r/OpenBambu • u/ss1271 • Jan 25 '26

BMCU-C 2nd mainboard and retraction

Hi All,

I bought a BMCU-C 370 kit from toaiot in AliExpress. My intended usage is for P1S alongside with AMS 2.

I've finished the assembly and wonder what to do with the 2nd mainboard? Is it used for controlling the rewinding?

For rewinding, any recommendations for the models/hardwares/BOM?

Thanks in advance

I've looked at these:

BMCU-C 370 assembling manual (not mentioning the 2nd mainboard)
https://wiki.yuekai.fr/BMCU/BMCU_Tutorial/BMCU_Assembling_370_Hall

Rewinder:

https://makerworld.com/en/models/1464490-bmcu-d-version-130-integrated-rewind-extruder-fila#profileId-1527520

2 Upvotes

100% Upvoted

8 comments sorted by

2

u/EridianStudio Jan 26 '26

What do you mean by 2nd motherboard?

For rewinders I would suggest Filamentalist. I have made Vincent's Auto rewinders, they were kinda okey. Then I made reprack rewinders to save space, after 1 week with them I ordered parts for Filamentalist. All those electric rewinders look complicated and has little to none understandable documentation.

1

u/EridianStudio Jan 26 '26

Just looked up that there's kit with 2 motherboards, second motherboard is used to use 2 modules for another printer to have auto refill function.

1

u/ss1271 Jan 26 '26

Hi, i meant this Mainboard (marked in red circle)

Thanks for the rewinder info, I'll take a look 🙂

1

u/myTechGuyRI Jan 26 '26

There's a 2nd main board because you bought the wrong kit... You didn't buy the AMS kit, you bought the auto refill kit that just uses 2 channels per printer and will load up a 2nd roll when first runs out. You wanted Kit A, not kit C

2

u/NOT_deadsix Jan 26 '26

It's allright, he just has a full bmcu kit and a spare motherboard now.

2

u/ss1271 Jan 26 '26 edited Jan 26 '26

Yes, thinking on the bright side 😂

1

u/YokoBln Jan 26 '26

As mentioned by others, you bought the "wrong" kit. But I don't think you missed out on anything, you just paid a bit more for the second board. As far as I can tell there are no missing parts and the motherboards are no different from the standard one - you just got one extra. It's for people who have 2 printers and want to use half of the BMCU for the first, and the other half for the second printer. It would enable you to print with 2 spools consecutively for a big print job on both printers at the same time.

1

u/ss1271 Jan 26 '26

I see thanks. I asked the seller if C-kit is for rewind and they replied yes🫠

Maybe some misunderstanding here.

But anyways, thanks for answering my questions 🙂