@nurgelrot I will be sure to post as soon as I find out! You are correct about the starvation on the Pi side when it comes to a Pi 4 as the power requirements (for the Pi) are somewhere in the ballpark of 5A whereas the Duet is only able to supply 3A max on top of any other peripherals that require a 5v source. The symptoms usually show up as a warning on the Pi.

I have also read about solutions where the SBC can power the mainboard but something about it just feels wrong, also since that LRS-100-5 can supply up to 18A, I figure why not use it to also supply the duet.

I figured with all of the people on this thread it should have been a slam dunk to get an answer by now. I will post my findings if I decide to give it a go on my own. Hopefully I don't cook any boards haha

@gtj0 the power source for 5v is an LRS-100-5 meanwell power supply that I am using to power the raspberry PI. I saw the ext 5v plug on the board but no official docs for it and can’t find a clear answer about how to use it. I don’t need USB access to mainboard as I have an SBC and the SBC connected by ribbon cable. I guess maybe I need to back up a little - is the ext 5v plug meant for supplying the 6HC with an external 5V source? Or is it something completely unrelated?

I found this post when googling for more information about the EXT_5V input and see that this post resolved to the SBC powering the 6HC and doesn't fully address the issue brought up in the title.

In the scenario where I want to supply an external 5v source to my 6HC AND external 5v source to my SBC (Raspberry Pi 4) -

1. Would I use the EXT_5V input to provide an external 5v source to my 6HC?
2. What jumper strategy should I use OR should I just remove all power jumpers?

I would normally just "try" something like this out but really want to avoid damaging my board haha. Any guidance would be greatly appreciated.