[HELP] Mamiya RB67 motorized back problem

nolan · Nov 13, 2017

Morning all!

Hoping someone can please assist me.

I recently purchased a RB67 motorized back. Yesterday I took it out for a test. Film loaded, look my first frame and all seemed ok... until I took my second frame. I noticed the counter was on 5. Tried another frame and then the film automatically rewinded. After taking the film out I double checked the back to see if everything was set correctly and it was. Selector and multiple exposure selector were both on the white square. Batteries are fresh.

Anyone had this issue before and how can I fix it?

Thanks for your time!!

Neil Grant · Nov 13, 2017

...sounds like this film is no use to you anymore. Try respooling and then reloading it as a test. It should wind to the first frame and stop.

nolan · Nov 13, 2017

Neil Grant said:
...sounds like this film is no use to you anymore. Try respooling and then reloading it as a test. It should wind to the first frame and stop.

Thank you Neil!

I'll definitely give it a go again.
When I first loaded it, it worked perfectly... after the first frame it went pear-shaped...

Neil Grant · Nov 14, 2017

120 or 220 selected?

nolan · Nov 14, 2017

Neil Grant said:
120 or 220 selected?

120 selected.

I was thinking... I loaded the back when it was on the camera. In the manual it says load first then attach to the camera...
Could this have been what caused the issue maybe?

Neil Grant · Nov 14, 2017

...i don't think it makes a difference whether the back is attached to the camera or not when loading. Sounds lke the back isn't 'feeling' the frame spacing correctly. I believe there's a toothed wheel that senses how much film has passed. You can continue to test the back by respooling your spoiled film.

nolan · Nov 14, 2017

Thank you Neil!

I'll keep on testing it.

Really appreciate your help!

nolan · Nov 15, 2017

Hi Neil!

Did some more testing last night. Loaded the film, got it to frame #1 without issues. Cocked the camera, fired it and the film advanced right up until the end of the spool this time. It has gotten worse! I have sent pics and videos to the place I bought it from. Hoping they can assist too.

Thanks again for all the assistance!

Meerkieker · Nov 15, 2017

Hello,

I've had (and still have to some degree) the exact same issue with the motorized back. After an unpredictable amount of shots the back used to advance the film up to the end of the spool with that click sounds that repeats itself at every frame.

In my case i had to screw tighter the chrome plates which lock the back to the body, the point is that before doing that, the pins were far enough from the back to compromise the communication between the two parts. Briefly said, the film back couldn't feel that the shutter has been shut. I still have this issue to a certain degree for another reason, my body needs a CLA, as the pins sometimes get stuck in advancing position.

here you have a link to my thread: https://www.photrio.com/forum/threads/help-mamiya-rb67-coupling-arm-issue.146893/

WilmarcoImaging · Nov 15, 2017

Agree with meerkieker that it sounds like a back-to-body communication issue. In the case with my Pro S body, I believe there is something worn or out of adjustment in the coupling arm system that tells the back that the body has fired. It requires opening the left side of the camera, opposite the cocking lever. I have not done this as I have a Pro SD body, but would like to repair it some day. I have tried adjusting the tightness of the revolving adapter pins, plates and screws but in my case it does not improve the situation. I think the repair work is needed inside the body.

To summarize, this problem can be related to the body and the revolving adapter, and not the film back.

Sirius Glass · Nov 15, 2017

Sounds like it needs a CLA.

nolan · Nov 16, 2017

Thank you Meerkieker, WilmarcoImaging and Sirius Glass!! I'll definitely look at the coupling arm system as well as tightening the screws. Maybe it is also time for another CLA.

Once this issue has been resolved, I'll report back.

Thanks again!!

Neil Grant · Nov 16, 2017

...i have one of these powerdrive backs too (6x8) - so it's really useful to hear about trouble-shooting with them.

ryushinkan · Nov 16, 2017

nolan said:
Morning all!

Hoping someone can please assist me.

I recently purchased a RB67 motorized back. Yesterday I took it out for a test. Film loaded, look my first frame and all seemed ok... until I took my second frame. I noticed the counter was on 5. Tried another frame and then the film automatically rewinded. After taking the film out I double checked the back to see if everything was set correctly and it was. Selector and multiple exposure selector were both on the white square. Batteries are fresh.

Anyone had this issue before and how can I fix it?

Thanks for your time!!

Take a look here... https://rb67.helluin.org/?s=power+backs great resource

[HELP] Mamiya RB67 motorized back problem

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