Octoprint connection to MKS gen l v2.1 with PowerSupply

Hi Octoprint Community,

it's not possible to connect my Octoprint (Raspberry Pi) with my new "MKS Gen L V2.1" board.

If the Pi supplies the board with power, everything works so far. Octoprint and Marlin are talking to each other.
As soon as I switch on the power supply (on the printer), Octoprint loses the connection.


Anything in the terminal or just a connection timeout?

Logs or a copy of the terminal would help

Recv: T:20.50 /0.00 B:22.30 /0.00 @:0 B@:0
Recv: T:20.50 /0.00 B:22.19 /0.00 @:0 B@:0
Recv: T:20.72 /0.00 B:22.58 /0.00 @:0 B@:0
Recv: T:20.69 /0.00 B:22.42 /0.00 @:0 B@:0
Recv: T:20.28 /0.00 B:22.03 /0.00 @:0 B@:0
Recv: T:20.37 /0.00 B:21.80 /0.00 @:0 B@:0
Recv: T:20.44 /0.00 B:21.84 /0.00 @:0 B@:0
Recv: T:20.66 /0.00 B:22.46 /0.00 @:0 B@:0
Recv: T:20.72 /0.00 B:22.62 /0.00 @:0 B@:0
Recv: T:20.47 /0.00 B:22.15 /0.00 @:0 B@:0
No response from printer after 3 consecutive communication timeouts, considering it dead. Configure long running commands or increase communication timeout if that happens regularly on specific commands or long moves.
Connection closed, closing down monitor
Changing monitoring state from "Operational" to "Offline"
Changing monitoring state from "Offline" to "Opening serial connection"
Connecting to port /dev/ttyUSB0, baudrate 250000
Changing monitoring state from "Opening serial connection" to "Connecting"
Connected to: Serial<id=0xa8fc0870, open=True>(port='/dev/ttyUSB0', baudrate=250000, bytesize=8, parity='N', stopbits=1, timeout=10.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
Send: N0 M110 N0125
Send: N0 M110 N0

FWIW I would avoid this situation. Not only is the Pi very 5V power sensitive but you could suck to much power from it.

Try disabling the 5v pin on the USB connection. This sounds like some weird electrical issue caused by backpowering.