I have a 21' Dometic 9100 Power Awning. Yesterday, as we were setting up- I was putting the support poles under each end. I did the motor end first (facing the camper, right side) and started doing the spring end (left side).
As I was tightening the ratchet strap on the left-side, my son was hanging from the tail end of the ratchet strap on the right-side. I don't know which caused the issue, but we heard a bit of pop/bang and the awning extended itself slightly.
Now, when the switch is pressed- I can hear the motor engage and turn but the awning tube doesn't do anything more than lurch for the tiniest/briefest of moments.
When I removed the awning arm from the awning tube and turn the housing for the motor (like you would to unwind the torsion spring), I basically don't feel any resistance.
At this point, I think I need to (but am hesitant to) drill out the pop-rivets on the cap and start diagnosing this from the inside.
I have a video of the symptoms:
I also have various pictures, but I'm not sure what any will show beyond what the video shows.