I have an Altmill 4x4, and am using Gsender 1.6.0 and I went through the Common laser issues post and Chrises video. The laser turns on and off properly but checking the voltage at the output of the SLB when test firing is always at 4.7 volts. I have changed both sliders (right under the laser test button under Spindle/Laser tab and in the center bottom of the screen). I am using the Jtech 64w laser
@checkers What is your $743 value?
the $743 is set to 0
@checkers I didn’t really think that it could be that easy. 
So, when you send a command to run at 50% power or 25% power, the output remains the same, yes? If so, how are you sending the commands?
Has it ever worked properly?
Just curious … is the output actually zero when the laser is off?
A lot of stuff is switched on the ground side rather than on the high side …
that is correct, regardless of power setting i am getting 4.7v when the laser is commanded on. i tried adjusting the power with the slider under the test fire button and the slider in the bottom middle of the screen. no this is a new setup it has always run this way
it is at zero when off, the on off is working correctly just the power % is not responding to changes
@checkers How are you sending the % power commands? Are you just using the sliders? Have you tried sending commands using the console?
Here is a link to an excellent “tutorial” from Paul Larsen on how to measure PWM output.
If you have not tried testing power this way, you may want to.
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yes I was just using the sliders, just tried using the command prompt and that seems to work. if Icommand m3 s10 I get .78v, m3s50 is 2.68v, and m3s100 is 4.7v. but if I run a test of 3 blocks at 10, 50 and 100% it just goes full power the whole time. (I am using light burn software and exporting the gcode to use in gsender )
@checkers OK, you seem to be making progress. In lightburn, what is your Smax value?
In gSender, what is your $730 value? They must be the same generally either 255 or 1000.
In the gcode that you export from lightburn, what is the laser on command - M3 or M4?
What happens if you just run the file in LB, that is don’t export the code to gSender?
That seems to have done the trick! my Smax values were different I set them both to 1000 and now the intensity is changing as the program runs. i think my gcode is using M4 as a laser on, I am not very fluent yet but there is an M4 near the top but no M3 in the code. is that significant? thank you for all the help!
@checkers I’m glad that you got thing worked out. As I understand it, we want to have M4 turning on the laser. M4 allows variable power settings. M3 does not. I stand to be corrected on that by those who know much more about this than I do. @paullarson is my guru on all things laser, so I take no credit for helping you fix this.
Have fun with your laser.
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You are to kind, Grant.
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