Mamiya RB67 motorized back not advancing back to "1" when the roll is finished

[CaleRB67]

As the title mentions, it's stuck on then20th exposure number and thinks it needs to re-wind the film every time I place the (now ruined) roll in. Yet stays on 20 and doesn't go back to 1 when I replace it.

 

[Neil Grant]

...i don't really understand: 'needs to rewind the film' - roll film isn't rewound, it only goes forwards through the camera to the take up spool. Do yo have 220 film in the magazine?

 

[CaleRB67]

When the roll is completed, the numbers should go back to “0” or start a new roll when placed in. Though my number is stuck on “20” so every time I place a roll in, my motorised backing automatically tells the backing to wind up the spook and doesn’t restart back to “o”

 

[mpirie]

Are the motorised backs like the mechanical ones where a spring loaded latch is engaged when the back is closed to start the film advance mechanism?

Once the back is opened to remove the film, the spring catch releases and the counter returns to zero.

Maybe the catch is jammed on your back, stopping the reset?

Mike