@dc42 A worthy sacrifice imho, thanks for the heads up.

@dc42 Thank you for this, what a great breakdown and exactly what I was hoping to get. Hopefully it'll be helpful for others looking to do the same in the future. The additional diode, removing the flybacks and jumpers I honestly would have missed I'm sure.

Hopefully I can get some time to give this a run and update. ( understood, at my own risk )

Re: Higher input voltages for steppers

Picked up a duet3 a couple months ago, have been running it in a printer a bit but the real reason I got was to replace grbl on my cnc ( for 5 axis in the, hopefully, near future ). Currently I run 48v on a dual Y axis cnc with a moving gantry and single X and Z motors which I obtained from OpenBuilds a couple years ago
Just wondering if anyone has actually attempted the >=36v mod on the duet 3?

I have a serviceable understanding around electronics and have done a lot of soldering and what-not in past, however I'm certainly no electrical engineer ( went software for the career for better or worse ) Anyways, if someone could chime in that's make me feel a bit better.

Here are the highlights from the previous thread to save you a min:

From @dc42 comment

• The limiting components are the 5V regulator (AOZ1284) and the 12V regulator (TS30041) which are rated to 40V. Some of the capacitors in the 5V and 12V regulator circuits may be rated to 35V only, although I know that we often use 50V capacitors there.

• You can manage without the 5V regulator if you provide external 5V power, however 12V is needed for the TMC5160 driver chips.

• Probably the simplest way to allow up to 48V would be to remove diode D3 and feed between 12V and 30V to the pad that the cathode was connected to, to power the 5V and 12V regulators.

• To go higher than 48V, you would need to replace the six 220uF 50V electrolytic capacitors.

From @nomad comment

• I think the AOD4184A mosfet and the Schottky CDBA540-HF would not be able to work above 40 volts, so the solution of removing the D3 diode and externally powering the regulators can be dangerous. It is right?

  • Answere by @dc42 here

So basically?

1. Remove diode D3
2. Get a 12 - 30v buck converter, wire into the 40+V powersupply, buck converter output goes to diode D3's cathode
   - Suppies power to 12 and 5v regulators, powers TMC5160 and 5v for power to rPi
3. Need to double check capacitors on board to see if they are rated for the voltage?
4. Given the last comment, cannot use "AOD4184A mosfet and the Schottky CDBA540-HF" which isn't a huge deal, since it's a CNC, although would be nice to have if it's a low effort change to get the heater outputs working in the 40+v setup

Thanks to any help/reassurance ahead of time!