What's wrong!?? Please help!

[fmw]

Time to CLA the camera, I'm afraid.

 

[W.Smith]

It's not a certainty that this has fixed the problem but I really don't see why it shouldn't have

.
So the jury's still out on this one, isn't it? We won't know if it indeed was that seal until Stingray has tried it out.
Because I still think there's a lot to MysteryScribe's and JamesD's suggestion that it is a hanging shutter. The neg strip has got all the hallmarks of it.

 

[Jeff Canes]

I've had AE-1P(s) too the hanging shutter seem like a good guess