I have just gotten my recently purchased Polaroid SX-70 Sonar Autofocus. Unfortunately it does not work properly.

The viewfinder stays black. I tried all sorts of tips I find on the internet. Inserting a film pack to let it 'recycle' does not seem to work. There are also some topics about the motor shaft being broken. Mine does work and eject film properly, only it seems to take a long while. You can clearly hear something pop up or down, and then you have to wait about 10/15 seconds before the film is ejected.

Because I don't want to rip it open at once, maybe someone has an idea? I have made a video so you can see what is going on.

http://www.youtube.com/watch?v=iMEb37pac8c