And the first unit had the same problem? We don't get problems from these units, and it seems you likely you may have returned a perfectly functioning unit. I am glad you posted, as it underlines a point I made the other day about a number of units returned for repair are working and why we offer the only 30 days on the return policy.
The problem is pretty clear, I imagine to many of our MIG guys, but here's the problem.
You don't have your Power cable (hanging loose) plugged into the front Positive port. This is where the unit picks up its power... If you look at the very inside picture you posted of the wire feeder, you'll see the power input cable attached to the lug on the backside of the connector and it hangs out the front. There's your problem right there.