Mamiya Press Rangefinder Mechanism Sticks

[absalom1951]

I recently picked up a Mamiya Press Super 23 with a film back and lens . It was not known if camera , back , or lens worked. I got it so I could try to clean the viewfinder on it , before I attempted to clean my user Super 23. The lens is trash , it has so much haze that you can barely see through it, shutter works fine. The 6x7 film back seems to work fine, only needs new light seals- it alone is worth what I paid for the whole setup.

I successively cleaned the viewfinder where there is very noticeable improvement . Before it was cleaned the rangefinder was very dim and cloudy. Now, Its a lot better than my user 23. But sometimes the rangefinder mechanism sticks and won't focus properly. Is there a lubricant that I dare use to put a drop or two into the rangefinder mechanism ?

If I can fix this rangefinder sticky situation I will have another Super 23

 

[Carter john]

I had something similar, mine would lag. I would put it quickly to infinity and it would take 10 seconds to return. I just kept working it until it was loose. It has been fine for 6-7 years.

 

[absalom1951]

People and cameras have that in common- sometimes exercise is the best solution.

thanks for the reply

 

[shutterfinger]

My experience is with side rangefinders on press cameras.
Disassemble the rangefinder mechanism, clean the parts in degreaser, apply a trace amount of white lithium grease or similar to surfaces sliding against one another and a trace of oil to the pivots such as clock oil or TriFlow.
It will continue to be a PITA ever few weeks or months until you do.

 

[absalom1951]

Disassembling this rangefinder is way beyond my skill set. It has way to many pieces. I will follow your suggestion of a trace of oil to the pivots.

thanks for the reply

 

[shutterfinger]

Get a can of CRC QuickDry Electronic Contact Cleaner https://www.homedepot.com/p/CRC-11-oz-QD-Electronic-Cleaner-05103/205021975 and flush out the mechanism as best you can before adding any new lubrication.
A trace of oil or grease is so light that one needs high magnification to see it or a very bright light at an angle to the surface.
TriFlow https://www.amazon.com/Tri-Flow-Sup...5&sr=8-11&keywords=triflow+superior+lubricant

 

[absalom1951]

Those are 2 items that everyone should have in their arsenal. Weather and wife permitting I will pickup both in the next couple of days.

Your info greatly appreciated

 

[gordrob]

You may want to check out this site as it has some information on the Mamiya rangefinder for adjustment calibration and some cleaning tips
https://www.photo.net/discuss/threads/calibrating-range-finder-in-mamiya-press-universal.12328/
Gord

 

[absalom1951]

Gord - Some good information there, I saved the thread for reference which I'm sure I will need.

thanks - tom

 

[Daire Quinlan]

That thread is partly wrong though (along with a bunch of other similar advice on various forum threads). What's described as an 'infinity adjustment' on many of those threads is just an infinity stop for the rangefinder. It has no effect other than to stop the rangefinder from moving. The two adjustments are the main distance adjustment, and an eccentric screw that adjusts the travel of the rangefinder over the range.
I describe it here https://www.flickr.com/groups/18528883@N00/discuss/72157640597185714/

The main adjustment screw adjusts the entire mechanism , that 45 degree is just an infinity stop though, it adjusts nothing. There's another eccentric screw in the mechanism that adjusts the relative travel of the rangefinder over the range.

I had a repair manual for the Polaroid 600SE which uses the same mechanism, and it details the correct procedure. Namely, you adjust the main adjustment screw so that the image is correctly focused at infinity, then, if neccessary, adjust the eccentric screw until the image is adjusted correctly up close.

www.everythingretek.com/PRDLibrary/LIBRARY8/LIBRARY/REPAI...

Page 87 onward, from "Near Distance Tracking Test"

Note that the eccentric screw, in "Figure 5-21. RF/VF near-distance eccentric screw adjustment" is NOT the 45 degree screw that everyone talks about when they talk about near distance adjustment, that screw is just a plain stop.

I got mine to fairly good degree of accuracy, it's off at the near and the far ends by less than is noticeable at about f/5.6 or so.

 

[absalom1951]

Hello Daire,
That info will save me some frustrating moments. I'm sure sooner or later I will need to adjust the rangefinder. As complicated as the rangefinder is I'm amazed at how rugged they are built to be able to still be functioning for 50 some years. How many digital cameras will be working after 50 years of use ?

thanks - om

 

[absalom1951]

thanks - om[/QUOTE]

Get a can of CRC QuickDry Electronic Contact Cleaner https://www.homedepot.com/p/CRC-11-oz-QD-Electronic-Cleaner-05103/205021975 and flush out the mechanism as best you can before adding any new lubrication.
A trace of oil or grease is so light that one needs high magnification to see it or a very bright light at an angle to the surface.
TriFlow https://www.amazon.com/Tri-Flow-Sup...5&sr=8-11&keywords=triflow+superior+lubricant

Flushed out and oiled the rangefinder mechanism-- works great

Rangefinder was just a hair off so figure I would just as well try adjusting it. Got it down snuff thanks to advice given by Daire and Gord ..

thanks a lot guys !!