On your 11-21-09 entry on
http://www.buildlog.net/cnc_laser/index.html you show the hookup of your power supply and mention using either 0 to 5V or PWM. I have this power supply shown in the attachment. I haven't tried running it via PWM but my first thought after reading the manual was that the PWM option needed to be requested when ordering. You get either 0-5 V or PWM. Am I misinterpreting the Chinese to English translation? Looking at it again I guess it could also mean that all supplies can do 0 to 5V (and) PWM, but you need to tell them if you want 5V or 3.3V on the PWM input?
God I wish I had a schematic for these things! They seem so simple. It makes me wonder if we couldn't do some sort of open source power supply using automotive spark plug coils. I read somewhere that the coils on a dragster produce some 30 Amps at 20kV.
All in all we really have no room to complain. I have worked with Argon Ion lasers for years and their power supplies were giant 240V water-cooled monstrosities costing thousands. Turns out they could probably also be driven by these ebay CO2 power supplies.