window will not close (not the old doozy)

[mo]

Hi, looking for some help with what appears to be an uncommon power window problem. Its not the cable holder widget thingy which is fine.
The window gets stuck at less than half way up. Its goes up and down, albeit with an unhealthy sound, but will not go any further. A loud pop preceeded the failure. When it goes down, it sounds like it goes too far and I get some loud knocking noises before the motor stops.

I have the door panel off and can not see anything obviously broken. The passenger side is Ok.

Any advice please?

Thank

Mo