2 of my 3 Avatars were like that. One has been repaired, the other is at the shop. I don't remember what the problem was exactly but my tech was able to fix it. Here is the email form my tech for the one he's working on right now:
09/02/09 VERIFIED COMPLAINT. DIAGNOSED UNIT TO HAVE FAILED
COMPONENTS AND CONNECTIONS IN POWER SUPPLY. UNIT ALSO HAS A
FAILED MAIN OUTPUT LED. UNIT'S ATTACK SLIDER IS BROKEN.
SUBMIT EST OF $210 FOR REPAIR. ATTACK SLIDER IS NO LONGER
Standard audio cables are all you need to interface the CV/GATE. The Avatar uses mini plugs and (I think) the BassStation uses phone plugs, so you will need the appropriate connectors on your cables.