Hi All - Just completed build of my MPCNC and doing the movement test with the LCD connected to Rambo 1.4. Z works fine, but on X and Y, only the first motor is moving as expected on each axis, the Second ones connected to E0 and E1are not moving at all. I do have the 4 ends tops wired in. I am Using the Rambo 1.4 Kit ordered from V1.
Thanks,
Jeff
Your rambo might be flashed with the serial firmware. You can find the version number on the screen, or by sending M115 from repetier host.
513S is serial firmware
513D is dual MPCNC firmware
513DL is dual Low Rider firnware.
If you have the wrong one, it is easy to flash. You can use xloader, or platformio and get the right firmware from MarlinBuilder releases.
Historically this problem would occur when the wrong firmware was installed. Serial wiring and serial firmware only use three drivers (X, Y & Z). It is my understanding that V1 is no longer shipping any sort of serial firmware or wiring harness, so if you made the purchase recently, this is unlike to be the problem. Still, you should take a look at the version on the display when you boot the control board. It should have a ‘D’ at the end meaning dual endstop firmware.
Another thing you can do to troubleshoot the problem is to swap X1 and X2 as well as Y1 and Y2 connections at the control board and re-run your test. If the problem stays with the same motor, then it is highly likely a wiring issue. If the problem moves to a different motor, then you have a firmware or possibly driver issue.
You are correct, it shows it has 510S…Will work on the firmware update.
Thanks,
Jeff
I did just receive direct from V1 last week, but does appear it is loaded with 510S. Thanks, Jeff
Oh man…I shipped so many with the wrong firmware. CRUD!
33 to be exact.
I’m on that list 
Replacing broken Rambo with new and was struggling with the same thing. E0/E1 motors would not move. Checked now and the version is also 510S. Off to figure out how to flash now.
The links above worked great, Took about 1/2 hour including all the large downloads. I did the platformio option.
I sent an email out to every person I shipped one of those boards to and it has a list of options and all the links you will need. Have a look at your spam box.
Upgraded with xloader, all good now!