Pull off the connector that houses the L wire from the LPS. Make sure that the signal is making it all the way down the connector and nothing would prevent it from making it to the LPS.
Look for any damage at the pins or connector.
It seems to me that individual components are working correctly. Just need to sort out where things are integrating.
Where are you finding any wiring diagrams?
This should be relative simple. Itās probably controlled by a single wire, the pwm.
If the L terminal goes low, it should go to zero, when it needs to lase.
It will probably show a percentage of 5v, depending on what power is requested.
Some kind of diagram would be nice.
Iām not aware of any diagram for this. Iām going off of OPās findings.
Have you seen any other laser wired this way? Itās new to me.
Sorry, i would also like a wiring diagram to be honest. I found that the L terminal was a bit loose but i canāt make it any better, btw if mine does operate by 5V being 0% and a voltage drop causes the laser to fire then could it losing electrical connection cause the laser to fire at 100%?
Iām considering just ordering another power supply, maybe 2, the 5V signal has me confused tho.
Found this from manufacturer
Would the test button tell me much?
Itās not just your laser that pulls L down to Ground to fire. Thatās typical. What I havenāt seen before is where the L pin is simultaneously used to control PWM and it be inverse to typical PWM power values. Normally L would only be used to fire the laser while IN would be used to determine power level with PWM or analog voltages.
A power failure should not fire the laser in any case although itās been known for some power supplies to fail with an active laser.
The fact that the remote test button works makes me think the laser power supply is functioning. You may want to check voltage at L while using the Test button.
These power supplies are commodity items but there are various strategies for how theyāre wired. Any K40 type supply should work although it may be easier to wire if you get one with the same pin layout.
The Test button on the LPS should work the same way as the remote. Give it a try.
Be careful poking around in the LPS.
The test button did not fire the laser. When using the test button up top L showed between 1.1-1.3V even when scaling from the lowest to highest power.
Did you do this through the dial on the remote?
This is surprising. I canāt decide if this is a problem but donāt understand how test button on LPS doesnāt work, the remote test button does work, and signal from LightBurn does not work.
Were you able to confirm that controller signal is making it all the way to the L pin at the LPS?
If you unplug the remote control does behavior change at all?
Yes
I did verify as best as i can tell that making changes in Lightburndoes have a corresponding change in V at the L pin. Tonight i can try to test the pin a bit more specifically possibly? Iāve been checking voltage where the wire comes in to the block up top.
I check that out tonight as well, i went ahead and ordered a spare LPS, but I wanted to have a spare anyways.
I think if weāre going to fix this we should look at it from a different angle.
From what I read, it was workingā¦ attempt to align and it doesnāt work.
We have to assume the machine is wired correctly or it would have never worked. The wiring isnāt going to be changed unless someone does itā¦ not a gremlinā¦ Pretty much, the same with the controller settings.
What signal, could be the door protect for all I knowā¦ 
This adds another variable, since no one appears to know how this work. Lots of speculation but nothing that Iād call, even firm.
Iād suggest a different process to help figure out what is going on.
Do these with the remote panel connected. No need in 1st step for it to lase.
We need to find out what signal is what. A change of percentage power should correspond to a change in one of these voltages. Whichever signal changes with the percent power is likely the pwm signal.
In addition, Iād email OMTech and ask about this board ā¦ get anything they will give youā¦ Do this asap as itās usually a 24hour return timeā¦ Iād include a photo of the control board or they will assume something different. A manual or pin out of itās connectors would be very helpfulā¦
What documentation do you have on the machine, especially the control board connections? Can you post it? If they could provide you with configuration numbers would be great.
If this worked previously, then it sounds like a hardware failure, or a wire is lose. Generally speaking it could only be a ground, L or INā¦
The test button (red) on my lps, although different, doesnāt operate unless I remove the signal connector, on the right.
These seem to operate in three different modes. Which type are we dealing with?
The standard K40 where the operator sets the maximum current with the know and the pwm enables and disables the laser. Running it like a dpssl.
Both of the following allow tube current control via software.
Some wire L to ground via a laser power switch on the console and route the pwm control to L.
Still others, like the C3D mini has a pwm output and a laser enable. This operates the tube properly, the same as the other dsp, like the Ruida.
IMHOā¦
I base this on quite a few years of dealing with Chinese and many low end economy countries products. I have learned they do it cheap, quick and sometimes dirty. They donāt make money making circuit changes and modifications.
Everybody on these boards complain about how 
these cheap products are. Then support what they are doing on other thingsā¦
I think this pot operates just like the standard K40, Ed disagrees. I think he believes they redesigned the circuitā¦ It doesnāt fit with their standard MO.
Even when they do something wrong, they donāt correct itā¦ if it works for the warranty period, thatās sufficient.
You really canāt trust the advise of the technical people on their website trying to support the hardware they soldā¦
Iād suggest checking from the end of the cable, the side connecting to the LPS. Although now that I think about it you checking the voltage of the remote Test button likely confirms continuity from LPS to the top of the block.
I think this is everyoneās assumption until date.
Not following. OP has measured this.
Donāt disagree but OP has measured values.
OP measured this. He showed that change in PWM to IN did nothing. He also confirmed that IN is bridged to 5V and he gets a constant 5V irrespective of power level. He showed that change in power settings in LightBurn correlated to inverse change in voltage to L with 0% power at 5V and 55% at ~2V.
He also showed that changing the dial on the remote changed voltage at L but in a narrow range between 1.1-1.3V. I think the test of voltage at IN while rotating dial on remote could be interesting if it directly affects the 5V.
This is what the focus has been on.
Sounds like this is more the former but OP hasnāt mentioned the L wire being connect through the console.
To me it looks closest to this model.
Based on this exercise Iām wondering in IN and L are actually internally bridged.
I donāt think this could actually be functional.
The IN terminal can be either analog or digital. In the end, it doesnāt matter and resolves into a dc voltage controlling the current limiter.
The L is digital and is active low. Inverted from the IN signal.
Since L is digital input, I canāt see any reason that the pot would change thatā¦?
I agree, thatās where the IN voltage/pot setting question comes fromā¦
My lps has an H terminal, positive laser enable signals. I donāt think the K30 supplies have this.
Itās easily with these to put out an inverted pwm and drive the lps directly. Operating in the dpssl mode.
The range of voltages do not jive or it has a faulty controller configuration, seems unlikely. 55% of 5 isnāt ~2.
I have been e-mailing them back and forth, but I asked for that info specifically.
I posted what I have, it isnāt much
Canāt argue there
So I didnāt record super accurate numbers when I checked that, but while running lightburn, the changes were linear but inverse to Lās 5V signal, the 55% was in the lower 2ās, like 2.25-2.3V or so (I can check again later). I just checked a few different lightburn percentages and saw the trend, sorry for any confusion. And when using the knob with the test laser button (the only way it currently is firing), the L pin was in that narrow 1.1-1.3V range from 2mA-20mA (ish not exact numbers just mean the total range of the test fire).
Also, I noticed that the ammeter screen shows normal info (just no amperage) when lightburn active, laser signal alternating to on and displaying a laser icon as if it were firing, but staying at a current ouput of 00 mA the whole time.
Could you tell me what dpssl mode means? just for my education.
I really appreciate all the help and advice.
Diode Pumped Solid State Laserā¦ the proper term for a laser diode. Sorryā¦ 
The pwm is a modulation method that is frequency (period) independent. A ttl (signal type) pwm is referring to a ttl signal that has a 0 to 5V range. A pwm of 50% will read 50% of the range or 2.5V
The ~2 at 55% should read 2.75V which is 55% of 5V. Somethingās not right here with your values.
Most of these inputs dive an optical isolator. Not sure how you measured the current.
Make sense?
I really should just use google instead of bothering you for definitions, but thank you!
And it appears my L terminal has an inverse relationship with lightburn power, 20% from lightburn correlated to the high 3V range, but i will confirm that later today with more values and record them. The first time i just observed the general relationship and moved on.
For the current i just used the installed ammeter on the machine.
No. But I think youāre thinking on the wrong end of the inversion. 100%-55%=45% * 5 = 2.25. So roughly 2V.
I may be wrong but I didnāt think the commodity blue diode lasers were DPSSL types. I donāt believe they employ any diode pumping techniques.
25% is roughly 3.7V, 50% is roughly 2.5 V 75% is roughly 1.3V with lightburn, measured from L to ground
IN is a constant 5V with lightburn or test button
K+ shows the same as L for lightburn and similar changes when using the knob (5V normally and drops ro around 1.2V when using test and knob)
This makes sense given that both are supposedly for Switch Laser Control.
Can you test one thing?
Can you see if L and IN have continuity?
No continuity, there is continuity between the black 5V wire next to the L wire and IN
Okay. Thanks for checking. Curiosity got the better of me.
Given that IN is bridged to 5V that must mean itās a common 5V for both.
Any suggestions for what to try next?
