HM2 and dead ac/dc adapter

You're right, I think I stupidly took a battery from my bass with active pickups, assuming it had enough "juice" left. Turns out when I measure the battery it gives 4v...
So I'll try a new battery tomorrow. If that was the only problem I'll have to apologize for wasting your time, although that did push me to research and learn stuff.

But I suspect there's more than the battery thing...