Pots … no, not that kinda Pot.

So, got the mechanical parts working on the Yashica Mat-124G … now to figure out how to adjust the light meter.

This camera has a CdS light meter which requires a battery, unlike the burnt out selenium light meters that many older cameras started out with. Sometimes these meters is just not right anymore and require adjustment … sometimes they just don’t do nothing.

A basic circuit consists of a CdS photoresistor, a resistor/potentiometer, power source, and a galvanometer … so how hard could it be to adjust … the Yashica Mat-124G appears to have two potentiometers … hmm.

The first thing to do is to remove the hood. On the left side of the body is a lever that turns the light meter circuit on and off as the hood is opened/closed. The big round thing in the back of the light meter is the galvanometer. To the left of it are the two potentiometers. There are two arms that are coupled to the shutter speed and aperture dial. The speed arm rotates the galvanometer, while the aperture arm moves the aperture target (the yellow arm).

One thing that I did find was that the galvanometer has a cap that the aperture target is attached to. The target arm is pushed as the aperture dial is moved. The seal that was holding the cap in place was broken, so the cap was not in its correct position (looks likes one of the previous owners had dislodged this and also bend the galvanometer arm) … I figured out that the aperture should be set wide open before repositioning the cap.

Trial and error … playing around with all the parts I got the meter to read almost accurately. I still have to figure out the best position of the potentiometers to get some accuracy in low and bright lighting conditions.

… and I say again, thanks to Rick Oleson’s handy dandy CD of tips and for sharing his vast amount of knowledge -> http://rick_oleson.tripod.com … and also Hans Kerensky -> https://www.flickr.com/photos/29504544@N08/albums

** this is an old post, but I thought I should update it with this discussion link from the Photrio forum about these pots

Yashica Mat-124 G … winder side, not side-winder.

This camera has a problem with setting the shutter. A complete wind does not set it, so you can never take a picture … hmm, sounds like something is not coupling correctly.

The first thing you have to do … and you already know this … is to remove the leatherette. Take off the one back/strap holder arm before removing. With the one that I have here it was fairly easy to peel the leatherette off without damaging it. Take your time.

Push out the winding arm pin. Remove the arm and the four items that go with it.

Now you can unscrew the plate.

The rotary disc for the winding arm it attached with a circular nut.

Note the position of the golden arm.

Unscrew it and remove the stuff underneath it.

Remove the spring from the counter reverse lever (right), remove screw and take out arm.

Remove the 12/24 exp indicator plate, first pull off the two springs.

Pull out the silver gear.

The counter change gear arm (bottom) is the next to go.

The counter dial has a spring loaded screw in the middle. Take that off with the dial and the dial plate underneath it.

The counter reverse lever (top) is held on by one screw on the right. Slightly lift the arm on the left to pop it off for removal.

One screw holds the winding stopper arm (centre) , and you should release one arm of the spring.

The middle golden gear (bottom) has one pin screw in the middle that is unscrewed clockwise … very important.

Now you can remove the winding assembly by taking out the four screws.

Now you can see the shutter cocking arm … and in my case it is bent upwards. This means that it will never push down to its full distance.

You can try to rebend it back into shape.

If you want to take that part out you will need to remove the front lens/shutter component.

Here is my bad attempt at bending the arm down … which actually caused more metal fatigue, so when I put it back in it bent itself out of shape again.

Note: on the back side of this part is a riveted switch that prevents double exposures … do not damage this part, as it will cause a lot of headaches. If this part does not freely move, the winder will be in a locked position after the shutter is released. I am guessing this is why some people force the winder and bend the arm.

As I mentioned before, the Yashica Mat-EM has the exact same part (just not golden) so you can just replace it.

When putting back together you should be very careful that the arm is positioned above the shutter release mechanism.

You will also need to reload the spring on the counter dial. If the counter dial is not spinning freely, then loosing the screw and move the dial around so it sits properly.

… and be aware of the little springs that are all over the place.

Yashica … MAT-124G … flaw ?

Out of all the TLR’s out there, I’ve noticed that the Yashica MAT-124G is one of the most sought after cameras … even more than the Rollei because it is more affordable (hmm, actually all TLR’s are more affordable than Rollei’s).

The G, is the moderized/improved version of the plain old 124/12/24. The G refers to the addition of gold contacts in the meter. Some parts were changed from metal to plastic, and the chrome is covered in black paint … to make it a darker camera. In terms of IQ, it has the same optical components as the other models … so don’t think the G is the best Yashica TLR in that respect, especially when the price of the G can be much higher.

You can read more at the  yashicatlr.com site.

In my repair of this camera I came upon a subject that has been mentioned on the web before … incomplete shutter cocking. After taking it apart and doing a lot of mental battles about how the mechanisms work/interact, I came to the “personal” conclusion that there is a design flaw with the newer winding mechanism.

The shutter cocking plate has an elbow that is pushed down by another arm that is connected to the winder cam plate. As the cam plate rotates it pushes/pulls the shutter cocking arm … this arm pushes down to rotate the shutter cocking plate. The problem I have with the design is how high the elbow sits … it seems to me that they placed it too high … and since the shutter cocking plate moves in a circular motion and the shutter cocking arm moves in a linear motion it (the arm) requires most of its force when starting the movement from its highest position.

Now this all works fine when the camera parts are all in original condition, but I think after some time the arm has a greater chance to become stressed (typically when some users unfamiliar with the camera, force the winder when they shouldn’t). Once the arm is bent it will no longer be able to obtain the full motion to complete the shutter cocking … and it does not take much deviance in the arm … and once the metal gets fatigued it will continue to bend out of shape easier … and even after it is straightened (as the straightening process placed additional fatigue on it) it will continue to do so.

The image (in my repair post) shows my sad attempt at straightening the arm … it’s riveted in place which made it not so easy.

Now … to the good news. I made a guess … yes I still have brain cells that can do that … based on the number of Yashica TLR’s I’ve taken apart, the parts appear to be the same. The Yashica-mat EM that I just repaired (and nobody wanted to buy) now became a parts camera … and my guess is right, same part. I think the E, LM, EM, 12, 24, and 124(G) share most the same mechanical parts.

OK, some more TLR’s

Soooo, I have collected some more TLR’s. In hunting for some broken cameras I came across a Yashica Mat 124G, and it happened to be accompanied by a broken baby … the Yashica-44.

The Seller was kind enough to throw in another 4×4 TLR that was also not working and also a TLR pencil sharpener.

As you can see the 124G has got some alien finder hood attached to it.

The Yashica-44 was modified for 35mm film so it is missing a roller.

With the exception of the pencil sharpener, all three cameras have some sort of problem with shutter release or stuck winder.

My latest victims …

The Yashica-MAT EM had been sitting on my workbench for the past two years … finally got assembled today. It came to me in rough shape, the focus knob was almost falling off, the winder was stuck, the shutter was jammed, broken screws, etc.

The only thing I could not fix was a glitch in the winder release mechanism … sometimes after winding the crank it will not complete, so you have to press the shutter button again to engage the winder release. Also I could not get into the light meter because all the screws were jammed. I don’t think I will continue to restore it with new leatherette, as I have grown weary of it.

The Canon IV sb with lens, was rusting all over … and I took the chance on buying it on the hopes the lens did not have haze/fungus.

The Canon IV sb and the Canon Serenar 50mm f/1.8 were a lot easier to handle. The IV sb needed a cleaning and removal of the top plate. Rusted/seized screws prevented me from going further, so I could not check the shutter for leaks.

The lens was completely disassembled and cleaned. The lens did not end up with any haze or fungus … but I did discover some decementing of the rear elements starting to occur.

 

The family of Yashica TLRs and Canon Barnack type rangefinders are all very similar in design, so if you have worked with one model the rest are almost the same … including lenses and shutters.

Well, my fixer upping will be going to slow down for a bit as it is becoming economically more difficult to get cameras … I will keep hunting for BB (broken bargains.)