# Schematic for Lonmill MK1 1.4.2

**URL:** <https://forum.sienci.com/t/schematic-for-lonmill-mk1-1-4-2/27217>\
**Category:** ❓ Something's Up\
**Created:** [October 5, 2026, 2:02pm UTC](https://forum.sienci.com/t/schematic-for-lonmill-mk1-1-4-2/27217 "2026-10-05T14:02:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![viclick](https://forum.sienci.com/letter_avatar_proxy/v4/letter/v/cc9497/32.png) [@viclick](https://forum.sienci.com/u/viclick)\
**Post date:** [October 5, 2026, 2:02pm UTC](https://forum.sienci.com/t/schematic-for-lonmill-mk1-1-4-2/27217/1 "2026-10-05T14:02:07Z")

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Hi folks. My spindle control intermittently fails. I can troubleshoot it but I can’t find a schematic of the MK1 Longboard. Is there one available?

Thanks

Vic

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**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:** [October 5, 2026, 3:07pm UTC](https://forum.sienci.com/t/schematic-for-lonmill-mk1-1-4-2/27217/2 "2026-10-05T15:07:33Z")

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Have you found this page?

> **[Open Source & Modifications 🥽 - LongMill CNC](https://resources.sienci.com/view/lm-open-source-and-modifications/)**
>
> Open source documentation for LongMill CNC and its accessories, which includes 3D files, bill of materials. Community modifications and designs also found here.

It doesn’t have 1.4.2 though it does have links for 1.2, 1.3 and 1.4.3. There is also a link for this [BOM for the LongBoard](https://docs.google.com/spreadsheets/d/10HOJIfVh_pb41V6eJ3zf50yBgs8vmk5MnvHfNH4q9_Q/edit?gid=14760217#gid=14760217). It looks to me like 1.4.2 and 1.4.3 might share the PCB design based on the BOM. I downloaded the 1.4.3 zip, it has lots of files, but I don’t have the programs to open schematics, nor would the schematics make any sense to me if I did!

Hope this helps.

Oh, and welcome to the forum! 😁 It took almost 6 years for your first post so I’m guessing your mill has been good to you!

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**Author:** ![Spamming\_Eddie](https://forum.sienci.com/user_avatar/forum.sienci.com/spamming_eddie/32/7296_2.png) [@Spamming\_Eddie](https://forum.sienci.com/u/Spamming_Eddie)\
**Post date:** [October 5, 2026, 3:37pm UTC](https://forum.sienci.com/t/schematic-for-lonmill-mk1-1-4-2/27217/3 "2026-10-05T15:37:20Z")

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Hey Victor,

As far as I know, the longboard consists of the motor drivers and a seated arduino that is the i/o centre of the longboard contraption. I dont have a schematic either nor have I found any on github. I did have had a quick looksy at my own longboard and didnt think it was more than what I described above.

I think the arduino is the thing you want to look at. The longboard itself is merely an adapter board that does not bring much to the table conserning brainpower.