My board programmed OK using Arduino software and spoke back to me on the USB port. I then installed it in the system. The display worked fine selecting menu items when powered up. However, when I plugged the USB connector in, it all went dead. When I disconnected everything and connected up to the Arduino software, it spoke to me again. Now if I connect it up to the power supply, with only other connection the display (Smart Controller), it seems OK, but display goes blank when I connect the USB. Any ideas?