Raspberry supplies power to my printer main board.


Even if my printer is turned off and it is connected to my Raspberry the main board and display is on.

Is it possible to prevent the Raspberry from powering the printer main board.
With this situation it’s a pain to just reset my printer. I have to unplug the USB and then turn off the printer.

My printer is the Ender 3 v2

There is a way; use a USB switch to cut the +5V supply from the Pi to the printer. DrVAX mentioned them in 1 of his videos. Here’s 1 example: [U]Amazon.com

Perfect - Thanks

Most welcome

Don’t cut wires, put tape over the power pins!


The USB Power Switch doesn’t require any cutting of wires.

I just scraped the 5V pin from the usb cables with a knife. Another plus of the SKR boards, as they have a jumper for this.


As you can see, if you hold the round side down, it is the bottom right connector you want to remove. Just use a knife or a small drill to get below the track and once you are below you usually can break the pin using a screw driver and pushing it inwards.

Does not look pretty, but it works fine and is a cheap solution done in minutes. Just make sure you mark the cable as „no Power“ or you may run into issued in the future, when the cable ends up in a usb cable storage. :slight_smile:

Does the jumper permanently block external power?

Yes, it selects between usb power and the screw connector of the board.

I added an image and instructions above on how to remove the pin from the cable to achieve the same with any board.

I have an SKR 1.4 Turbo board coming, so the jumper is likely what I will use.

The „dual“ power situation may even dangerous for the power supply and the hardware, as in off state not only the board gets driven over the 5V USB port, but also the chopsticks and the motors.

When using two power supplies the voltages may be on a different ground level (potential), so the combined voltage could even be higher than 5V.

I have my raspberry pi’s connected to the standby rail of the atx power supply. That way it is always powered. The printer is connected to the normal 12V/5V rails and two resistors and a transistor do the on/off job the same way a pc main board would do, but the PI acts as the power button. Therefor I needed to cut all my power lines in the USB cables. Well all but the one on the GeitPrinter, because of the SKRPro board.

I bought this one from TH3D (and its the one DrVax suggested getting) works very well. Thought about making my own but by the time i bought the parts and printed an enclosure for it it would cost more then the one i bought from them. https://www.th3dstudio.com/product/p…power-blocker/

That’s an interesting approach to the problem. I think I would prefer the one I linked to, but this one should certainly work. After all, it only has to stop juice on 1 wire.l

I agree that the dual power is not a good thing.
I just took a knife an cut the power wire on the usb cable. Taped it back up to make sure the cut wire will never short and it works perfect.
The wires are really tiny.

By the way this one will not work for transfer data it only has the power wires in it not the data wires. Check out the reviews on it.

Try this: USB-A male plug pin isolator (back-power blocker) by magnurz - Thingiverse

Thanks for that. I didn’t check, assuming it had all 4 wires (well, 3 wires :slight_smile: ). Something to keep in mind for sure.

Did it doesn’t work, to thick causes the data connections to be intermittent.

In your slicer, try using the Z axis (assuming it’s printed large side down) to reduce its height before printing. Just be sure to uncheck the option that reduces all axes.

Its only 2 layers thick as it is ?