I just got mine ordered off eBay too and i'm having difficulties. I was able to get and correctly install the right drivers, but still haven't gotten it to work. I see the command line going around has helped a lot of people... I hate to ask a total n00b question here, but how and where do I go about entering that command information in CGminer? I'm not too families with theses things yet, but I've been learning a ton lately and have been controlling my other usb miner with BFGminer on Slush. Any help greatly appreciated here.
Bitmain's cgminer can be downloaded here
https://bitmaintech.com/files/download/cgminer-run-windows-20141027.rar it is the only mining program that supports U3 at the moment. Once you extract the cgminer, make TEXT FILE in that folder and rename it cgminer.bat then right click on it and choose edit. then copy and paste this command line there (cgminer.exe --bmsc-options 115200:0.65 -o POOL:PORT -u USER -p PASS --bmsc-voltage 0800 --bmsc-freq 1306)
Ofcourse change the POOL to your mining pool PORT to the pool port USER to your username in that pool and PASS to the password. Start cgminer from the newly created cgminer.bat file. It will run the command and start mining.
Let me know if that helped