I'm not claiming to be an expert on scanner mechanics and electronics, but to me this looks like it could come from several sources. From a strictly mechanical basic, it could be something very wrong with the mechanism that moves the film carrier, causing it to be shifted from slide to side as it worms it way through the travel. I can't recall anymore which scanners Nikon made that had the film and carrier move and which had the whole image capture stage move, so whichever one moves in this scanner, it might be sliding around.
However, this could also be am electronic problem with timing shifting between the capture and the digital conversion, slowly shifting the pixels over one direction until it meets a tolerance or check point, and then shifting the other way. Obviously, this guy will claim it was "fine when it left here" and must have happened during shipping or at while in your possession, or maybe he forgot to lock the scanner's head for shipment and something got knocked out of whack. I hope you get a good warranty on the repair, because I would be quite wary of this guy's work. I would only give him one more chance to correct it, and to provide an extended warranty on his work. If it comes back bad again, I would contact Nikon. Art ---------------------------------------------------------------------------------------- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body