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Wonloo
Tinkerer
Username: Wonloo
Post Number: 50
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 23, 2012 - 02:16 pm: | 
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Doing a CLA on a Zorki 4 camera that I picked up. The shutter was very sluggish, sometime it didn't even completely close. I have cleaned the shutter by a drop of naphtha at all pivot/axle points and exercised all speeds for at least 20 times. The slow speeds ,1 - 15 + 60, are within 20% which is fine. But the high speeds, 30, 125-1000, are about one stop too slow. I repeated the cleaning step one more time and oiled all points with a pin drop of watch oil and got some improvements. Now, it is still about 3/4 stop too slow. I can't find any information on how to adjust the high speed.
Can someone provide any instruction on the high speed adjustment? Thanks. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1191
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 25, 2012 - 07:12 pm: |
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That seems very odd. There really isn't an adjustment for slit width (the control for the higher speeds), as the release of the #2 curtain is done directly by the #1 curtain drum. The curtain position could be off from a replacement, but this would not give a consistent 1-stop error: the error that caused 1000 to run 1 stop slow would only affect 500 by 1/2 stop and so on down the line. The only thing I can think of that could cause this is the curtains running slow, but that amount of slowness would seem almost impossible. Maybe there is some drag causing hesitation in the #2 curtain? Possibly needing lubrication at the release lever up under the shutter speed dial, or else maybe some dirt in the big gear at the bottom of the curtain drum causing one curtain to hesitate while the other one continues on? |
Wonloo
Tinkerer
Username: Wonloo
Post Number: 51
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 26, 2012 - 06:32 pm: |
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Hi, Rick. I followed the instructions on your web site to do the CLA. Thank you again on this one. Here is the timing test result that I got:
30 - 36ms (very good,it was 55 before I started)
60 - 19 (again very good but that is low speed)
125 - 12.4
250 - 6.4
500 - 3.3
1000- 1.7
The base timing of the high speed at 1/30 is almost right on. If the 1/30 was 48ms that will make sense, every speed is twice (or close to) as fast as the previous one. Looks like the timing slots on the curtain drum is working. If it was the release level of #2 curtain causing the delay, I will think it will be a fix offset (say 2ms) for all speeds. 125 will be 10 (8+2), 250 will be 6 (4+2) and so on.
I will try your suggestion and see how it works. Thanks.. |
Anbi
Tinkerer
Username: Anbi
Post Number: 1
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 15, 2012 - 03:46 pm: |
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Hi, Rick.
Thanks for your CLA guide.
What do you think may be the problem in my zorki4 if I get the following 1/times on the left and right side of the frame?
labeled left right
30 28 31
1000 530 490
500 370 230
250 250 150
125 150 90
60 130 80
All slow speeds are ok.
Thanks |
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