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TinyG Motors 2 and 4 not working

From the original Synthetos forum (2011–2025)

Started by Doigberg on in TinyG Support. 5 replies, last activity Dec 13, 2018.

Doigberg #

Hello,

I am having trouble with my TinyG V8. My motors 2 and 4 are not working.

My problem:

- My TinyG worked fine for about 1 month until motors 2 and 4 stopped working

- My settings are: 1ma=0, 2ma=1, 3ma=2 and 4ma =1 (the Y-axis is cloned on motor 4).

- The green lights flash when I jog the motors 2 and 4 but there is no movement (the steppers don’t even make any type of movement or hum whatsoever)

- The stepper motors themselves all work because they work when I plug them into motors 1 and 3

- It doesn't matter which steppers I connect to motor 2 or 4, none of them work. I can map motor 2 or 4 to the X, Y, or Z axis and it also does not matter. None work.

- I have tried adjusting the trim pots to maximum on motors 2 and 4 but this does not solve the problem

- I have reset the board to its factory default many times using $defa=1 but to no avail. I have also pressed the reset button on the TinyG itself.

- I am working in a default TinyG environment and have not many any changes.

- I am connecting through the JSON server and using the online browser to power the board (Chilipeppr)

- I have updated the firmware to the lastest version

- The exact same problem occurs on Universal Gcode Sender too

- I use the same USB cord and 24V Meanwell power source on my xproV3 on my other CNC machine with no problems so I don’t think they are the problem.

- This is the weirdest part: When all 4 stepper motors are plugged in, (1ma=0 2ma=1 3ma=2 4ma=1), and I try to jog the Y axis (which should activate 2ma and 4ma), instead, the 1ma (z axis) will hum but not move. Basically, this means that the Z axis (motor 1) is being activated when I try to jog the Y axis (motors 2 and 4).

Please help! I’ve been banging my head on this problem for days – and it’s super frustrating. Thanks!

cmcgrath5035Staff #

First, the easy one

– This is the weirdest part: When all 4 stepper motors are plugged in, (1ma=0 2ma=1 3ma=2 4ma=1), and I try to jog the Y axis (which should activate 2ma and 4ma), instead, the 1ma (z axis) will hum but not move. Basically, this means that the Z axis (motor 1) is being activated when I try to jog the Y axis (motors 2 and 4).

What you describe is normal behavior if you have $_pm=2 setting. (_=1,2,3,4)
Usually, $_pm=2 is preferred. When ANY motor is moving, all static motors are energized to hold thei current position.

Two(of many) possibilities for your bigger issue
PWB/mechanical: If you have a multimeter, follow the trace from each output screw block back to it's respective output pin on the 8825 drier device.
Then measure the resistance from the device lead to the connector screw head. It could be an issue with the connector body.
While you are at it, double check the connections closest to the steppers, most installations have 4 wire 18ga or so cables between tinyG and the steppers, with connectors/splices near the steppers to the 24ga (or so) leads into the steppers. It is easy to bork the connections.

Settings: Grab a parameter dump from a console ($$ command) and post it to a cloud drive (gDrive, etc.) and provide a URL. That will save us several iterations of "what is $blah)

Doigberg #

Thanks so much for your response,

Please see below for my dropbox link with the parameter dump from the console:

https://www.dropbox.com/sh/etvceuj6qvqxv7f/AACx0bkTMKdAcRScVvGDCQ1ba?dl=0

Two(of many) possibilities for your bigger issue
PWB/mechanical: If you have a multimeter, follow the trace from each output screw block back to it’s respective output pin on the 8825 drier device.
Then measure the resistance from the device lead to the connector screw head. It could be an issue with the connector body.
While you are at it, double check the connections closest to the steppers, most installations have 4 wire 18ga or so cables between tinyG and the steppers, with connectors/splices near the steppers to the 24ga (or so) leads into the steppers. It is easy to bork the connections.

My apologies, I'm new to CNC/controller boards. I'm not quite sure where each of the items you mentioned are (ex: output screw block) located on the TinyG. To aid in our discussion, I have taken a picture of the TinyG (and included it in the Dropbox link) and have written the individual items that I am supposed to locate in colored font. May I ask that you use MS paint or other software to point an arrow to indicate the location of the items on the TinyG? Alternatively, I am more than happy to send the board back to Synthetos and pay a fee so they may diagnose it on my behalf.

Thanks

cmcgrath5035Staff #

Lets start here:
The wiki, particularly https://github.com/synthetos/TinyG/wiki/Connecting-TinyG, should help you navigate what pin is what.

Since you say it worked for a month, I suspect that you did not re-enter your parameter set after executing $defa=1, because the current parameter dump is incorrect for a machine wired as X,Y,Z,Y , or as you describe

– My settings are: 1ma=0, 2ma=1, 3ma=2 and 4ma =1 (the Y-axis is cloned on motor 4).

You likely had a different parameter set in the first month, when the machine "worked".

The immediate tell-tale is that $2tr=40mm but $4tr=2.116mm, both are driving Y motors so need to be identical.

The "factory default" parameter set, installed by the $defa=1 command, is not likely to be correct for any particular machine.

The parameter set you posted look like a generic Shapeoko setup for an X,Y,Y,Z machine.

What machine do you have?
A custom build?
Buy from someone who set it up previously?

Spend time with the wiki, particularly the Connecting and then the Configuring sections.
That should get you back to a point where you can jog in X, then Y, then Z spaces.
Add a picture of your machine connected to the tinyG to your dropbox, and keep the parameter dump up-to-date when you come back.
The parameter dump answers a lot of questionsI might have

Doigberg #

Thanks for your reply.

I have a Cbeam machine from Openbuilds. There have been no customization to the machine so it is not a custom build.

I have read the connecting and configuring sections but still am at a loss for what to do really. Even when I try to move the Y-axis by itself (and not have a dual Y axis setup), the lone Y axis does not work (when attached to motor 2). I have stripped the motors from my cbeams machine and am just working with the motors by themselves. Motors 1 and 3 work flawlessly, but I'm still having trouble getting any movement from motors 2 and 4 at all.

cmcgrath5035Staff #

From my end, I don't know how you have implemented "..(and not have a dual Y axis setup),....".
Did you change parameters?
Did you physically disconnect Motor 4?

Using the parameters you posted on Dropbox above, try this:
From a command console, send $4tr=40.0 command and see the response from tinyG.
Reset tinyG (hit the reset button), run $$ again.

Verify that you see $2tr = 40.0 and $4tr = 40.0.
Now see if you can jog the Y axis motors.

The problem with the Dropbox parameter set is that you have two different definitions for movement of the Y axis, 40mm per revolution and 2.1166 per revolution. When tinyG tries to make calculations for Y movement, it does not know which one to use.

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