Window regulator button roller?
 

1970 914. Cranking drivers side window up, works great. Cranking down? Regulator cranks smoothly but window does not move. I have to push the window down. Then it rolls up fine. Sound like the regulator button roller? If so would it not also have trouble cranking back up? Would like some feedback from anyone who has had this issue before I tear the door apart.

The early window mechanism is cable operated. Turning the crank pushes or pulls a cable which moves the window. The window may have come away from the support on the cable, or there could be something else going on. I suggest removing the inner door panel ("door card") and inspecting the mechanism to see what's borked.

--DD

Definitely remove the panel and have a look. Should be obvious at that point what is wrong.