Crackling noise coming from laser power


My cutter (a 7040 from China, Ruida controller) has just started making a crackling/arcing noise in the middle of a cut. It sounded like welding - sparks cracking, but quietly. Only occurs when the laser is on.

Does anyone know what this could indicate? I won’t have time to investigate for a week or so but any early heads-up would be appreciated.

edit: I’ve quickly checked the tube and all seems intact. The electronics hatch looks fine and smells sparky, but the cutter will need totally moving in order to make the hatch accessible so I can’t do a full look.


Firstly a warning. There might be large amounts of static or discharge sitting about in your machine waiting for you to touch the wrong thing. If the machine is arching somewhere it’s also possible you’ll get a shock just touching the machine. Ensure your machine is properly earthed also.

It’s possible that there isn’t enough insulation around the anode/positive connection on your tube or that there is a place along that connector where the wire is exposed, though this would seem unlikely.

Another possibility is that your cathode/negative wire (at the blinding/shooty end of your tube) is not connected at all, either at the tube end or on the PSU and is arching to the case of the machine.

Yet another possibility is that your PSU is just horribly cheap and that’s the noise it makes when it is working. It might be worth noting the type of PSU you have and being prepared to replace it. If you have the laser cutter I think you have, the PSU is situated in the side bay at the back on the right, directly below the anode/positive end of your CO2 laser tube.

Let us know how you get on.