Laser setup issue

Hello everyone,

I have gone through the posts here and on facebook (as well as other places) and am still stalled out. Hoping I can get some advice. I believe I have wired up my 5W Banggood laser correctly having followed the Longmill laser tutorial as well as changed grbl settings to what others have used with success. I have power to the fan and a beam when I click the “positioning” button on the laser driver board (light on board goes from solid red to blinking) and after connecting to Lasergrbl I am able to jog the machine and have it jog when running a file but the laser doesn’t fire. Also, not able to get the beam when using Lasergrbl custom buttons. Based on this, I am assuming I also have the wires (polarity) correct to the PWM otherwise the machine wouldn’t jog. Am I right in assuming this? Thanks in advance for any advice you can shoot me. Cheers!

@Danny Welcome to the group, Danny.

With respect, your assumption is not correct. The pwm only controls the power of the laser. it has nothing to do with jogging. Take a look at your connection to the pwm port on the mill controller and confirm that you have the polarity correct.

Does your laser’s board have two connections for pwm? Mine has a single wire connection that is a part of the power cable and another two pin port on the board itself. If yours is the same, which connection are you using?

You may want to give LightBurn a try. You can use if free for 30 days.

@gwilki thanks for the reply. That makes sense now about the PWM not controlling the jogging. Someone straightened me out on that last night haha. As for the connection to the PWM, I am not using the single wire adjacent the power, rather the two pin female connector on the board. I had to source the male pigtail connector from a hobby shop. I initially (first way) went to ground from LM to the neg on the laser board and PWM to the positive on the laser board which made sense to me but when I hooked it up there was I high pitched noise coming from something and the laser came on at what looked like full power. Luckily, I had my glasses on! Did yours do that when you first wired it and powered it up? I changed them around (second way) and plugged it in and got no noise which led me to believe this was right. it had a steady red light on the board and when I clicked the button on the board, that red light would blink and the laser turns on at low power for what I assume is for lining up x, y. Also with it wired this way (second way) I had the same behavior as someone else in the forum who stated (if I understood correctly) that this made sense and is correct and when they unplug the connector to the PWM like I did after wiring it the second way, the laser turns on full just like when it was wired the first way. so does that make sense? It is saying to me that having it plugged in with the polarity backwards is the same thing as them not being plugged in at all. I think I will try Lightburn and see if it makes a difference. I hope I didn’t make this more confusing. Any insight you could give me would be really appreciated. Thanks again for the input! Cheers!

@Danny I’m not familiar with lasergrbl. What do you have the S-max setting set to? On your Mill controller, what do you have the $30 parameter set to? They should be the same and I suggest that you set them both to 1000.

Hello again and thanks for the reply. I have tried both $30=100 and $30=1000 based on others’ advice. Also I tried several different combos over the 8 hours I worked on this yesterday but I believe the “S” was set to 100 while setting up a test burn. Are you saying the laser won’t fire if these values are not identical? I’ll give it a try but I may have had those values the same at one point with no resolve. Thanks again. I’ll let you know if that helps. Cheers!

@Danny The laser may fire. The problem with be that, if those values are not the same, you will not be able to know with any precision what power that you have set. The recommendation seems to be to set both to 1000. Since there seems to be no reason not to do that, that’s what I have done. You can experiment with other values, but I would strongly suggest that you keep them both the same.

@Danny @gwilki - Grant I think Danny may be confused a little. Either that or I am. Danny, as Grant says, set $30=1000 and $31=0. Since $30 is set to 1000 (maximum) power, set the “MAX” setting in LaserGRBL or LightBurn to 1000 also. As Grant said if those numbers aren’t the same you will get unpredictable results. The “Sx” value in the gcode controls the variable output power values. If I am off base please disregard this post.

Hello again Heyward and thanks for the reply. You are right in that I am a little confused haha! What you guys are suggesting regarding settings is exactly what others have suggested (some say 100 while others say 1000 as long as they match right?) which is I believe how I began setting this up in the first place. I know you guys are right on this but after following those suggestions without success I began to wonder if I had something else set wrong or something else hardware-wise was defective. I will try again from scratch this weekend as it’s more than likely I did something wrong. Can’t tell you guys how much I appreciate the help on this. Cheers!

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Good morning everyone,
Thanks again for all of the previous help. I have double checked my settings ($30=1000 which is the same as the S#) and I have downloaded) installed the trial version of Lightburn and done the same. I still have an issue with the laser only working when I activate the button on the board. In Lightburn, I tried the test fire button at 20% and also tried running a simple job with no results. I don’t believe I am confused on these settings. They are straight forward and I’ve double checked them several times. The only other thing is polarity on the PWM wires. Wired the first way, it makes a squealing noise and the laser fires at 100% and wired the second way (the opposite) it behaves (I believe as it should (laser fires when I hit the physical button on the board) except when using the software. I am throwing alot of hours at this and can’t help but wonder if I’m wasting my time going over the same settings and start looking at a hardware problem. This Banggood laser has been known to ship and be defective and I have read that on rare occasions the Longmill board has been the culprit. If you all had the same issue and we’re sure you’ve entered the correct values and have it wired correctly, what are the next steps for diagnosis. Thanks in advance. Happy Thanksgiving!

@Danny - I do believe several people have had these same or similar issues. The only person I remember is @gwilki. He ended up getting a replacement from Banggood. Also there were others that had a problem closer related to yours. Those I believe turned out to be issues with the longmill controller. Don’t quote me on these but I think I am right. I’m quite surprised nobody else has jumped in to help you. Only other contacts would be @andy or @chris at Sienci to see if they have any ideas. Keep us posted please.

Hello Heywood,
Thanks for the reply. I have had @gwilki and yourself reply with some useful tips and he straightened me out on the pwm having nothing to do with my ability to jog. I should ask him what he did to prove the laser board was the problem and what Banggood wanted from him before they would send him a new one. Ill keep you posted and also let you know what the issue is as soon as I know. I think for the rest of the day I will service the Longmill and start cutting some more shaker door/drawers and keep moving my kitchen forward Thanks again Heywood and Grant.

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@gwilki Hello Grant, Thanks again for replying and helping me with this thing. I am fairly positive I have all of my settings correct and believe its time for me to start ruling out hardware, I am thinking I have a an issue with the laser board not communicating with the laser via the PWM. I would like to know how you were able to narrow it down to the laser board that Banggood replaced for you. I was thinking I would make sure the signal was leaving the LM and getting to the laser board but from what I read, one needs an oscilloscope for this which I do not have. P.S. I have tried to fire the laser using commands (M3 S255) via Lightburn as well as the Arduino IDE and dont get anything. Anything you could offer up would be greatly appreciated. Thanks in advance Grant!

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@Danny Danny. Before I get into my long sad story with Banggood, I’ll direct you here:

In that thread, Paul shows that you do not need an oscilloscope to determine if the pwm controller on the longmill board is behaving. I followed it and found that mine was.

You should also read this thread:

Once I followed Paul’s advice and saw that my LM controller was fine, I had to conclude the laser was defective. I’ve already set out the steps that I had to go through to get Banggood to replace it. It was not fun. I will never deal with them again. I did finally get a replacement, though.

That is a tonne of good info there. Also some portions of threads I somehow missed. Thanks for taking the time to put it together. Gonna start chewing on it when I can. Cheers!

Hello Heyward, this reply has nothing to do with my laser issue. I just noticed that I have been writing “Heywood”. Feeling stupid! My apologies as I meant no disrespect. Cheers!

Lol, no problem Danny. You would probably be surprised how many people do that. I think Heywood was a more popular name than Heyward. My last name is worse. Only 1 in 50 get it right. No need to apologize.

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@Danny There are now several threads on here talking about our collective trials and tribulations with lasers. As a result, it’s very easy to miss stuff. That’s why it’s good to have group participation. :grinning:

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I just received by Banggood laser and am awaiting my LM to ship (hopefully tomorrow). I really appreciate everyone sharing their experience and advice here, fingers crossed that this laser will work out. It’s worrying that there seems to be such a high failure rate out of the box with these from the messages I’m reading here and on the FB group.

@westsidewood I’ll think good thoughts for you. You can do the first test of the laser before the Mill arrives. Connect the laser driver board to its power supply and the laser module. It should fire full power. Then, press the small button on the board and the power should reduce to near nothing, with the red power light on the board blinking. If all that works, you’re almost there.

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Thanks for that - the laser works as you described so far, so I’ll hope the odds stay in my favor. Just got my tracking number so hopefully I’ll be able to test out the PWM control next week.

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