Still Getting disconnects!

Hope you allow “others” to comment, meaning I recently received my new Longmill MK2, and I (and some others) are having the same issue: Random disconnects and stops. I’ve also been troubleshooting for a while, with much of what you’ve done plus installing a replacement Arduino Scienci sent me. I, too, have performed numerous “dry runs”, or air cuts, with nothing running but the gcode, issue remains. I’ll go one step further: I’ve been connected, to jog the machine, then went about my business on the table and it will disconnect while 100% idle. As you have done, I’m sure I’ve addressed all the power management settings on my Windows PC’s, I’ve tried a newer HP Win 11 laptop and an HP Win 10 LT, where I set pwr management to never sleep and made sure the USB controller settings were set to not allow the computer to put it to sleep. I’ve also ran them on battery and plugged in. Just adding to the conversation to let you know it’s cross-platform. Also, I use a DeWalt 611. If we come up with anything “on the other side” I will certainly share with your group.


I was having a similar problem and it was exacerbated when I switched to laser. Here are a few things I did which all but eliminated unexpected disconnects: this was even more problematic when running light burn.

  1. I have a small tablet running windows as the controller for the shapeoko. Besides disabling sleep I also when into the serial port (under the port settings for shapeoko in device manager) to establish hardware flow control

  2. Lowered the baud rate to 115200 on sending for lightburn

I’m new to the thread and it must be frustrating to have these disconnects.

My company does a lot of work in the audio field and grounding issues often lie at the heart of problems we encounter. Even very subtle differentials between ground level voltages (and currents) can make ultra-low current chips to become unstable. Any current flow from one ground area to another is a source of problem. A ground needs to have zero differential.

In audio, this can show up as hum. However, in today’s chip age, ground differentials show up way before hum. Chips will tune out because their ground point “floats” relative to another and the signal they are reading fails. In high frequency (GHz) systems, even differences of a few inches between two parallel leads can cause radio frequency interference.

The solution is star grounding the system. Star grounding means that everything is closely connected to one central point. Even small differences are eliminated. Any daisy-chaining is eliminated.

Not knowing your setup you may have already done all this. My main thought is that the differentials we encounter can be easily overlooked because they seem to be trivial.

Hope this helps.


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Have had the same issue for over a year. C3D was kind enough to send me a shielding package that helped slightly but had no real solution. Went thru all the Q and A, the problem still exists. On a good note, C3D really bent over backward to help.

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Thought I had a solution but had two disconnects today. Both over couple hours into the job. 4 hour job has taken over six now and counting. Disconnected bitzero. We’ll see. Frustrated to a bad point as of now.

I’m not sure if this did the trick or not, but I tied all grounds together multiple times and then powered the vacuum from separate circuit. But ground still tied together

When running your grounds you want to have a single ground point, a star ground topology. Grounds connected together multiple times make a Wheatstone bridge and the real possibility of making the noise problems worse by creating ground loops. In my system I have a PE (Earth Ground) bus bar and all of the ground wires and shields terminate there. Except when I experimented with a section of clear vacuum tube I have not had any disconnect issues.



Seems that the problem with the disconnects was the bit Zero. As soon as I physically unplugged it the machine ran a job with no disconnects. I reached out to Carbide and they had me send it back, they fixed it and sent it to me within a week.
Customer service was very patient and asked me all kinds of questions. I’m still going to keep the recommended hardware and upgrades on and let it work!
Rich did come over and took a look and it worked for him as well!
Thank you all for your input it was very much appreciated!



Any idea what was wrong or what they fixed?

Glad you’re up and running!

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I wondered if you tried running the machine without any dust collection. It might help narrow down the source of the problem. Also maybe give the work area and the dust hoses a shot of anti static spray.

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