Converting control board from old diode to CO2 psu

[horhe_]

hi friends! I have a diode laser, I would like to upgrade it to CO2 keeping the frame, motors and the control board, the control board controls my diode laser by PWM signal in a range of 0-3.3v (0v - 0% power / 3.3v - 100% power), I was able to convert the power output from the board to 5v by level shifter, so it turns to 0v - 0% power, 5v - 100% power, I also tried some opto coupler and was able to get 5v at 0% power and 3v at 100% power, I didn't try to fire the CO2 psu yet by this board since I'm unsure how to make it the right way, I should be thankful for any advises on how to try to connect and control the CO2 lps by my old board from diode. I have attached photos of the board + lps. Many thanks!