RB67 6x8 Pro-S Motorized film back not winding.

Hi, I'm new here this is my second roll shooting this camera. The first roll was working without a problem but on the first exposure of my second roll the motorized back just won't advance automatically to the next frame.

A little more info, I shot the first exposure on mirror up mode and I set the selector knob to M.UP and multi exposure lever to normal. It will not wind and I have to wind it manually. Afterwards I took a second exposure with both selector knob and multiple exposure lever to normal and still it will not wind automatically.

Motorized back is already switched on and battery check is all good so I don't know where did I go wrong :/

The RB manual backs depend on a pin popping out from the body to signal the back to advance. There's one in the upper left(for horizontal upper right for vertical)
corner of the back adapter(with silver collar) Without the back put a finger gently on it & trip the body. It may be possible to feel it momentarily hit your finger. If it
doesn't try a drop of Naptha to see if it frees up. DO NOT USE OIL/WD40!

It's a shot in the dark but won't hurt anything.

Camera battery check are unreliable. They tell you there is a battery with some charge in it in the camera. They do not tell you the battery has enough charge to operate the camera.
This manual http://www.cameramanuals.org/mamiya_pdf/mamiya_rb67_motor_drive.pdf says the back uses 6 AA batteries. New AA batteries read 1.56V when new on a volt meter. AA batteries that read 1.5V on a volt meter will drop to 1.46V or 1.47V when under load from the camera in operation and will not correctly power the camera. AA batteries that read 1.5V or less on a volt meter need replacing.

Also check that the film is loaded correctly.

shutterfinger said:

Camera battery check are unreliable. They tell you there is a battery with some charge in it in the camera. They do not tell you the battery has enough charge to operate the camera.
This manual http://www.cameramanuals.org/mamiya_pdf/mamiya_rb67_motor_drive.pdf says the back uses 6 AA batteries. New AA batteries read 1.56V when new on a volt meter. AA batteries that read 1.5V on a volt meter will drop to 1.46V or 1.47V when under load from the camera in operation and will not correctly power the camera. AA batteries that read 1.5V or less on a volt meter need replacing.

Also check that the film is loaded correctly.

Click to expand...

I think the problem here is the battery contacts or the battery itself, I managed to shoot through the entire roll and sometimes the back works. Atleast the problem is now known, thank you

Download the RB67 ProS service manual here: https://www.manualslib.com/manual/1015573/Mamiya-Rb-67-Pro-S.html
it does not cover the motorized back but does cover the standard back.
The motorized back operating instructions are available here: http://mamiya.org/content/RB_6x8_Power_back.pdf
Cleaning battery corrosion from electronics: https://cleaning.lovetoknow.com/How_to_Clean_Leaking_AA_Batteries
Burnish contacts with a pencil or pen eraser or a contact cleaning pen if they are not shinny.