I received my pre-owned CO2 laser engravers yesterday. A pair with mixed prospects. These are typical of the cheaper Chinese units with no interlocks, external water pumps without flow sensors and a cryptic controller board.
The smaller one with a 20×24 cm working area, a 30W tube and vintage Parallel port controller interface, no software. The Z height is controlled by a surprisingly crude scissor jack that could never have worked well. It has a side feed air assist and a digital tube current display. This unit has worked hard but the controller homed the lens on power up and tapping the test button burnt a hole in a sheet of paper with the unfocussed beam.
The second unit is larger with 40 x 50 cm working area, has a fixed T-slot bed with no Z height control and missing the tube, slightly newer controller with USB interface, also no software. This unit seems to have done very little work and is clean.
These units are destined to be put to work and will likely receive the LaOS brain transplants unless I find suitable software that does not require a dongle. I have spare PSU boards so should be able to get the other unit working as well. The power supplies are only rated at 30W but the larger unit might fit a 40W or 45W tube in the case, so I might get it a bigger tube for it if I can find a slightly bigger power supply that will suit.