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MMU Off Switch

by AbeFM Jan 24, 2019
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I do not reccomend cutting power and ground. There are two power leads +12/24V and + 5V. If you cut one of them, the other resists. It is better to cut the communication back to rambo/einsy card. The input has a pull-up resistor and therefore there is no harm to the input. Cut J1/green wire and no response from MMU is transmitted. If you have a two pole switch, the J1/white wire can also be cut (signal to MMU). Thanks for pushing me in right direction regarding setting the MMU in passive mode.

I think you're onto something. Although it would seem if you killed both positive voltages, wouldn't you be ok?

My concern is cutting comms only still leaves the MMU powered up, making noise, possibly getting hot, etc.

I agree,
The cut of both positive voltages seeems to be the best way to go.
I tested with removing the signal lines and here are the motors still engaged.

Your recommendation is to use a Dual Pole switch, and use each pole for each positive (red) cable from the eons board to the second connector on the MMU?

That's what I'm going to be doing. I can't find a direct replacement DPST switch, so I'll update the design to fit these:
https://www.amazon.com/Rocker-Switch-Household-Appliances-MXRS/dp/B07MW2CV4C ("color 9", which should come up)

I ordered some from China but a few weeks later I'm thinking I just should have spent the money to get it locally.

I remixed it for a rectangular switch. https://www.thingiverse.com/thing:3737946

MMU Off switch rectangular

Where can I find this switch?? Or the dual post you mentioned? Links??

Hi, I can totally feel your frustration with the mmu2. After tinkering with it for what felt like ages I only used it in single mode for quite a while. But when I upgraded to MMU2S it fixed lierally every single problem for me, and now I am printing multi-color and multi-material with easy, with no fails in the last 2000+ filament changes. As an owner of the original mmu2 this upgrade is free for you too. Be sure to try it.

I'm looking forward to it. It shipped today. It's the "right" way to do it, was quite the conversation topic on the forums for a while maybe a year ago.

It is another case of PR holding their cards close to their chest, letting the community waste their time on parallel development. I'm looking forward to the improvement but the process would not encourage me to recommend PR products to my friends.

I finally got my mmu2 built. What issues will this hack fix?

Its turns on turning off.

Hey there! Nice design! My MMU2 seems to be working fine-ish (it took me 3 weeks to troubleshoot, but it's fine now), I will still probably make this just because it's pretty useful. Keep it up!