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Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 30, 2005 - 09:22 pm: | 
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Today I went taking some pictures with my "battlefield" Contax RTS II and, when I was in the middle of the woods, I had a bad surprise: with exposure times longer than 1/60 the camera would leave the shutter open for times absurdly long. It doesn't seem being a problem of light metering: while the shutter is open (sometimes, setting the speed to 1/15th, it would stay open several seconds!!), pushing the light-metering button on the front of the camera, in the viewfinder would appear the correct settings.
Back home I have checked the speeds: 1/2000 -> slow, 1/1000 - 1/250 more or less correct; 1/125 -> 1/90 - 1/30; 1/60 -> 1/40 - 1/15. The mechanical shutter release is amazingly precise and reproducible (1/50), therefore I can guarantee that, for the mechanical side, the shutter has no problems.
This camera, aesthetically, is ugly but, functionally, has always been great and the shutter very precise (I shoot only slides...).
I have quite some experience in repairing mechanical cameras, I also have some basic knowledge of electronics and tons of broken cameras for parts..
I have invested a lot in focusing screens for this camera plus I really enjoy several of its features (good mechanical construction, fantastic release button, viewfinder, etc).
Although, technically, I would be able to put together a couple of reliable FR/FR-I, I would really like to be able to fix this RTS II
My hypothesis is that a capacitor connected to the quartz of the shutter is out of order.
Is there anybody that could confirm / correct my diagnosis?
Tonight I have opened only the bottom of the camera and I have seen a blue drop-shaped capacitor that reminds me of Contax 139 (before 1980?) and/or Yashica FX-D: would it be that the "culprit"?
Otherwise, where the "right" is / are located?
I have the impression that, with cold weather, the camera would misbehave more (or probably it is going more and more downhill...): if this is true, would be helpful conducting tests like warming up / cooling down a single component of the circuit at the time, in order to find the culprit or the physical interaction would itself bias the bahavior?
Thanks for your help!
Paolo |
Michael Linn
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 30, 2005 - 10:31 pm: |
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Contax typically provided external battery packs for cold weather. I have one for my 137.
I don't think it could be a capacitor problem as they are tanatlum and unlikely to fail. Is this happening only on auto? If so in order to test the camera I would suggest that you return to the same conditions, meter the shot as if for auto exposure, but manually set the exposure per the readout in the viewfinder and see if that provides the indicated exposure. |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 31, 2005 - 08:32 am: |
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Thanks Michael,
The behavior is the same both in manual and auto: that has been the very first thing I have tried in the field... As for the temperature, the coolest spots were anyhow above 41F (5°C) and the problem persisted once the camera has been stabilized at room temperature at home (~64F / 18°C)... The battery was good yesterday morning (~6.2V), but I didn't check when I was back... However, no sign of low battery and the very same battery was used to re-test the shutters of another RTS-II (this one has been always bad on times faster than 1/250) and a couple of FR / FR-I, without any problem...
It could be that some dirt had accumulated on the circuit and, with condensed humidity it causes the problem. However, either there is some component that drains quite some energy or I doubt this would be the cause...
Tonight, when I'm back from work I'll check the battery, test the speeds again and, if I have some time, I'll take out the top cover.
In the past I have used this very camera in much more demanding conditions (~20 F / -12°C) for hours without any problem...
As I have said in my previous posting, the temperature correlation is just an impression. ...Too few experimental points to draw a conclusion...
The idea of a faulty capacitor derives from the fact that, for the little I know about capacitors, those are the elements that are used for “counting” the cycles of a quartz: if that capacitor is leaking, the effect is much more obvious on longer exposure times...
Thanks!
Paolo
PS Unrelated with my topic, but more related to your camera: now that you have mentioned the 137, I once had one that would burn the first shot when just switched on or after several minutes after the last shot... It was quite weird... Anyhow, 137, 167 have also the internal motor for winding the film, a good battery drainer, especially in cold weather!!! |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 31, 2005 - 09:00 pm: |
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OK, here is some update: I completely exclude battery issues (6.3 V before the test and 6.3V after the test) and, if the temperature has any effect, now it seems that the higher, the worst... I will leave the camera in the fridge overnight and we will see.
I have removed the top cover and I have found much less dirt than expected. The problem, not surprisingly, persists even after cleaning all the contacts.
That's all for today.
Paolo |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 01, 2005 - 08:08 am: |
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After a night in the fridge, the problem persists but seems slightly improved than worsened... Now I'm trying in the freezer (also in the attempt of eliminating some residual humidity: it is in an open Zip-Lock bag in a no-frosting freezer; the bag will be closed as the camera will be removed from the freezer).
Another piece of information that I didn't post is that the night before going out with this camera, I have tried it on several settings and several shutter speeds, without a film, without noticing anything wrong... Unfortunately I didn't test it with the shutter tester...
Paolo |
Mikko Häkämies
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 28, 2006 - 10:47 am: |
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Sorry to revive such an old thread, but I'm curious as to whether you managed to figure out what it was that was bugging your Contax? Not surprisingly, mine has come up with the same symptoms. I'm gonna take it to get fixed asap, but it would be good to know what's wrong with it beforehand. |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 17, 2006 - 08:42 am: |
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Hi Mikko,
My apologies for neglecting this thread myself! I have given up for the moment, since I didn't find any useful information...
Lately I have been busy at work and didn't have time to take too many pictures...
I love the feel of that camera and the pictures taken with those lenses but, I'm afraid, there aren't too many chances of getting it fixed for a reasonable price... I'd should screen among all the Contax/Yashica bodies, select the ones that have a reliable shutter and use them...
How did it go with your?
Paolo |
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