Incomplete commands being sent - CNCJS or electrical interference?

Like the title says - I’m having issues with my Lowrider sometimes getting incomplete commands during a job.

I never had issues with my Lowrider before, but after letting it sit in the garage for almost a year unused, I started making improvements in hopes of using it for projects once again. I added metal parts, a macro camera, LEDs for visibility, etc. all stuff that should hopefully improve usage, reliability, and longevity of the machine. I also added a drag chain which now houses all of the cables including the Dewalt router power cable. My lowrider is using Rambo 1.4 and Dual Endstop Marlin firmware. I use CNCJS on a fanless PC to send my gcode.

I got things dialed in and it works perfect… almost. The issue I have is that sometimes - and only sometimes - during a job I will see an error in the console “unrecognized command” followed by an incomplete gcode command. It’s usually a G0 - just telling the machine where to move next, but the command will be incomplete (like missing the “G” or some part of the beginning) and so it will not be interpreted and executed. The machine then moves on the the next command and continues cutting. Depending on when this happens, there is sometimes no bad effect on the cut - but sometimes it causes the machine to not stop at the end of a line, or to change direction prematurely (ruining the workpiece). I’ve checked my gcode - there are no malformed or incomplete lines of code. The machine doesn’t get the same incomplete commands every time, and sometimes it doesn’t happen at all.

Has anyone else run into a similar problem? Could the issue be with CNCJS? or perhaps due to the underpowered PC that’s running the software? OR could it be electrical interference due to the USB cable and the router’s power cable being in the same drag chain? I want to make some sense of this before I start taking things apart. Thanks all!

I haven’t experienced that myself, but you might try separating the power and USB cables to start. Rather than pulling it all out of the chain, maybe just run a separate power extension cord separately. If that works, perhaps try a different/better USB cable between the computer and the controller. A slight improvement in shielding might make just enough of a difference.