recent RB67 Pro S with lenses

[Mark Cowart]

I'm new to MF and was just given an RB67 Pro S with prism finder, a couple of 120 backs and a 220 back. I discovered the following issues when testing the camera and lenses. My question is, could I be doing something wrong instead of the issues I'm having be issues that need to be fixed. I sent an email to Bill at mamyiarepair and am waiting for a reply. Here is the list of what I have found so far:

I have found the following problems testing the camera and lenses.

1. The shutter cocking lever has some resistance / drag about at about 75% down.
   
2. There are times when it will cock but the rear baffle and mirror do not drop and the shutter release does not function. I cock it a second time and the baffle and mirror drop and shutter release does work.

I have tested the lenses with the back off the camera. For lenses I have found the following:

1. 50mm Sekor C f4.5 does not line-up with the large dot on the body. I'm not sure if it will affect the image. Otherwise it seems to function properly.
   
2. 90mm Sekor C f3.8 shutter only operates if I remove the lens and manually cock the lens. I cock the lens, mount it on the camera, and the shutter and aperture only seem to work that time. If I take the lens off after cocking the camera remounting the lens seems to fire the shutter because when I cock the camera the shutter does not function. If I remove the lens before cocking the camera, manually cock the lens, remount lens and then cock the camera, the shutter and aperture function that one time.
3. 150mm Sekor SF C f4 the shutter does not seem to work. It sounds like the aperture is working. the process for getting the shutter to work like the 90mm did not work.
4. 127 Sekor f3.8 Shutter on lens seems to function normally but about every other time I cock the camera it will open the shutter and aperture as if I pressed the shutter release even though I did not. Every few times, the shutter will not function - will not depress - after cocking the camera. I take off the lens, manually cock the lens, remount lens, and then press shutter release. While attempting to repeat this last step, the shutter does not close at all but I am able to cock the camera and activate the shutter.
5. 180mm Sekor C f4.5 shutter does not function. I hear a clicking sound - might be the aperture closing.
6. 250mm Sekor f4.5 shutter functioned only the first time I mounted lens on camera after manually cocking the lens.

The R-Lock and G-Lock light seals on the Pro S revolving adapter need to be replaced.

As I said, MF and Mamiya are new to me so I want to be sure I'm not doing something wrong. I have the manual in front of me and I've watched a few videos on youtube.

 

[cramej]

#1 - Do not mount a lens with an uncocked shutter. It can get stuck and is difficult to remove. Damage can occur if you attempt to cock the body with the lens uncocked.

It sounds like the body is not moving the cocking mechanism far enough to cock the lens.

You can test the shutters off the body by depressing the little pin near one of the shutter cocking posts and then rotating the posts. You will see the aperture close as you move them, then the shutter will fire (hopefully ).

 

[MattKing]

Welcome to Photrio.
The behavior of the cocking lever is consistent with what happens if there is something impeding its travel. I used to find that that would happen if the neck strap got in the way.
It may simply require making sure that you move that lever completely through its travel - at different positions the resistance is different, as the system performs different parts of its functions. The problem might be due to no more than the camera and lenses needing to have various functions cleaned and lubricated.

 

[shutterfinger]

Service manuals that may come in handy.
Lens shutters https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Lenses-Service.pdf
Pro S service instructions https://learncamerarepair.com/downloads/pdf/mamiya-rb67-pro-s-repair-manual.pdf
Pro & Pro S parts https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Pro-S-Parts-Catalog.pdf

PDF pages 1 - 5 of the service manual gives trouble and probable cause of the failure, a worthwhile read.
PDF page 13 of the service manual shows the cocking lever, shafts and gears involved in operating the cocking lever.
PDF page 11 shows how to check position of the cocking ring.

Lens problems 1 & 2 suggest the body is not cocking the shutter properly.
Lens problem 3 & 5 dead shutter, may not be repairable, #6 sticking levers in the shutter.
All shutters need a full Clean, Lube, Adjust.

 

[Mark Cowart]

#1 - Do not mount a lens with an uncocked shutter. It can get stuck and is difficult to remove. Damage can occur if you attempt to cock the body with the lens uncocked.

It sounds like the body is not moving the cocking mechanism far enough to cock the lens.

You can test the shutters off the body by depressing the little pin near one of the shutter cocking posts and then rotating the posts. You will see the aperture close as you move them, then the shutter will fire (hopefully ).

Thank you - that was helpful

 

[Mark Cowart]

Welcome to Photrio.
The behavior of the cocking lever is consistent with what happens if there is something impeding its travel. I used to find that that would happen if the neck strap got in the way.
It may simply require making sure that you move that lever completely through its travel - at different positions the resistance is different, as the system performs different parts of its functions. The problem might be due to no more than the camera and lenses needing to have various functions cleaned and lubricated.

Thank you

I sent the camera to Mamiyarepair after talking through my issues with Bill.

looking forward to getting the camera back and taking some pictures.

I also talked to Jon Goodman and will order his light seal kit.

mark

 

[Mark Cowart]

Service manuals that may come in handy.
Lens shutters https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Lenses-Service.pdf
Pro S service instructions https://learncamerarepair.com/downloads/pdf/mamiya-rb67-pro-s-repair-manual.pdf
Pro & Pro S parts https://learncamerarepair.com/downloads/pdf/Mamiya-RB67-Pro-S-Parts-Catalog.pdf

PDF pages 1 - 5 of the service manual gives trouble and probable cause of the failure, a worthwhile read.
PDF page 13 of the service manual shows the cocking lever, shafts and gears involved in operating the cocking lever.
PDF page 11 shows how to check position of the cocking ring.

Lens problems 1 & 2 suggest the body is not cocking the shutter properly.
Lens problem 3 & 5 dead shutter, may not be repairable, #6 sticking levers in the shutter.
All shutters need a full Clean, Lube, Adjust.

These will help a lot.
Thank you