Is your USB cable an active cable or passive (Active meaning it can push the signal further than 6’ (more than likely 16’). I was using the one that came with my laser andit broke so I bought another one that was an 8’ and was having issue.
Is your computer power connected (outlet to the computer)?. I didn’t have mine a few times and it wouldn’t see the laser…someone said that it was because the computer needed to be grounded.
I have heard of this grounding issue. I’m not certain how the grounding works. I was (formerly) quite certain that the ground path is isolated (or decoupled from the chassis with a capacitor) when DC power is supplied. I’m curious if hanging the external power supply on a laptop or tablet adds additional noise filtering across the DC power rails… It’s a good thing that I spent money on an Oscilloscope.