SL66 12/24 Back Issue

I have the 12/24 back on my Sl66 and have recently started shooting the camera again. I've been shooting 220 film and set the switch to the "24"position. Twice now it has slipped to the "12" position and the button pops up and the roll ends. Can I just tape it to the correct position or does it need repair?

thanks

IT

I have been shooting with the old backs for years and never had this problem.
Try to tape it at first, if that does not work it has te be repaired.
Be shure you set the switch before closing the back.

Peter