Doh! Newbie Mistake

[DaveRNZ]

I hate being called a newbie It is my mistake though. The diode D1 is inserted back to front.
This diode is to protect the board and Pi if the 12V is put around the wrong way.
The good news is that the board will work fine on 5V if you have it on that power board or if the diode is bridged out with a wire link or swapped around.
You can still run 12V pixels when running the board off 5V. There's 4 separate power inputs for the 3 pixel outputs and the board+pi.View attachment 20940

Thanks Alan, will the 5v drive the Pi as well? I will still need to fuse the 5v input line with a 2a fuse correct?

 

[AAH]

Thanks Alan, will the 5v drive the Pi as well? I will still need to fuse the 5v input line with a 2a fuse correct?

Yeah the 5V will drive the Pi. A 2-5A fuse is all that's needed.

 

[DaveRNZ]

Yeah the 5V will drive the Pi. A 2-5A fuse is all that's needed.

Excellent, thanks.

 

[DaveRNZ]

Sorry to resurrect this thread, I‘ve picked this up again (way too busy at work the last few months!). Finally got some time today to get this working again.

Setup is:

300W ATX power supply, I have connected a +5 and GND wire from the ATX connector into the +5 and GND on the PiHat and jumping the green to GND on the ATX connector to get the PSU starting.

First test was with a 5A fuse, no life from the Pi. Testing the terminals I have 0v coming over it. If I remove the wires to the Pi and test again, I get 5v.

So I switches to a 2A fuse, powered on and the fuse blew immediatley.

Seems I’ve isolated to the Pi causing some weirdness. Anything else I should be checking or doing?

EDIT: using the USB power to the Pi works, as long as the hat is removed.