Hasselblad 500EL/M trying to get the lens on.

[jedelvalle]

I, I have a Hasselblad 500EL/M that I purchased over the internet. I purchased the film back and the lens separate to other sellers and when I put the battery adapter for the CD-P2 battery, the electric motor engages but never stops.
I do have the film back, but I put a film in it and I'm afraid that if I put it, it will ruin the film.