Losing/reconnecting connection to Rambo every 11.5 seconds

fbrier

The Raspberry Pi 4B running Repetier-Server 1.4.6 is connected to a Rambo 1.4a, running Marlin, using USB. Watching the Printer Settings connection bar icon, it switches to a disconnected state for 1 second every 11.5 seconds. I measured the disconnecting repeating 3 times, but it happens continuously. What might cause that? The settings the automated connection picked was 250000 baud, RTS Low-to-High, DTR High-to-Low, Ping Pong Mode with an Input Buffer Size of 127 bytes. Thank you.

Repetier

That is the retry frequency when connection does not receive a valid response from printer.

Open second window and go to console and enable ack/commands and see if you get any answers from the printer at all or error messages explaining this. As it tries to connect the port is visible but gets no response.

I know the Einsy Rambo used in Prusa MK prnters always shows the port but only runs cpu when main printer power is available. If that is the case with your board make sure main power is on as well. There is even a switch to not show connection attmpts in this case (Port is visible even if firmware is not running). Activate it if this is the case and it works fine with main power.

If it worked before also check if 5v is still there if there is a hardware defect. If you have a lcd on the printer and it works firmware can be assumed to be running.