I purchased my Makerfarm i3v 12" a few weeks ago and set it up. I was able to attach the board to my computer via USB (Jumper on USB POWER) before hooking it up and program it no problem. I then switch the jumper to standalone and plugged it in. The display worked and the motors all moved correctly. However, as soon as I attach the usb cable to the board to begin printing stuff it shorted out and I had to get it RMA'ed. (It wouldn't turn on after that and even after disconnecting everything and returning the jumper to USB power the computer said the usb device was drawing too much power and turned off the port.)

I figured it was something weird with the board, but I just did the same thing with the RMA. Hooking everything up works fine. All the motors move, display works, everything handles correctly. However, the moment I hook it up to the usb port while it's on standalone, the board fries and now nothing works. (Hopefully I'll get another RMA. I would understand if they deny me.)

Anyone know what I'm doing wrong? Are the RUMBA boards not supposed to be attached to a computer while printing? Am I supposed to keep it on USB power if I have the usb cord attached?

I really don't want this to happen again. Any advice would be appreciated.

I'm using this usb hub: http://www.ianker.com/product/68UNHUB-B7U The hub works great and I never have a problem with anything else. I've been charging my phones and tablets with it forever, and I have my webcam, mouse, and keyboard plugged into it. Everything works fine until I plug the rumba board in.