To check PWM you really need a scope. A multimeter checks voltage/current/ohms. You really can’t measure it realistically on a multimeter.
If you have a miliamp meter, it’s reading is relative to output power. It is connected to the low side (going to ground or return) of the laser high voltage supply line.
If you have a meter such as this one on my machine. It’s next to the emergency off button on my machine. My power supply also has a digital ma meter. It is relative power, but is the current flow through your tube. Shorter PW, lower current. I try not to run mine over about 21 ma. Most of the engraving is about 4 ma. You cannot judge the output from the power input, generally speaking.
Good question… I’ll have to look at mine…
Could you have possibly crossed up LPWM1 and L-On1? That would cause this I believe.
Here are the connections to the laser power supply. At least in my machine.
From what I can see the only control lines go to L and IN. From the Ruida CN5, L-On1 goes to the L pin of the laser supply. LPW1 goes to the IN of the supply.
It looks to me that the L-On1 enables the laser and the IN line is the PWM input.
Double check those…