IIIg slow speeds

[qqphot]

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One of my two IIIg bodies just came back from service with its slow speeds now all firing at the same speed (i guess around 1/30). T still works normally though.

I feel like this is probably due to an oversight in reassembly (since the slow speeds worked correctly before) - any speculation on what happened?

I've had a IIIf apart and done basic cleaning and rangefinder repair, but nothing on a IIIg. This last repair visit took 9 months so I'm not eager to send it back for another round.

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[earleygallery]

You really do need to send it back.

[jerzy]

if the IIIf you repaired has self timer than taking off body shell on IIIg is not very different, you need to span ST before taking off the lever  and underlaying componenets.
Then you may dismount the front plate and check if the rod connecting slow speed escapement with the shutter is positioned correctly (however I believe it is). Taking off top cover is more difficult, unscrewing the small collars around the windows requires special tools. But before you do anything - check following: - set speed dial to B, slow speeds to 1 and run the shutter. After you press release the shutter will stay opened as long the button is depressed. When you release the button - do you hear the noise of slow speeds escapement? Is the second curtain delayed after releasing the button? Setting slow speeds on 1/5 - could you see the delay between releasint the release button and second curtain closing? Does it sound as 1/5th or rather as 1/30 (50)? Btw. 1/25th is engaging sthe low speeds escapement for a short delay. Setting on black lightning (flash position, approx 1/50) is the slowliest speed when the slow speeds escapement is not yet engaged. So pls check firstly as described above and let me (us) know. I suspect what could be wrong but you would need to open the camera. So if you have repair warranty do send it back as suggested above

[qqphot]

4 hours ago, jerzy said:

if the IIIf you repaired has self timer than taking off body shell on IIIg is not very different, you need to span ST before taking off the lever  and underlaying componenets.
Then you may dismount the front plate and check if the rod connecting slow speed escapement with the shutter is positioned correctly (however I believe it is). Taking off top cover is more difficult, unscrewing the small collars around the windows requires special tools. But before you do anything - check following: - set speed dial to B, slow speeds to 1 and run the shutter. After you press release the shutter will stay opened as long the button is depressed. When you release the button - do you hear the noise of slow speeds escapement? Is the second curtain delayed after releasing the button? Setting slow speeds on 1/5 - could you see the delay between releasint the release button and second curtain closing? Does it sound as 1/5th or rather as 1/30 (50)? Btw. 1/25th is engaging sthe low speeds escapement for a short delay. Setting on black lightning (flash position, approx 1/50) is the slowliest speed when the slow speeds escapement is not yet engaged. So pls check firstly as described above and let me (us) know. I suspect what could be wrong but you would need to open the camera. So if you have repair warranty do send it back as suggested above

Thank you so much as usual, Jerzy -

Yes, i've disassembled the IIIf with ST and also removed the top cover without screwing up much.    With speed dial at B and slow speeds at 1, there is no delay of the second curtain or any sound of the escapement after releasing the button. With slow speed at 1/5 (well, 1/4, IIIg has 1/4 mark) there's still no apparent delay after releasing the button either, more like 1/30 than like 1/5, and no sound of escapement. This is different from what happens with my working IIIg in both cases.

Regardless of whether I send the camera back or not, I'd still rather understand what's happening and how it works than remain ignorant! Thank you for your many very helpful explanations.

[jerzy]

well, missing sound of escapement confuses me a bit, but still - I believe that one gear is not positioned properly. Photo below shows IIIg with spanned shutter, notice position of the pin marked orange, there must be a small gap between pin and black, L-formed bar on escape. Btw - it looks very similar in IIIf (and postwar IIIc). Gear with the pin rotates with the 2nd curtain and after 2nd curtain closes the pin shall be in position marked green, thus pushing the bar left (blue arrow). Bar disangages part of slow speeds escape (black arrow) allowing for faster return of escapement to the home position, thus being faster ready for next shot.
During repair, after reassembling the shutter it is neccessary to position the gear with pin correctly, like on the photo: shutter spanned - there is a small gap, shutter released and closed - pin is pushing bar to the left. If this is done opposite (shutter spanned and pin is pushing bar) than part of escapement is disengaged and it runs much faster but it runs. It does not produce this typical noise (part marked black is detached), there is only noise of gears. You may notice a small hook on the left side of the black bar - this is where the bar on the inner side of front plate is hooked, itis connected to the slow speed dial and disengages part of escapement for faster slow speeds (IIIf is constructed in the same way). 
I believe that your problem is in wrong position of gear with the pin, this may happen when the repairman was distored by something when reassembling and did not chek it. Pin shall be unscrewed, repositioned and screwed again - after assembling the shutter. 

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(do not be irritated with the small film debris - photo is part of repair documentation, this is what I found after removing the front plate)
The second mistake that usually happens to not very much experienced repair person is the ST not working properly - after reassembling the shutter the sprocket drum needs to be positioned correctly. Otherwise ST is producing the noise (it runs) but does not release the shutter. Same is valid for IIIf with ST.

[qqphot]

This is interesting - thank you very much for the explanation and the pictures. I am not sure I'm up for the degree of disassembly needed - taking off the shell is no problem but I don't want to have to disassemble and then later readjust the shutter.

[stvn66]

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Send it back, it should be a priority repair under guarantee.

[qqphot]

On 7/24/2024 at 12:25 AM, stvn66 said:

Send it back, it should be a priority repair under guarantee.

not to go into details but this was already a re-repair and took nine months.

[qqphot]

Jerzy - thank you very much for your suggestions. I didn't have much trouble with disassembly though it took a bit of care to remove the front plate without taking the top cover off and I imagine it will be a bit challenging to put it back.   I wonder if these pictures confirm your thoughts or suggest something else. I've left it apart so I'm happy to supply more photos.  It does not appear that the slow speed gear train runs when the shutter is fired on the "1-30" setting regardless of the position of the slow speed dial.

(BTW is this a reasonable amount of lubricant? It seems like someone slathered an awful lot all around inside it.)

Here is the mechanism with the shutter released:

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Shutter released (above)

 

 

Shutter spanned (above)

 

Rear of front cover.

Whole slow speed mechanism (released).

 

Edited August 13, 2024 by qqphot

[jerzy]

Hi, I believe that with your skills you will manage assembling the front plate easily. Just press down the rangtefinder cam down when placing the front plate (but you must have the same when removing it). When mounting take care that the brass bar is hooked correctly on the L-bar on escape - there is a hole in the front plate to check it.

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You made great photos, we may see that the gear with the pin is positioned correctly. So my guess was not quite good. But I have impression that the L-bar is stuck in most left position, When the shutter is spanned it shall move to the right, here it looks like it does not (orange line shows positioning in comparison to the screw hole).

Is it possible to shift the bar right/left when the shutter is spanned? If it does not move than it could be dirt in escape itself (rather not) or what is more probable the screw blocks the L-bar. There are 2 screws fixing escape mechanism to the die cast, both look very similar but one is a bit shorter. If they are swapped during assembly than the longer screw in position marked is blocking the L-bar. Losen this screw a bit and check if L-bar may be shifted. If yes than swap both screws. Btw - if you have it so far you may dip the slow speeds governor (slow speeds escape) in lighter fluid just to give it CLA. Yes, there is a bit too much greas on gear and Lbar but it does not harm. Unless it is hard than wash it.

hope that I am correct now, let me/us know.

[jerzy]

vor 4 Stunden schrieb qqphot:

It does not appear that the slow speed gear train runs when the shutter is fired on the "1-30"

I think it does, but only on shorter speeds of slow speeds. But you may check it as well when the front plate will be on its place - when shutter is spanned push with toothpick here, you shall hear the noise of working gears on slower slow speeds and you shall notice less force needed for faster speeds (like 1/25, etc) You will notice as well that the L-bar will be moved left (in the hole on front plate) depeneding on the position of slow speeds dial. It is complicated how I wrote it, sop in other words L-bar when moved to the left disengages part of gears in escape, escape runs faster and the noise in much less

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[qqphot]

11 hours ago, jerzy said:

Hi, I believe that with your skills you will manage assembling the front plate easily. Just press down the rangtefinder cam down when placing the front plate (but you must have the same when removing it). When mounting take care that the brass bar is hooked correctly on the L-bar on escape - there is a hole in the front plate to check it.

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You made great photos, we may see that the gear with the pin is positioned correctly. So my guess was not quite good. But I have impression that the L-bar is stuck in most left position, When the shutter is spanned it shall move to the right, here it looks like it does not (orange line shows positioning in comparison to the screw hole).

Is it possible to shift the bar right/left when the shutter is spanned? If it does not move than it could be dirt in escape itself (rather not) or what is more probable the screw blocks the L-bar. There are 2 screws fixing escape mechanism to the die cast, both look very similar but one is a bit shorter. If they are swapped during assembly than the longer screw in position marked is blocking the L-bar. Losen this screw a bit and check if L-bar may be shifted. If yes than swap both screws. Btw - if you have it so far you may dip the slow speeds governor (slow speeds escape) in lighter fluid just to give it CLA. Yes, there is a bit too much greas on gear and Lbar but it does not harm. Unless it is hard than wash it.

hope that I am correct now, let me/us know.

Jerzy -- Yes, I think you are correct! Well - if I loosen this screw, the L-bar slides side to side easily (when the shutter is spanned), and the slow speeds function again.  When it is tightened, the L-bar moves only with quite a lot of friction and slow speeds do not work.

However, I've taken both screws out and the one in question (orange) is already the shorter of the two. The other of the two screws holding the escapement has a washer, while this one does not, but according to the service manual this is how it's supposed to be:

 

As an experiment I exchanged this screw with the same one from my other IIIg body(s/n 934244 vs 889866), and the problem follows the screw - this camera's slow speeds work when the other camera's screw is installed, and the other camera's slow speeds don't work when this camera's screw is installed. But measuring the two screws shows only a difference near the margin of error of the caliper, and they're visually the same:

Could the dimensions of the screw be this critical, or is something else wrong which makes the escapement too sensitive to it?  I suppose I could try to shim the screw by 0.01mm or polish off 0.01mm from the end but that seems like a wrong idea.

Edited August 13, 2024 by qqphot

[jerzy]

great, you found it! it is only 0,02mm that makes a diifference, it could be that there are small deviations between escape mechanisms. Just file the top of screw a bit off. For the others to understand the problem - the "wrong" screw goes too far in and is blocking the support on which L-bar is fixed. This support shall move freely. Btw - the same effect is with IIIc and IIIf, too long screw will block L-bar 

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[qqphot]

18 minutes ago, jerzy said:

great, you found it! it is only 0,02mm that makes a diifference, it could be that there are small deviations between escape mechanisms. Just file the top of screw a bit off. For the others to understand the problem - the "wrong" screw goes too far in and is blocking the support on which L-bar is fixed. This support shall move freely. Btw - the same effect is with IIIc and IIIf, too long screw will block L-bar 

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Yes, it seems you were exactly right about the problem (as usual.)  To be sure, I placed a 0.05mm shim under the screw and tightened it down, and it continues to work correctly. So maybe I'll file it down a bit or just leave the shim. It's easily accessible with the camera assembled, anyway.

When I reassemble the camera, is it likely that the flange-film distance or parallelism will need to be recalibrated? I hope not, since it seems to require specialized tools. Everything supporting the mounting ring seems quite rigid and there doesn't seem to be much to adjust, but the repair manual does show a quite extensive procedure (sheet 7).

[jerzy]

vor 4 Stunden schrieb qqphot:

When I reassemble the camera, is it likely that the flange-film distance or parallelism will need to be recalibrated?

usually not. As long as the surfaces marked X and the inner part of the lens flange are clean there should everything fine. Procedure described in Service Manual is more relevenat if either front plate or lens flange has been replaced. Very rarely (in IIIc - IIIg) there are some shims between lens flange. Of course they must be placed in the same order. And one hint - if you notice that when screwing the löens on the camera the screwing starts to go hard around 5-6 oclock (position of focus knob) then there is something with parallelism. And if start to losen a bit the 4 screws the fix the flange it goes fine again this is a sign that some shims under the lens flange are missing or are in wrong position. One should as well well carefull not to swap lens flanges between cameras - there is a good chance that distance to film plane will be out of tolerance. And then you need special tools as described in manual.

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[qqphot]

Fantastic - I checked for shims while disassembling and didn't find any, so I won't worry unless focus is off.   I will need to patch some small areas of cracked vulcanite - I recall there is some sort of wax that can be used, but I can't find anything online that looks promising.

I just re-discovered one more problem with this camera as it came back to me from its last repair. There's a narrow underexposed band at the edge of each frame shot at 1/125 and a little bit on ones shot at 1/250. I don't see it at 1/500 or 1/1000. It might happen at 1/60 but I neglected to try.  The problem existed already before I disassembled it to fix the slow speeds, thankfully!  It first appeared in my negatives after the camera came back from repair most recently. Other than this band, speeds are good and nicely geometric.

I'm used to overexposed bands from crud impeding the progress of the shutter, but I'm more puzzled by this.

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Any speculation?

Edited August 15, 2024 by qqphot

[jerzy]

for patching small üieces of vuclanite I use hard wax, smethong like this https://www.ebay.de/itm/404480912648?_nkw=hartwachs+reparatur+set&itmmeta=01J5BDFFHP4Q41BB25V9WPS20V&hash=item5e2cf0ed08:g:7MQAAOSw0bJk-xjx&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKk%2BohGNjy%2FBVcnLw%2F6ANYUddV0Vusz%2BzKtlfhdQmV9YvQl%2BF7vi%2F6ZdCh6Y%2BY1IhOEBCfB1IHesWYNtGeJUvRUKLaRHIX61O7%2FPeB0dih6IsOezVEU1EHjQjbiKyvPVjd5P5h2Ce52xODABpM0DVF2TxAzlPX6FNolE6rVNymOonUD372p7q7b0kMjDUwAhRcb2yrqw9pwdb5xx8y%2BQ6%2FhiRMLdovom1Wa06kUruZsw5HqXxQw5l%2BETXLB1R6nSIAo9PgvJOfTI%2FpegGBORWgX9uHHLeyxwAF2slBLRg9ZbeA%3D%3D|tkp%3ABFBM_Pi97apk

I have no idea what could cause underexposing on 1/25 and 1/250 but not 1/500 and 1/1000. It could be just coincidence. Motive on negatives does not allow me to judge if undexposed stripe is at the beginning or at the end of the frame. I assume it  is an the end. In such case it could be curtain brake a bit misaligned. Set speed on B, lens off, release and hold the shutter. The edge of opening curtain shall be approx 2-3 mm behind the edge of the frame. Readjust brake if this is not.
Alternatively this could caused by bouncing if opening curtain, very hard to check without appropriate equipment. Bouncing could be caused as well by curtain brake being too weak - readjust.

 

Edited August 15, 2024 by jerzy

[qqphot]

1 hour ago, jerzy said:

for patching small üieces of vuclanite I use hard wax, smethong like this https://www.ebay.de/itm/404480912648?_nkw=hartwachs+reparatur+set&itmmeta=01J5BDFFHP4Q41BB25V9WPS20V&hash=item5e2cf0ed08:g:7MQAAOSw0bJk-xjx&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKk%2BohGNjy%2FBVcnLw%2F6ANYUddV0Vusz%2BzKtlfhdQmV9YvQl%2BF7vi%2F6ZdCh6Y%2BY1IhOEBCfB1IHesWYNtGeJUvRUKLaRHIX61O7%2FPeB0dih6IsOezVEU1EHjQjbiKyvPVjd5P5h2Ce52xODABpM0DVF2TxAzlPX6FNolE6rVNymOonUD372p7q7b0kMjDUwAhRcb2yrqw9pwdb5xx8y%2BQ6%2FhiRMLdovom1Wa06kUruZsw5HqXxQw5l%2BETXLB1R6nSIAo9PgvJOfTI%2FpegGBORWgX9uHHLeyxwAF2slBLRg9ZbeA%3D%3D|tkp%3ABFBM_Pi97apk

I have no idea what could cause underexposing on 1/25 and 1/250 but not 1/500 and 1/1000. It could be just coincidence. Motive on negatives does not allow me to judge if undexposed stripe is at the beginning or at the end of the frame. I assume it  is an the end. In such case it could be curtain brake a bit misaligned. Set speed on B, lens off, release and hold the shutter. The edge of opening curtain shall be approx 2-3 mm behind the edge of the frame. Readjust brake if this is not.
Alternatively this could caused by bouncing if opening curtain, very hard to check without appropriate equipment. Bouncing could be caused as well by curtain brake being too weak - readjust.

 

Surely this is the problem.

 

(it turns out my old samsung phone has a "slow motion" video mode at 960 frames per second)

I haven't ever fiddled with a curtain brake before, so I constructed a tool to adjust the tiny eccentric. I was able to adjust it slightly so that the curtain stops beyond the edge of the frame. Hopefully this won't have messed anything else up.

Edited August 15, 2024 by qqphot

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[jerzy]

very useful feature! and now it is as well why there is no stripe at 1/500 and 1/1000 - slit is narrow and before the 1st curtain bounce the 2nd curtain closes the slit

[qqphot]

8 hours ago, jerzy said:

very useful feature! and now it is as well why there is no stripe at 1/500 and 1/1000 - slit is narrow and before the 1st curtain bounce the 2nd curtain closes the slit

Yes, adjusting the brake worked well:

 

Before ^^

 

After ^^

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Seems to be working properly now at all speeds!  Thank you again, Jerzy - your explanations are always wonderfully educational.