Proffieboard V3.9 pFett Killswitch pads issues

I’ll try and make this long story short. I wanted to use the pFett low current pads on the underside of the V3 board to kill the power to the board.
Using the KR Proffie V3.9 that comes with the resistor pre-installed, I cut the bridge between the pads and checked continuity. After several attempts I finally cut the bridge and continuity was no more.
I then wired in two 30 gauge wires and again check the continuity and there was no continuity. At that point I wired in my kill switch. Which was a standard high amp kill switch normally used.

After finishing the install and throwing in my battery the kill switch did not kill the power to the board. I checked the continuity again and everything checked out but it was not working. I even checked over everything shown in the instructions again just to make sure I didn’t miss anything but I could not get the board to shut off, even with the wires completely removed from the kill switch the board still had power.
And so at this point I said to hell with it and wired in the board like normal and jumpered the pads low current pads and I didn’t think anymore about it after that point.

Once the install was completed I was checking everything out and when I went to check the onboard voice prompted voltage it was saying 3.59 volts. And so I checked three fully charged batteries in the hilt and they were all saying approximately 3.59 volts.
I then placed those same batteries in another hilt and they were all properly reading over 4 volts. So something was definitely wrong.

This led to a very lengthy troubleshooting process that involved everything from changing operating system to SD card and using different configs and everything I could think of to try to figure out the issue. One more note of importance is when I hooked up the USB to the computer the serial monitor was reading over 4 volts . And even the voice prompt was saying over 4 volts, but in the end I couldn’t figure out the issue and pulled the board completely out.

But for the sake of curiosity I checked the voice prompt inbetween every wire I unhooked. Until I was down to just the positive negative from the battery and the speaker. At that point I was checking the voice prompt by Jumpering from ground to aux.
It was at this point when I had the board completely pulled out that I thought about the pads on the bottom of the board. In hindsight it seems obvious to have checked them, but of course they are a new feature so they did not cross my mind unfortunately. So I checked the continuity and I was not reading continuity across the pads.
Which means that my bridge did not take. So I jumped the pads again and at that point my voice prompt started reading over 4 volts. That fixed the issue.

So I guess the main question here is if the bridge between the two pads are severed why does the board still have power? I also have to note that I had about 100 accent LEDs that were all working perfectly fine with out those pads being properly bridged. Even though it read 3.59 volts everything was working as it should including the main blade. Even the flickering issues that everyone has been talking about we’re not occurring. I was using two of the free pads as data lines.
So the main reason for posting this is if this happens to anyone else they don’t have to go through all of the trouble trying to figure out why they are reading low voltage.

Also in hopes to understand why the pads are not killing the power to the board. Thank you

Well, now I have to check if I designed this feature correctly.
The pFET is normally used for reverse power protection, and I think that means that it’s hooked up backwards compared to a normal pFET. If that’s the case, then the reverse diode in the FET would engage when you cut the bridge. This would still work, but would cause a ~0.6 volt drop in voltage.

It would indeed seem like this is not designed right.
That means the low-power switch mode doesn’t actually work. :frowning:

You wrote that you need a FET for low power switches. How does that works?
Does it still works taking out the resistor and using the three wires, or not even then?

Thank you Fredrik for looking into this. I was really hoping I’d missed something.
So leaving the pads alone is the best route to take then I assume? Since they’re already bridged.
Just want to make sure.

I have the same question.

You need a pfet and a way to wire it up. (Possibly a seprate circuit board)
It’s completely separate from the proffieboard.

I have 24 V3.9 board, and have been desiging around the new light switches. Mainly due to space concerns. Which sort of pFet would be required? BTW, this would allow even V2.2 to use the small switches, right?
Could you propose some part that could be easily added? I mean, something small, yet strong enough to handle the Proffie’s power demands?

I posted some recommendations over in the announcement thread. I will also help with circuit diagrams and PCB design if needed to try to make up for this problem.