Can't go below 30%

Put in a new controller (RDC6445G) and can’t go below 30% I see to trying to flash but if I I put apiece of paper in front of it I get no mark on it. I have 2 90w co2 lasers

thank you for the help

The old controller use potentiometers to control the power.

“I see to trying to flash” - I have no idea what you mean by this.

Laser tubes have a minimum power required to make them fire, and larger tubes have a higher firing power required. 30% is pretty high - I’d expect between 10% and 15% with your machine - but if the power supply hasn’t been tuned to the tube it’s not impossible.

I can see the tube fire but is very faint below 30%. If I put something in front of the tube like a piece of paper it leaves no Mark below 30%. The tube is a Yongli A2s and this is the data plate off power supply

You need to know the mA output at 30, 40, 50, 60% etc. If at 90% for example, you’re only outputting 20 or less mA, your power supply is not adjusted correctly.


Since you said this started only after you installed a new controller, then make sur eyou check the controller’s manufacturer setttings for min and max output. Set this min to 10% (usually the floor for a 90 / 100w tube) and set max to 100%. Then adjust the Power Supply trim pot so that 100% PWM to the laser PSU isn’t over or under driving the tube.

Some shots of my controller settings if this helps you at all (having the same controller and HMI):

Thanks for all the help. At 90% I was getting 30mA.

Who makes your CO2 tube? Does it have rating sticker?

30mA sounds too high to me.
Most tubes need to be mid to high 20’s


All my settings look the same. I have a new power supply that I can try . On the controller I have the laser on L-AN not LPWM. The old controller had potentiometers to control the power and not pulse-width modulation. I’m pretty sure it is a setting that I’m overlooking in the controller but I’m not too sure.

Yongli A2s is the tube

What is it rated up to?


I’m curious what that Laser Signal Level is for. I was wondering this earlier today. Is this something to accommodate different tube manufacturers? Does a Yongli tube prefer a high signal level? What does signal level even mean?

The tube is a 90w.

I think it’s the trigger signal High or low?

This is my laser settings

I tried a different power supply and hooked it up the way this schematic shows but I cannot get it to fire. If I disconnect the controller and push the fire button on the power supply itself it will fire but if I have the controller hooked up and push the test button power power supply it will not fire.

It is possible that you have a defective controller. Did this controller ever work? How old is it?


It’s two months old. We engrave silicone. If the power is to high it will go through the silicon.

This is what we are trying to do. Right now it’s engraving too deep on this machine.