The Big, Bad M4 Troubleshooting Problems/Solutions Thread

Note: This topic is for collecting problems and solutions so they can be documented in the wiki. It is not for asking questions about your problem. If you are having a problem, go to the Troubleshooting Category and start a new topic!

If you had a problem (with assembly, frame design and construction, calibration, operation or something else) that was documented in the forums, please post a link to the topic here. Ideally, the topic includes a solution to the problem, but I’m not afraid to have an “Unsolved Issues” section in the Troubleshooting section to let people know what we don’t know.

If you know of a problem that you saw in the forums but you can’t find it, you can post a description here and hopefully someone else will be able to find and link it. If you have or know of a problem that hasn’t been discussed, I suggest you start a topic about that problem so the community can weigh in on it before we try to document it.

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Thanks, everyone for your help in smoothing the way for future users!


Things that can cause calibration problems.

If you are having problems calibrating, it can be useful to take a video of the
process and post that video

  • incorrect horizontal/vertical setting (aka “my sled fell on the floor”)

    • vertical is where the sled is hanging from the belts and will fall to the
      floor if the belts extend
  • problems with belt movement

    • failure to properly retract/extend/snug up the belts. The maslow does not
      know the belt position when it powers up, it need to retract all the belts until
      they can’t retract any longer to find the ‘zero’ position. If the belts catch on
      something or otherwise are prevented from fully retracting, all further
      operations will be wrong. (there is work being done to save the position across
      power on, but that has it’s own problems)
    • If the belts do not reliably extend/retract to the same value, calibration
      will not work. When you do a retract-all, the system reports what the belt
      length was when it got hard enough to pull the belt that it gave up. If these
      values are not near zero after you extend/retract the belts, track this down
      before anything else
      • if the belts are not retracting fully, one thing you can do is to increase
        the current limit at which the system decided that they are fully retracted. If
        you do this, you also need to set the calibration current limit to the new
      • adjusting the motor position or extending/retracting the belt a few times
        can make it move better
      • if belt movement is very uneven, check the magnets. If the magnets are in
        the wrong ‘gear’ or can slip in the ‘gear’ it can result in inconsistant
    • If the belt catches on something while retracting to take a measurement,
      that measurement will be incorrect and even a few bad measurements can
      significantly throw off the calibration.
  • problems with frame/calibration size settings

    • the current calibration process works better if the initial frame size
      provided in near to correct, and it helps if the frame is very near square
      (measurements of the diagonal match), but it will work if the frame is not
      square or even close to a rectangle. If you get errors about being unable to
      move, try setting a slightly larger frame dimension.
    • If you set the calibration size too large, you can fall off of your
      workpiece, try again with a smaller calibration size.
    • workpiece too large for the frame. If two arms of the maslow hit the pastic
      frame trying to go in different directions, the system cannot detect this and
      the actual distance to the anchor will be shorter than the system thinks it is
      when it pulls the belts tight. The jury is still out on how badly this affects
      accuracy when cutting, but it will throw off calibration.
  • Z errors

    • The maslow instructs you to run the Z axis all the way down to have the
      frame against the stepper motors before you run calibration. If you do not do
      this, the Z distance between each of the belt arms and the anchors will be
      incorrect. This will result in the actual distance to the anchor being less than
      the system thinks it is.
    • If you have a non-standard router, you may need to
      alter the Maslow_**Z values in the maslow.yaml file (add link here to how to do
      it via settings)
    • If you have an unusually thick spoilboard/workpiece under the sled it will
      make the default values (which assume 3/4 plywood spoilboard and nothing else)
    • If you stack the arms in a non-standard order, the default Z values will be
  • frame flex If the anchors move as the belts tighten, this will cause errors as
    the belts will be pulling in different directions at different strengths
    depending on where the sled is on the workpiece. (this is one of the things
    easier to see in a video than live in many cases)

David Lang


Software issues:

Calibration takes place both on the device and in the web browser. During calibration it is important to have your web browser active for the whole session. Make sure you don’t disconnect and only access the maslow during calibration from one device. If you have multiple web browsers then they can both respond to the calibration events, causing issues.

Capture the serial messages after calibration (success or failure!) by selecting the text inside the log under all the maslow buttons and copying it into a file or email. This can be very useful in the forums if asking for help on calibration issues.


What is calibration

Calibration is figuring out exactly where all the anchors are.

It should only need to be done once and is saved in the maslow.yaml file. If you
lose the maslow.yaml file (including overwriting it without saving the maslow_*
values), or change your frame size, you will need to do it again.

The maslow from dimension is defined as the lower left anchor being at (0,0) and
the lower right being at (Maslow_brX,0)

The Maslow has a built in process that figures out the locations of the anchors
by taking multiple measurements of the belt lengths.


Here’s the punchline of the topic on the Error:82 issue: Having trouble after calibration - #44 by Gijs


Not resolved yet, but I want it on the list: Push to extend bug?


To recover from ALARM trigger due to panic with message no heartbeat detected -


“What does error code: x mean?”

FluidNC error codes (may or may not help :slight_smile: )
Alarm and Error Codes | Wiki.js


Regarding Apply Tension button:

I’ve noticed it can be a good idea to do it again before cutting if you’ve been jogging around and a belt goes slightly slack.

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When updating firmware after you already achieved sucessful calibration, what variables do you need to copy over/update in your new yaml file that you also just copied over for the new firmware:


I’m not sure if that information is best put in the troubleshooting section–I’m open to opinions about this–but in any event that is absolutely great information for the wiki.

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Yea I am new to these types of forums/projects my bad. what/where is the wiki?

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Not at all. I was just trying to start a conversation about where the best place for that information is. But since you ask, here’s the wiki for the Maslow 4

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Thanks! I didn’t see that Wiki before–super helpful! Cheers

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TL;DR: A heat sink that shorted contacts on one of the connectors.

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