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Swapping MK3 PSU, max voltage for Einsy Rambo?  

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kirby
(@kirby)
Trusted Member
Swapping MK3 PSU, max voltage for Einsy Rambo?

As a few others have done, I'm replacing the MK3 PSU with a MeanWell LRS-350-24. This PSU has an adjustable output ranging from 21.6-28.8V and I was thinking I might bump up the output voltage a little above 24V to account for some voltage drop under load. So I was wondering what the max input v0ltage is on Einsy Rambo that comes with the Mk3? Any reason not to just run this at 25V? 

 

Posted : 24/12/2019 6:18 pm
rmm200
(@rmm200)
Noble Member
RE: Swapping MK3 PSU, max voltage for Einsy Rambo?

Of course you know you lose the power loss signal doing this, but that is not a big deal.

I have the Meanwell just sitting, waiting for a reason to swap it out. So far - the stock PSU runs the printer, lights, and Pi 3b with no issues.

If it were me - I would run the Meanwell at exactly 24 volts. Maybe trim it under load. It is a switching supply, and output voltage will not vary much.

Posted : 24/12/2019 7:26 pm
kirby
(@kirby)
Trusted Member
Topic starter answered:
RE: Swapping MK3 PSU, max voltage for Einsy Rambo?
Posted by: @robert-rmm200

Of course you know you lose the power loss signal doing this, but that is not a big deal.

I have the Meanwell just sitting, waiting for a reason to swap it out. So far - the stock PSU runs the printer, lights, and Pi 3b with no issues.

If it were me - I would run the Meanwell at exactly 24 volts. Maybe trim it under load. It is a switching supply, and output voltage will not vary much.

As it turns out, I didn't lose the power panic! I used this part from ThingVerse and it reuses both the exiting AC In (an IEC-14 inlet with a fuse and the power panic circuit on the back) and the on/off switch from the existing PSU holder. 

Just tested the voltage while pre-heating for PLA and my LED lights on, got it set 24.45VDC with the probes at at the Einsy input. I'm going to leave it there because the adjustment is pretty sensitive.

Posted : 24/12/2019 10:31 pm
rmm200
(@rmm200)
Noble Member
RE: Swapping MK3 PSU, max voltage for Einsy Rambo?

Hmm. Well hmm..  I like that mount.

I have the MK3S, which has no separate power fail board.

I don't know if my machine has mounting holes in the frame that would work. I may need to print one up and try it...

Posted : 24/12/2019 10:39 pm
kirby
(@kirby)
Trusted Member
Topic starter answered:
RE: Swapping MK3 PSU, max voltage for Einsy Rambo?

Ahh, ok. So it's built into the Delta PSU that comes with the MK3s? I think I remember a post on these forums about moving that over. Or...you can just not worry about it. I wouldn't have gone thru a bunch of trouble, but it was drop-in easy. The hardest part about this was running new PSU wire to the Einsy. I honly had 16AWG cable with a pretty thick jacket and kind or large spade terminals, so getting the cables to bend and routed and then slightly deforming the spades on the Einsy end to get them in the slots. 

Posted : 24/12/2019 10:57 pm
rmm200
(@rmm200)
Noble Member
RE: Swapping MK3 PSU, max voltage for Einsy Rambo?

If I do this - I will treat my printer to good wire - and a good crimped connector. I like:

https://www.amazon.com/BNTECHGO-Silicone-Flexible-Strands-Stranded/dp/B01AO7586O/ref=sr_1_17?ascsubtag=1ba00-01000-org00-win10-other-smile-us000-pcomp-feature-scomp-wm-5&keywords=silicone+power+cables&qid=1577229335&sr=8-17#customerReviews

 

Posted : 24/12/2019 11:18 pm
kirby
(@kirby)
Trusted Member
Topic starter answered:
RE: Swapping MK3 PSU, max voltage for Einsy Rambo?

Nice. I mis-typed above. I ended up using this 14AWG cable and these forked connectors. They're a bit too big to fit easily on the Einsy board, but with a bit of tweaking, they do work.

Posted : 25/12/2019 12:57 am
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