Octoprint and Ender 3 Pro display

[bleazenb]

Ender 3 Pro display and OctoPrint connection

Just got Octoprint downloaded to my Raspberry 3B+ and its working fine, only issue is that when I shut my Ender 3 Pro off the display on the printer is still on as long as I have the usb connection between the printer and Raspberry? Soon as I disconnect the cable the display shuts off?? Somehow the display is pulling power from the Raspberry through the USB cable with the printer turn off and even unplugged from AC power?

[Ewald_Ikemann]

Hello @bleazenb !

You may have a look on these:

Printers known to have backpowering issues

Printers that show backpowering issues try to draw their 5v power from devices connected via USB. In the case of a connected Raspberry Pi, that can cause undervoltage issues and thus negatively affect stability and performance - we've seen crashing Pis, vanishing WiFi and so on. There's a simple fix that involves putting electric tape or otherwise disconnecting the 5v line in your USB connector. Here's a list of printer models currently identified to exhibit this electrical design flaw in their…

Put tape on the 5V pin - Why and how

First of all this whole tutorial isn't a mandatory mod - you just need it if you run into issues (weird things are happening and you've already ruled out the more common suspects) or if the always running fan and illuminated display (even when the printer is turned off) disturbes you. I'm starting with the why part: If you connect a 3D printer via USB to your Raspberry Pi it can lead to all sorts of power related issues. Most of the time those issues occur only if you turn on your pi before …

[BML]

Hi I have the same printer and it does the same.
Here is my 2 cents
The RPi is sourcing 5 volts out it's USB port to the printer's controller board which in turn is keeping it semi alive. IMHO, Creality/Ender should not have directly connected the USB 5 volt line to the internal 5 Volt power bus. This is a printer which is a "device" and it does not need the 5 volts from the "host". It is up to the "device" to handle this. The "host" ( normally a computer) has no idea what "device" you are going to plug in to it so it sources the 5 volts on it's USB ports for peripherals like mice. keyboard. hard drive. etc that do require power. A printer is a "device" but it does not require this USB power therefore it should isolate it or have it selectable if there is a need for the printer to act as a "host". Not trying to knock Creality just taking the time to explain this as it is a pretty common issue in the USB world that a lot of designers over look, not just printers.

So the simple and easy method is the tape trick to isolate the 5 volts.

Hope this helps Happy Printing