I was using my laser yesterday. It wouldn’t complete the job I sent to it, so I moved on to a different project. I began the new project and before anything cut, it ran into the side of the machine (although I checked the cut preview and it should not have been a problem). After that, I have been unable to establish a connection to the machine (whether I run it through a dumb hub or a usb a to usb c adapter). The console says “Waiting for connection…”. The program lists the ports it’s on, so the computer recognizes the device. I was running the most recent release and found that the problem could be the version. I downloaded a pre-release version and backed down to 2.0.02. That didn’t work-- not surprising since it was working using the new release. I redownloaded the CH341 driver. I tried a usb-a to usb-c cable; naturally that didn’t work. Is my best bet a new usb-a to usb-a cable or something else? Thank you for your time and ideas.
Machine: OmTech K40+ (grbl, I believe)
Computer: MacBook Pro running Sequoia 15.6.1 (24G90)
Firmware: ?
USB cable (connections) are often the culprit for communication problems between the laser machine and the computer, especially if the maximum length for USB is not respected.
However, I read your MacOS version number and would recommend looking for version 15.7.2. It has helped a lot with performance problems I have had on my Macbook. It could be that it also helps with the problems you are struggling with.
I have updated Mac OS to 15.7.2 and replaced my usb cable. No luck with that I finally just deleted the device and created it again from scratch. At least computer and engraver are speaking again!
The trick to getting the connection, finally, was removing the device from LightBurn and manually adding it back again. Now, however, the laser will not fire when I start the job from light burn. The laser will fire with the machine’s test button. The readout on the top of the machine says the laser is getting the signal, but there is no power output in mA on the readout. It also will not manually test fire the laser from LightBurn. Now, I do not know if it is a setting issue or a different issue.
It does, in fact, mean something. I guess I didn’t have enough water flow through the laser tube. Reversed the flow briefly, set it up correctly, and now it is working.
Sometimes the solution is so easy, great that you figured it out. Btw. water protection alarm is the most important and best safety device on CO2 laser, it has saved many (me included) from investing in new tubes too early.
I finally just deleted the device and created it again from scratch. At least computer and engraver are speaking again! 
