Yashica FX3 shutter running too fast

Renzo35mm · Jan 29, 2025

I'm trying to adjust the shutter speeds of this FX-3 but I can't get the shutter to fire at the correct speeds. I managed to get it right using the adjustment spring for low speeds right below the black gear but the shutter doesn't work with speeds of 1/1, 1/2 and 1/4 s because the spring tension is too low. Putting more tension in the spring leads to a constant underexposing of 1 stop in all speeds.

The shutter has been cleaned with a solvent wash. Lubrification of the mechanism doesn't seemed to solve the problem

Does anyone have experience working with this shutter? It's practically the same shutter used in the Nikon FM2

ic-racer · Jan 29, 2025

How are you measuring the shutter speed? Are your curtain travel times OK. Should be about 5ms.

If everything else all checks out then, indeed, "...such defect as a second being over and 1/125 being under cannot be repaired. FX-3 Service manual"

Renzo35mm · Jan 29, 2025

ic-racer said:
How are you measuring the shutter speed? Are your curtain travel times OK. Should be about 5ms.

If everything else all checks out then, indeed, "...such defect as a second being over and 1/125 being under cannot be repaired. FX-3 Service manual"

I'm using my phone camera that can record a video of 240 fps. Then I go frame by frame to measure the exposure time. It's fine for speeds up to 1/250s.

Last time I checked the curtain time travel was about 3 ms. But I couldn't find any information about a specific value in the repair manual.

Anyway, I noticed that the I forgot to oil the pivot point of the slow escapement gears. After that speeds seemed to have lowered. 1/30 now reads 1/40 instead of 1/60. Going to do a few more tests.

monopix · Jan 30, 2025

I've worked on a lot of those but I've never seen what you're describing. They're normally pretty solid. I would question what's caused it to be wrong. Has it (or the camera) been exposed to excessive wet or been stored badly? I've never known the slow speeds to not work. The shutters don't usually need lubricating. This might help https://contax139.blogspot.com/2025/01/contax-s2-shutter-adjustment.html

Renzo35mm · Jan 30, 2025

monopix said:
I've worked on a lot of those but I've never seen what you're describing. They're normally pretty solid. I would question what's caused it to be wrong. Has it (or the camera) been exposed to excessive wet or been stored badly? I've never known the slow speeds to not work. The shutters don't usually need lubricating. This might help https://contax139.blogspot.com/2025/01/contax-s2-shutter-adjustment.html

Thanks, I was using that same guide to lead me. The shutter looked fine and with no sign of corrosion or tampering. Before I started measuring the speeds I disassembled the blades and soaked the whole mechanism in solvent . It seemed that lubricating the gears and setting the spring to a very slow tension solved the problem. I still need to adjust the 1/500 and 1/1000 speeds as they seem to read at least a full stop too slow.

monopix · Jan 30, 2025

Renzo35mm said:
Thanks, I was using that same guide to lead me. The shutter looked fine and with no sign of corrosion or tampering. Before I started measuring the speeds I disassembled the blades and soaked the whole mechanism in solvent . It seemed that lubricating the gears and setting the spring to a very slow tension solved the problem. I still need to adjust the 1/500 and 1/1000 speeds as they seem to read at least a full stop too slow.

Why did you dismantle the blades? What was wrong with the shutter in the beginning? Are you sure you got the spacers between the blades back in the correct places also the washers between the front and back frame? The positioning is critical. Picture attached of the order everything has to go back.
I don't think you'll be able to adjust the top speeds enough if they are a stop slow.

ic-racer · Jan 30, 2025

Renzo35mm said:
I'm using my phone camera that can record a video of 240 fps. Then I go frame by frame to measure the exposure time. It's fine for speeds up to 1/250s.

Last time I checked the curtain time travel was about 3 ms. But I couldn't find any information about a specific value in the repair manual.

Anyway, I noticed that the I forgot to oil the pivot point of the slow escapement gears. After that speeds seemed to have lowered. 1/30 now reads 1/40 instead of 1/60. Going to do a few more tests.

The curtains need to travel the same speed across the gap. If one catches up to the other, that will change the speed (250 to 1000).

a constant underexposing of 1 stop in all speeds

All speeds?? Seems like you don't have ability to check the high speeds. Is that correct.

Anyway if the traven time is 3ms, that is way too fast. Slow the blades down to the correct value and see if the slow speeds can then be managed by the spring adjustment.

Renzo35mm · Jan 30, 2025

monopix said:
Why did you dismantle the blades? What was wrong with the shutter in the beginning?

There was nothing wrong with the shutter, but since it's a 40 years old camera, I figured it wouldn't hurt to get a complete CLA.

Are you sure you got the spacers between the blades back in the correct places also the washers between the front and back frame?

Hm, I think I got the brass washers in the wrong position. I took photos of everything but since the washers fell off when I started disassembling the curtains I couldn't figured it out where they go. It's curious that my shutter only has 2 washers, and the other shutter from another FX3 I got in my hands has 4.

I don't think you'll be able to adjust the top speeds enough if they are a stop slow.

I don't have a method to measure speeds higher than 1/250 so I have to rely on pure guess haha, but it's pretty hard to differentiate speeds that high, so there is a possibility that i'm guessing wrong.

Renzo35mm · Jan 30, 2025

ic-racer said:
The curtains need to travel the same speed across the gap. If one catches up to the other, that will change the speed (250 to 1000).

I'm looking at the high speed footage and the curtains seem to be traveling at the same speed (2.5 ms)

All speeds?? Seems like you don't have ability to check the high speeds. Is that correct.

Yep, It was 1 stop too fast in all speeds up 1/250 (I can't measure more than that).

Anyway if the traven time is 3ms, that is way too fast. Slow the blades down to the correct value and see if the slow speeds can then be managed by the spring adjustment.

I did it, but the curtain spring tension has little to no effect on speeds up to 1/250.

Renzo35mm · Jan 30, 2025

I managed to get all speeds (except 1/500 and 1/1000) up to standard:

1/15: 1/13
1/30: 1/35
1/60: 1/76
1/125: 1/111~1/100
1/250: 1/200~1/333

Speeds lower than 1/15 are wildly inaccurate, for exemple 1/2 leaves the curtains open for more than 2 seconds. But I don't expect to use them, so I think is fine.

monopix · Jan 30, 2025

Renzo35mm said:
There was nothing wrong with the shutter, but since it's a 40 years old camera, I figured it wouldn't hurt to get a complete CLA.

I think a lesson learnt. Don't mess with it if it's working OK. There is rarely a need to remove the curtains. I've serviced many FX-3s and similar cameras and, at most, you need to tweak the top speeds a little. What you've done is way beyond what's necessary for a CLA.

Renzo35mm · Jan 30, 2025

monopix said:
I think a lesson learnt. Don't mess with it if it's working OK. There is rarely a need to remove the curtains. I've serviced many FX-3s and similar cameras and, at most, you need to tweak the top speeds a little. What you've done is way beyond what's necessary for a CLA.

Lesson learned, but I still don't see how removing the curtain might have the messed with the shutter. Worst case it would have the operation slower or not work at all, but not make the speeds two times faster.

ic-racer · Jan 30, 2025

Renzo35mm said:
I'm looking at the high speed footage and the curtains seem to be traveling at the same speed (2.5 ms)

Yep, It was 1 stop too fast in all speeds up 1/250 (I can't measure more than that).

I did it, but the curtain spring tension has little to no effect on speeds up to 1/250.

That is too bad, it was just a thought.

I have five FX-3, but never had a shutter problem with any of them; and I have a focal plane shutter tester. In fact, the reliability of their shutters is one reason I got into the Yashica/Cosina system. In fact I just got two Nikon FM-10, which I belive has the same nice shutter.

Renzo35mm · Jan 30, 2025

ic-racer said:
That is too bad, it was just a thought.

I have five FX-3, but never had a shutter problem with any of them; and I have a focal plane shutter tester. In fact, the reliability of their shutters is one reason I got into the Yashica/Cosina system. In fact I just got two Nikon FM-10, which I belive has the same nice shutter.

I agree, they are very nice cameras with great reliability and easiness of repair.

The weakest part of the camera is a plastic lever on the bottom of the mirror box. My first FX-3 came with it this way. Now I always try to reinforce it with some epoxy putty whatever I get one in my hands.

monopix · Jan 31, 2025

ic-racer said:
That is too bad, it was just a thought.

I have five FX-3, but never had a shutter problem with any of them; and I have a focal plane shutter tester. In fact, the reliability of their shutters is one reason I got into the Yashica/Cosina system. In fact I just got two Nikon FM-10, which I belive has the same nice shutter.

Cosina had nothing to do with Yashica. Yes the FM-10 uses a near identical shutter but, as I remember, there is a minor difference in the cocking lever.

ic-racer · Jan 31, 2025

monopix said:
Cosina had nothing to do with Yashica. Yes the FM-10 uses a near identical shutter but, as I remember, there is a minor difference in the cocking lever.

Yes, I forgot, I think it was Kenko, not Cosina, that made the fx-3.

Anyway, I think the shutters are very similar (FM-10 vs FX-3). But I can gladly say I only have these images and have never needed to take the shutter out of any of them.

(FX-3 and FM-10 diagrams from respective assembly manuals).

ic-racer · Jan 31, 2025

Anyway, back on topic, since the shutters may be simlar, this chart is for the FM-10 and may also apply to the FX-3:

ic-racer · Jan 31, 2025

Also, if the OP does not know, the shutter travel times I found here, but since it is a common shutter, there may be more info out there (that I have not discovered yet).

monopix · Jan 31, 2025

ic-racer said:
Yes, I forgot, I think it was Kenko, not Cosina, that made the fx-3.

Kenko never made anything, they sold products made by other companies, maybe including Cosina, that were branded for them. Most Kenko cameras were made by Phenix in China, as was the FX-3.

ic-racer · Jan 31, 2025

My FX-3 are imprinted "Japan" on the base.

I'd like to know where you come up with your information on these cameras. I suspect there is a whole world of informatioin not in the English language concerning Japanese and Chinese manufacturing of cameras.

monopix · Feb 1, 2025

ic-racer said:
My FX-3 are imprinted "Japan" on the base.

I'd like to know where you come up with your information on these cameras. I suspect there is a whole world of informatioin not in the English language concerning Japanese and Chinese manufacturing of cameras.

It says 'Japan' not 'Made in Japan'.

I should ask you where you got the information re. Cosina but I suspect you are just repeating what everyone else says. It's one of those internet myths that keep getting repeated. Probably started by someone who thought the Cosina CT-1 looks like an FX-3 whereas, if you pull the covers off it's obviously a different camera (The CT-1 chassis is what Cosina have used repeatedly for other cameras including the Nikon FM-10).

Conversely, there are many cameras based on the FX-3 chassis and they all originate from Phenix. Some are branded as Phenix such as the DC303 or the DN60/DN66. Others are branded as Kenko like the KF-1n or the KF-2n or the KF-3YC (which is a FX-3 Super 2000 rebadged). Then there is the KF-M1, a variant of the DN66, made for Map Camera in Japan. It has a Nikon mount. I personally converted one of those to Yashica mount by swapping out the mirror box with one from an FX-3. I've also converted a DC303 from the original PK mount to YC by swapping the mirror box. This wouldn't be possible if they weren't all using the same chassis.

Then there is the Yasuhara T981 designed by Shin Yashuhara, an ex Kyocera design engineer who worked on the Contax AX. He wrote a book in which he says Kyocera used Chinese factories to build Contax and Yashica cameras. Only the top-end models were made in Japan. He went to Phenix to have the T981 manufactured and they used a cut down FX-3 chassis with a rangefinder module attached to make the T981.

In short, there is a lot of evidence, circumstantial maybe, that the FX-3 was made by Phenix. There is evidence that the first ones were made by Yashica but the later variants came from Phenix. On the other hand, no one has yet come up with any evidence that Cosina had any input whatsoever.

Picture attached of my Phenix made cameras.
KF-M1 modified for CY lenses
T981
DC303 modified from PK to CY
Vivitar 3800N a rebadged DC303

P.S. I tried to post some links but wasn't able. Not sure why.

monopix · Feb 1, 2025

Here's the links. Don't know why I couldn't put them in the above post. Just wouldn't let me.

Yashica FX-3 Super 4000 anyone?

I recently acquired a Map KF-M1 camera. Made by Phenix in China using a Yashica FX-3 chassis, it has a Nikon lens mount and a top shutter s...

contax139.blogspot.com

Yasuhara T981 一式

This is an independent site dedicated to the Yasuhara T981 camera. It has no association with Yasuhara Manufacturing.All information is supplied in good faith and is believed to be true and accurate. No responsibility is accepted for any consequence of anyone following instructions or using

www.t981.co.uk

ic-racer · Feb 1, 2025

You are well versed in these cameras! Thank you for the information!

ic-racer · Feb 1, 2025

That is your web site, yes? Great resource! For example, nice picture of the mirror box showing the adjustment screws. Helps to see this when inserting the screwdriver into the holes in the front of the FX-3. Expecially since the adjustment is documented in the Contax manual, not the FX-3 manual.

Also, nice writeup on the stiff brake. I have encountered quite a few vintage cameras in which the closing curtain brake has become so stiff the shutter does not complete the cycle.

Hope the OP gets things working again, these are nice cameras to use.

monopix · Feb 1, 2025

Yes, those are my sites. Thanks for the comments.

Yashica FX3 shutter running too fast

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