think that the wiring might be intermittent. Have you swapped the motors around – X on Y, etc? Results?

    – All three LEDS flash when you run a command. This is good. This means the stepper drivers are working. It’s possible that Y is not putting out enough current – but it is putting out something. The LEDs do not indicate thermal cycling, they indicate that voltage is being output to the A winding. (We could have put a second LED for the B winding but in most cases this is redundant).

    – Y is trying to move but can’t. Does this happen regardless of what motor you try? This sounds like the current reference from the pot is not what it should be (assuming it’s not a motor or wiring problem). Do you have a VOM and can you read the input and output voltages on the Y current setting pot? The schematics are on the grblshield github.

    — Alden

    June 8, 2012 at 1:55 pm #1894
    zbird
    Member

    Sorry, somehow my first post never made it to this forum. Yes, I tried switching all the wired around and can drive all motors from X – all wiring good. Sending a command like g0x1000 drives X – all LEDs light up with X blinking rapidly and YZ steady.

    Sending a command g0y1000 drives Z motor – all LEDs light up with Z blinking rapidly and XY steady at first – then Y LED begins to flash slowly and motor attempts to move (is in sync with LED flashing) but hits torque (?) and returns back one step (about 1 mm back and forth). Z continues turning with its LED blinking rapidly.

    Sending a command g0z1000 causes X and Y LEDs to light steady at first, then same Y behavior begins (slow Y LED flash and step back and forth 1mm), X remains steady. Z is dark/no movement throughout.

    I’m looking for schematics to test voltage at Y but only finding TinyG for grblshield v2 (I followed link to github). Am I looking in the wrong place?

    Thanks!

    June 8, 2012 at 2:22 pm #1895
    zbird
    Member

    One more tidbit, I can drive X by itself but not Y (but do get the back and forth on spindle and slow flashing). Z does nothing but LED is steady when tested alone. So, Z only drives when X is also hooked up.

    June 11, 2012 at 2:55 pm #1896
    zbird
    Member

    So I can see the schematics for TinyG are indeed for a 3 axes and not 4 so this must be grblshield.

    In reference to ground with all three motors running, I’m getting:
    X-> 5V @ pot via and 2.4V at all pins
    Y-> 5V at pot via and 4.2, 3.0, 4.3, 3.0 at pins 1,2,3,4 respectively
    Z-> 5V @ vref via (no pot via) and 2.4V at all pins

    If I increase currency at pot on Y any higher, it shuts down.

    Thanks.

    June 12, 2012 at 9:46 pm #1897
    Riley
    Keymaster

    zbird,

    Did you change any of your settings on grbl? You can try to re-flash the board. If this does not work. Lets just get it replaced.

    Email us at… synthetos at gmail.com and we can go from there.

    Ril3y

    June 13, 2012 at 11:15 am #1898
    zbird
    Member

    Yes, I changed my grbl settings and re-flashed. I’m going to switch out the Uno today (brand new) and if that doesn’t work, I will email you. Thank you very much.

    September 11, 2012 at 6:09 am #3470
    dizymac
    Member

    Hi,

    I’m also having similar issues on the y axis stepper driver. I have an Arduino Uno also plugged in with grbl 0.8 successfully running on it. Both my x and z axis stepper drivers work perfectly, but the y doesn’t light up or move the stepper when I send commands to it. The other 2 axis’ lights do however.

    The y axis light does light up when you manually physically move the y axis gantry position, I’m not sure if this means it is okay or not?

    I have eliminated the possibility that it is the Nema17 stepper motor at fault, by swapping over the y axis motor to the other axis.

    I have also reflashed grbl several times to determine this isn’t the issue. I’ve used a little jeweller’s screw driver that isn’t capable of forcing much torque to change the position of the y axis’ variable resistor or capacitor, this is still within 270 degrees.

    Please help, I’m out of troubleshooting ideas?

    Thanks,

    David

    September 11, 2012 at 6:42 am #3471
    alden
    Member

    David,

    You have done all the things to diagnose this. It sounds like the Y axis drive is not working. One question – is the Y current setting pot OK? If these pots get over torqued (moved beyond their 270 degree rotation) they fail.

    In either case it sounds like a board replacement is in order. Please contact us at the synthetos email address to arrange.

    – Alden

    October 22, 2012 at 8:42 am #3571
    julian
    Member

    Hey guys i been having some trouble with the X axis.

    When i start a job it may work the first 20 steps (if i’m lucky).

    The pot only works between 15 – 16 hours. i can’t over torque more than that, if i do it doesn’t move at all. and it doesn’t move as smooth as the other axis.

    I Checked the windings and the motors, i got the shapeoko bundlle.

    – Julian.

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