Hi, I was hoping someone might be able to point me in the right direction with regards to an issue I’m having where my laser tube has stopped firing. It’s a 60w tube with a new power supply on a Chinese machine. When I press the pulse button it doesn’t fire. When I press the test button on the power supply it doesn’t fire but when I press the pulse button and test button together the tube will fire?
Any help would be greatly appreciated
Mick
Has the new lps ever worked?
The interface is fairly simple between the controller and the laser power supply (lps.)
Beside P for Water protect, which should just be grounded at the lps.
The other two lines are the IN for setting the current level, this can be a digital pwm type input or a direct analog voltage. A pwm input is converted internally to an analog voltage in the lps anyway. The Ruida will produce an analog and digital output for this.
L is used to enable it to lase at the specific input voltage set by IN. When the Ruida runs a layer, it produces pwm the entire time, L is used to cause it to lase.
Interesting combination, don’t think I’ve ever tried both buttons simultaneously. However, the test button causes the machine to lase at 100% power. I’d initially say, the pwm is failing somewhere from the controller → lps. Check both, LPWM1 and L-AN1
On mine, you have to pull the signal controls connector out (red marks) for it to lase with the test button.
Do you have a voltmeter or scope? Even with a voltmeter you can examine the voltage from the controller, either at the output of the controller or at the lps, same wire different ends. If you getting a bad pwm, the analog output might work. The controller uses only one, the LPWM1 or the L-AN1 on CN5 connector. It’s a TTL signal 0 to 5V, so at 50% power it should read 2.5V…
If you don’t understand something, you need to ask, we’re not dealing with rocket science.
Hope this makes sense?
Hi Jack,
Thanks very much for your comprehensive reply. I ended up re-making all of the connections using ferrules with the correct crimping tool and it’s working again. Its seems it may have been a bad connection which might explain why it was intermittently occurring. I learned a lot from your reply which I really appreciate.
Thanks again 
Mick
A lot of times, they put these wires into connectors then use a dash of hot glue. I’ve found more than one they didn’t tighten down the screw and just pulling on it it came out.
Intermittent issues are the worst to debug and fix.
Good luck.
