# Diode laser on a LM Mk3 **URL:** \ **Category:** šŸ”„ Laser\ **Created:** [September 27, 2026, 7:47pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169 "2026-09-27T19:47:40Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [September 27, 2026, 7:47pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/1 "2026-09-27T19:47:40Z")
Has anyone with a Mk3 been able to get a diode laser to work? If so, could you please post your firmware settings? Iā€™m striking out. Thank you. ---
**Author:** ![\_Michael](https://forum.sienci.com/user_avatar/forum.sienci.com/_michael/32/2962_2.png) [@\_Michael](https://forum.sienci.com/u/_Michael)\ **Post date:** [September 28, 2026, 12:47am UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/2 "2026-09-28T00:47:15Z")
I wonder if itā€™s related to this. > [@No power at laser output connector](https://forum.sienci.com/t/no-power-at-laser-output-connector/27030/9): > > Are you running the stock firmware? Awhile back I flashed grblHAL, built with the grblHAL web builder, to my SLB on my LongMill Mk1. Everything was working fine until I needed to use my laser. I couldnā€™t get it working and wanted to proceed with my project so I flashed it back to sienciHAL and my laser worked again. I donā€™t know if I missed something in the web builder configuration or the settings somewhere in gSender but I got it working pretty quickly when I switched back. My laser is 3rd ā€¦ Just to be clear I had built the firmware using Sienciā€™s LongMill Mk2 profile. Now there is a LM Mk3 profile on the [Web Builder](https://svn.io-engineering.com:8443/index2.html?dev=1) as well. ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [September 28, 2026, 2:05am UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/3 "2026-09-28T02:05:49Z")
@_Michael Tks, Michael. I have done nothing to the stock firmware that came loaded on the Lite controller. The available firmware settings are no where near those available on the SLB. Since there is no documentation on the Mk3 or the Lite, I canā€™t figure out which of the few settings that do exist will get this up and running. Who knows? Maybe this is yet another function that wonā€™t be available until Sienci releases the expansion board. šŸ˜’ ---
**Author:** ![KGN](https://forum.sienci.com/letter_avatar_proxy/v4/letter/k/c77e96/32.png) [@KGN](https://forum.sienci.com/u/KGN)\ **Post date:** [September 28, 2026, 2:29pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/4 "2026-09-28T14:29:10Z")
I think Nikhila is looking into this for you (I assume it was your ticket), but Iā€™d start with the EXT2 laser settings for the new firmware and go from there - it sets up various PWM 2 settings including min/max, laser enable, and PWM frequency. It should be in-line with the MK3 since both are modern grblHAL over sienciHAL > **[Technical Manual - SuperLongBoard](https://resources.sienci.com/view/slb-manual/#laser-settings-configuration-files)** > > This document is the ā€œSLB/SLB-EXT bibleā€ for any of the answers you might be looking for when setting up your new controller. This includes sections on all the features, their pinouts, associated settings, and other things you should know when... If you want to verify against your current settings: ![image](https://forum.sienci.com/uploads/default/original/2X/9/906f57926d4875cf675e2a0b886bc15b30f5cdb2.png) ---
**Author:** ![\_Michael](https://forum.sienci.com/user_avatar/forum.sienci.com/_michael/32/2962_2.png) [@\_Michael](https://forum.sienci.com/u/_Michael)\ **Post date:** [September 28, 2026, 6:10pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/5 "2026-09-28T18:10:21Z")
I was thinking they might be related if the Mk3 isnā€™t using sienciHAL because it was when I tried grblHAL that I couldnā€™t get my laser to work. Since sienciHAL hasnā€™t been updated since 2023 as far as I can tell, I thought it was a reasonable assumption that the Mk3 is using grblHAL and now Kevin has confirmed my assumption. I also noticed that some of settings were missing and/or the numbers changed between sienciHAL and grblHAL. Itā€™s entirely possible, maybe probable, that I just couldnā€™t figure the settings out and the firmware was fine. I realize I didnā€™t do a good job in my first post in explaining why I thought they might be related. You should see how bad my communication sometimes is face to face. šŸ¤Ŗ With my ADHD Iā€™ll get exited about something and my brain races ahead of my speech and all that comes out is broken sentences! Writing helps with that somewhat, but not always. ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [September 28, 2026, 6:28pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/6 "2026-09-28T18:28:55Z")
@_Michael I appreciate your help and advice while I work out my involvement with the Mk3/Lite combo, M. Thank you ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [September 29, 2026, 8:09pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/7 "2026-09-29T20:09:08Z")
@KGN Tks for that, Kevin. I checked and changed the settings that were not according to your screen cap. A test burn went well. Iā€™ll close this thread. ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [September 29, 2026, 8:09pm UTC](https://forum.sienci.com/t/diode-laser-on-a-lm-mk3/27169/8 "2026-09-29T20:09:12Z")
Closed on September 29, 2026, 8:09pm UTC