Cant get laser to fire


I’ve just purchased a year old 60w chinese laser with a 644xs ruida controller but can’t get the laser to fire and was hoping someone can help me. I have a lot of experience with lightburn and a g-code controller but can’t figure this one out. When I send a file to cut or fill, it moves as if its trying to execute but the laser is not firing. If I manually fire from the laser power supply when the laser is stationary it does nothing but if I move the laser and manually fire it will fire proving that the tube is ok.
Any help would be greatly appreciated.

Is it the test button on the PSU itself you are referring to or the Ruida panel’s fire button?
Is there an ammeter on the machine?

Its the test button on the PSU itself and there is no ammeter on the machine.

It’s not that good, you do not know where you are in the woods.
Has the machine been running at any time while you have had the machine?
Hopefully only some settings in machine settings are wrong. In LightBurn, everything is as it should be, you say, also min.power / speed?

Today is my first time trying to fire it up. I did see it operating with the person I bought it off. It could be settings as I have only just installed the latest version of lightburn for the DSP controller.

The laser should fire not matter what the rest of the machine is doing if it’s the test button on the lps. The test button overrides everything else generally speaking.

If you have protections setup for water flow that goes directly to the lps, then it’s possible that could prevent it from firing. I’ve never tried that…

If what you mean, is you have to run a job to test fire it, it’s probably the Ruida allowing L-ON1 (-> ’ L’ on the lps) to go high disabling the laser when there is no job running.

Is there any error messages in the window at any time…?


There are no errors when I try to run a job file. If I hold the test button on the LPS while the file is running, the laser will fire but I get nothing when I try to burn or cut under normal running conditions

Is your cover protection activated? and is the laser on ?, this switch does not give an error message if it is not on, it may also be defective.

This seems to indicate that there is a problem with the PWM control from the Ruida.

Do you have any kind of test equipment?

A complete electronics lab is great, but you can do with a voltmeter.

The output of the Ruida for tube one is LPWM1 and that generally goes to the ‘IN’ on the lps.

It’s generally a ttl voltage level (0 - 5v), so you can measure it with a simple voltmeter.

At 50% pwm it should be about 2.5v and 100% is 5v…

I’d check the physical wiring of the pwm signal first…

The ‘door protect’ will show an error on the console if it’s triggered, so I doubt that’s the problem.

All of the sensors can be seen via the ‘Z/U → Diagnostics’ on the Ruida console.

Good luck


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