I had everything hooked up and ready to test, I flipped the power switch on the RosBot, all went well and it turned on. Next I went to plug in the USB cord and connect the printer to my computer in order to load the firmware and commence with the testing. As soon as I plugged the cord into the Mega, befor eit was all the way in the Mega started smoking and caught fire right to the left of the USB port if you are looking straight into the port. It was the little protection component next to the USB, burned a hole straight through the board! 

I assumed it must have been a factory defect of some sort and promptly contacted the supplier, told them the story and had a replacement on its way the next day. When I received the second Mega, I hooked everything up, plugged in the USB before turning on the power, all was well, no smoke! OK, I said, and flipped the power switch...... MAN NOT AGAIN!!! Yep it toasted the second board! I contacted the supplier and luckily they were nice enough to send a 2nd replacement! I couldnt afford to buy another Mega 2560, I already spent my budget.

More to come.....