Mamiya RB67 Pro S - Frame counter won't advance

[Jakub Dabrowski]

Hi, I put in my first roll of film correctly and made sure that the double exposure lever was turned off. Then I tried to advanced the film onto the first frame however it stayed on S with the red indicator, all whilst advancing the film inside. I opened the back and unspooled the film and tried again - same thing happened. I noticed that there is a screw missing in the bottom left of the film holder but I'm unsure if this is the issue or if something else is causing the problem. Could someone please help?

 

[shutterfinger]

Download the Service Manual for the RB67 Pro S here: https://www.manualagent.com/mamiya/rb67-pro-s/repair-manual (click on the small download button under page 1)
The roll film holder instructions start on manual page 39 PDF page 48. Section 14, Film wind-stop mechanism is your problem area. Release lever 10 is likely stuck in the release position.
Use minimal disassembly, flush with 90% Isopropyl Alcohol, apply a straight pin point drop of light clock/machine oil to the pivot(s) of the gears. A trace of light weight grease (white lithium) on the gear teeth will help make it smoother.