12v Fans on 24v Maestro question

[PuterPro]

So today I am switching my CR-10S Maestro setup to 24v with new steppers and heater, but plan on leaving the fans at 12v.

Following this guide:
https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans#Section_Using_12V_fans_when_VIN_is_24V

and the Maestro Wiring Diagram:
https://duet3d.dozuki.com/Wiki/Duet_2_Maestro_Wiring_Diagram

I wanted to be sure I was following the Wiki right. I plan on using the #2 solution.

If I'm reading this right, you need to do this:

1. Remove both jumpers from V Fan A Jumper Select and V Fan B Jumper Select to allow external voltage input.
2. Take the + (positive) Buck regulator OUTPUT and run it to both V Fan A Jumper Select & V Fan B Jumper Select middle pins (V_Fan_A & V_Fan_B), supplying the 12v fan voltage.
3. Wire the Buck Input and output - (Negative) to Gnd (I'll probably use the power block Gnd)
4. Pull Buck INPUT + power from the VIN pin of either V Fan Jumper Select (although I suppose VIN at the power block works too, no?)

Note that I have already adjusted the Buck reg to a 12.1vdc output when hooked to the 24v power supply on the bench.

Sanity check please? Thx!

Here's a lousy quick sketch I did on my Note 8:

[JadonM]

Yes, that all looks good. Just be sure to test your buck output for 12V before you hookup your fans.

[PuterPro]

@JadonM > "Note that I have already adjusted the Buck reg to a 12.1vdc output when hooked to the 24v power supply on the bench."

Did that already! I try not to get caught by the obvious, but ... sometimes it bites you in the a**
Hence this post, LOL!

Thanks so much for the verify!

[PuterPro]

I just recalled that @Phaedrux had mentioned that I could use the 12v from my second power supply (I am keeping the 12v supply to power the bed), no Buck regulator needed.

That means I can drive the fans power by running Positive 12v to either V Fan Jumper Select pins, Yes?
Do I have to do both V Fan Jumper Select A and B as illustrated (I assume they're separate since there's seperate jumpers).

[dc42]

@puterpro said in 12v Fans on 24v Maestro question:

That means I can drive the fans power by running Positive 12v to either V Fan Jumper Select pins, Yes?

Yes, if the negative outputs of the 2 powers supplies are connected together.

Do I have to do both V Fan Jumper Select A and B as illustrated (I assume they're separate since there's seperate jumpers).

Yes, if you want all the fans to use 12V.

[PuterPro]

@dc42 said in 12v Fans on 24v Maestro question:

Yes, if the negative outputs of the 2 powers supplies are connected together.

Yep had that one. Was just being overly cautious, as I always am when wiring power, don't like when the magic smoke appears

I'm up and running with my new steppers, heater & 24v P/S. Fans & bed on 12v supply.
PID done, now off to fine tune steps.

Thanks so much David, you're the best!