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Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 1
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 30, 2011 - 06:46 am: | 
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Hi everyone,
I just joined the forum, even though I've been tinkering with cameras with your help for years (thanks!)
I picked up a Koni Omega 90mm 3.5 recently because it looked good cosmetically. Unfortunately, that's all that's good about it. The shutter is very sticky at slow speeds, sometimes tripping quickly like a very fast shutter speed or staying open altogether.
I read another post on the site about getting access to the shutter by removing a couple 1mm screws then unscrewing the front lens group, but those screws don't exist on my lens, which is an earlier one. Anyone have any ideas, or done this before?
Thanks again! |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 23
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 30, 2011 - 06:15 pm: |
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The Hexanon lens has a built-in hood so you cannot turn it by holding on the side. I used a 1" PVC pipe and a rubber glove to open it from the name ring. After removing the front lens, the following steps are pretty straight forward for a leaf shutter. Nothing really special about it. You will need to give a good cleaning. I let it runs dry and it seems to be OK.
For some reason, Hexanon has good amount of lubricant in it. My other Supper Omegon 90mm lens seems to have less. |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 2
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 01, 2011 - 10:30 pm: |
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Thanks, Wonloo! Did just what you suggested and it worked great. Everything inside looks clean and dry. But, the shutter blades are a bit stiff opening and closing. Is this normal, or, since there is a spring loading the blades, should they snap back and forth without help? |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 24
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 02, 2011 - 01:44 pm: |
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The movement of the blades should be very snappy. Here is a step you can try to clean the shutter. Get some Q-tip and naphtha (lighter fuel). Apply some drops of naphtha around the lens tube on the shutter blades. Fire the shutter at B speed several times. This should normally free the shutter up. The naphtha at this moment serves as both detergent and lubricant. After this, clean the blades with Q-tip and wait for the shutter to be completely dry then fire the shutter at different speeds. If you fire the shutter while the shutter is still wet, the naphtha may stick the blades together. Omega is a interesting 120 range finder. Have fun. |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 3
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 02, 2011 - 04:55 pm: |
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Thanks again, Wonloo. I owe you one. The shutter seems to have slow blades as well as binding slow speed gears. I have pulled the slow gears out and cleaned them in naptha, but they still feel slightly rough, just enough to hold up the mainspring. I can move the blades manually with a thin screwdriver on one of the prongs that triggers them open, but they certainly don't move freely, and don't spring back on their own. I'll start by using your technique to clean them, but the slow speed gear situation sounds like it might not be easy repaired. |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 25
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 02, 2011 - 06:20 pm: |
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I forgot to tell you don't take the speed gears out before all tricks are exhausted. Any way, without the speed governor, you still should be able to fire the shutter at B and the highest speed, 1/500. Try to free the blades first, worry about resetting the timing later.
Do not further disassemble the shutter. Based on your description in the first post, your shutter is most likely just needs cleaning and some exercise. |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 4
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 02, 2011 - 07:01 pm: |
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I swabbed the shutter blades with naptha and that freed them right up. Now they are snappy and close instantly. But the speed gears still feel as if they are bottoming out. I even disassembled another lens to compare the speed governor side by side,and this one is much rougher, even after cleaned thoroughly in naptha until it sparkles. Nothing looks worn or out of place, and it unwinds smoothly. But it doesn't want to wind easily when the cam contacts it. If I depress ever so slightly on the 3-position prong that disables gears, but still leave the gears for speeds 1/30-1/250 engaged but with slightly more room between the teeth, it frees right up. It's as if two gears are too close to each other, and the teeth bottom out. Strange. |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 26
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 03, 2011 - 06:54 am: |
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OK, looks like the cleaning part of the CLA is completed. Unless there is something bended, the gears normally will work just fine without lubricant so we will skip that for now.
When everything in place, how does the slow (1 to 1/15) range works? 1) blades don't open, 2) open but gears don't turn, 3) gears turn but blades won't close, 4) works but too slow.
Since you got the shutter opened already, can you post the pictures of the whole shutter and the speed governor? It will help us and the others to better understand the problem. |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 5
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 03, 2011 - 08:43 am: |
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I'll take some pics and post them on here. The problem seems to be a combination of 2 and 3. The blades open and the gears start to move a little, but then the gears stop part way and the shutter doesn't close, unless I give it a nudge. |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 6
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 03, 2011 - 11:34 am: |
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These aren't great, and I'll happily take more if they aren't explicit enough. The first shows the shutter cocked and ready to fire. The second pic shows where the cam and gears stop once I have tripped the shutter  |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 27
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 03, 2011 - 06:47 pm: |
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I label your picture with:
a) the range selection level - selects speed ranges, 1 - 1/15, 1/30 - 1/250 and disengage for 1/500
b) the speed selection level - selects speed within range
c) the speed control arm - provides delay to the main spring
d) the main spring - opens and closes the shutter blade
e) the speed adjustment screw
When the shutter gets stuck, do you have to push it all the way (the main spring is too weak) or just a push and it will complete the cycle (something got stuck between the gears)? You should be able to push the speed control arm smoothly (with some resistances) when the main spring is at the cocked position. If you only have problem with the slow speeds, there is one place you can check: near (or on?) the range selection level, you will find a catcher looks like the one in the clock that controls the second movement. Oil a little bit (a pint drop) at both tips and the axle. That brought the Klio shutter on my Zeiss Ikonta back to life. I hope that was the problem.
If this still didn't help, try loosing the speed adjustment screw under the speed selection level. Move the speed governor in or out to see if that will help. Some time the control arm gets stuck when the speed governor is at the far end. You will have to adjust the speed anyway. |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 28
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 03, 2011 - 07:04 pm: |
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Sorry, it should be a pin drop of oil, not a pint drop! |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 7
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 04, 2011 - 11:09 am: |
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Luckily I didn't drop it in a pint of oil, but I've been tempted! Great labels on the picture. Those help a lot and serve as a great reference for how these things work.
I don't know what happened to my second picture that shows where things come to a stop. I'll try to repost it. But in words, in the slowest speed range (level "a" set closest to the shutter blades), the speed selection lever (b) begins to move under the power of the mainspring, but then hangs up part way down. It acts exactly like something got stuck between the gears, completing its cycle if I give it a small nudge. It tends to stop at the same point or two each time.
But there is nothing on any of the gears. They are spotless, so I am inclined to think there is a burr somewhere in the gear train. It only hangs up during the slowest speeds, but I don't think the issue is in the gears added by the range selection level (a) at the slowest speeds. I think they add just enough extra drag that the mainspring cannot overcome the roughness on the other gears. Trouble is finding the source of that roughness. I can't. The feeling is transferred through all the gears.
With the shutter cocked, I can move the speed control arm, but it certainly doesn't move as smoothly as the one on my other shutter.
Incidentally, loosening the speed adjustment screw doesn't seem to free things up either. There is very little back and forth movement afforded by the oversize hole in the speed governor. And when I add the plate that the speed selector arm rides along, the speeds seem too slow, even with the governor pushed as far as it will go towards the center. |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 29
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 04, 2011 - 06:52 pm: |
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Here are the steps that I will do next:
1) mark the place where the speed selection level (b) stops with a marker on the governor.
2) take the governor out, manually move the level to the marked place and inspect where it gets stuck.
3) if still cannot identify the problem, before disassembling the governor, I will do one last cleaning to be sure.
4) I will submerge the governor in the naphtha, rinse it well and exercise the governor in the naphtha. This will ensure no dust gets trap between the gears. It should work smoothly in the naphtha if nothing is damaged.
5) if this solves the problem, let the governor completely dry and try again. If it gets sticky again, try some oil.
If nothing works then it is time to disassemble the governor and start the repair work. I hope you don't have to go that far. |
Bgairborne
Tinkerer
Username: Bgairborne
Post Number: 8
Registered: 03-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 15, 2011 - 10:08 am: |
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Wonloo, I really appreciate all your help with this. I did the final cleaning again (three more times) and still no improvement. But I can't see a way to easily disassemble the governor. There's one screw, but the rest looks riveted and I'd hate to make it worse than it is. I might just live without the slowest speeds on this lens. Bulb still works, so I suppose I can always stop way down.
Interestingly, I don't seem to be able to adjust the remaining speeds to be a littler faster. The adjusting screw (e) in the diagram allows a little movement, but still not enough to bring the speeds equal with my other lenses, which are accurate. |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 31
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 16, 2011 - 03:31 pm: |
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The speed adjustment screw has a small movement but the difference is significance. The main difference is between speed ranges. If not properly adjusted, 1/15 may be close to or even faster than 1/30.
Sorry, cannot help further without having the shutter on hand. |
