Thanks for your quick replies. I had mirror and shutter controlled in a analog camerashop no problems there. Of course they test them without the lens on. Sometimes parts of the picture are not lighted that must be a shutter problem.But the brackets go on on the unlighted areas between the negatives. And the mirror folds up and away from the film, reflection seems difficult.
Light leak. Check the foam.
Still doesn't explain frame #1 though.