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Thomas1
Tinkerer
Username: Thomas1
Post Number: 6
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 19, 2012 - 09:10 pm: | 
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Bought a Canon 7s and it has slow speed "run on" noise after shutter completes the exposure and the shutter releases if button pressed even though wind not completed. I have seen the posts on sticking clutch preventing freewheeling return after slow speed shutter completes exposure. I may be able to be happy with that for now but the shutter being able to be tripped without a complete wind is a little concerning. Could there be a spring that has come loose under the top cover that operates a latch that would, if not loose, prevent the shutter tripping before a complete wind? Thanks for all responses. These Canon 7's are some awesome machines. Thomas Shafovaloff |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 54
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 20, 2012 - 11:40 am: |
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Does this happen at all shutter speeds? My 7 had a different issue, but could be related. I haven't made it to this camera yet, but I'm starting with a thorough cleaning of slow speed assembly and related (bottom of shutter carriage).
jeff. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 7
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 20, 2012 - 04:27 pm: |
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No, the noise does not occur at all shutter speeds, just those below 1/60 and the noise changes. A bouncing noise begins [detectable audibly] at 1/30 and 1/15. At 1 second, 1/2 and 1/4 a buzzing after the shutter completes the exposure is definite, barely perceptible at 1/8. The longest buzzing is at 1 second diminishing in length of time, then bouncing noise at 1/15 and 1/30. Visually, the shutter seems to operate fine for all shutter speeds. Does anyone know of progressive shutter refinements occurring through the end of production for the 7s? It is my understanding that the viewfinder and rangefinder adjustments along with the design of the clear plastic meter view were changed.[I think that is all.] |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 8
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 20, 2012 - 04:39 pm: |
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Hollenbj, Jeff, It looks like someone took the top off the camera and didn't know how to replace it right. The ASA and shutter speeds do not match with the meter graph when compared to other 7s cameras. Also, it looks like a "set bearing" has been left off the micro spring under the dial of the meter High - Low selector. The tops of these cameras fit very close and will pinch the wires for the meter if not done right on reassembly and well what else is there ......[not mentioned in the 7 "repair manual]."? |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 55
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 21, 2012 - 11:48 am: |
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Any influence on the slow speed bounce and buzz? You describe the exact same problem as on my 7 (no s). I was going to start my search near the slow speed assembly, where it needs to reset after shutter fire. The 7 is next on my list of "to do" cameras. I really like that camera.
Yes, the top zone is tight (I just took a quick peek). I think my camera probably had an entry at some time as well, similar problems with ASA setting and meter, etc. Again, I haven't yet made a concerted effort to repair any of these issues. Hopefully soon.
jeff. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 9
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 21, 2012 - 03:37 pm: |
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Jeff, if you can, get a picture of a 7's graph on a working camera. I compared to the book and some on ebay to make sure I got it right and in addition, on the 7 and 7s that I cleaned up I took a digital picture to make certain I would know how to set it up so it was put together right. On reassembly just match the graph up before putting the speed selector on. Use the 1/1000 sec. setting and ASA/DIN 400/27 reference. The screws on the speed selector are best removed with it set on 1/1000, and ASA/DIN set at 400/27 because on this setting you can get to all three set screws for removal and reassembly. Do not remove the two screws for the sensitivity selector on the rear of the camera as there is a bearing that may slip out, internally, that provides the positive position when the knob is moved and if removed it will take you over an hour to reassemble, at least that is what it took me = after I realized the bearing had come out. It is not necessary to remove these anyway to take the top off. There is tape, on the 7s holding the wires close to the body structure that may be deteriorated. On reassembly, use scotch tape to replace it. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 10
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 21, 2012 - 04:44 pm: |
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Hollenbj, Jeff, as for your question concerning what may influence the noise produced at slow speeds, I do not know what causes it beyond what has already been posted - previously. My bet is that the "clutch" mentioned is in need of lubrication/cleaning (Ronson) and the reset causes the noise because the shutter operates normally through completion of the exposure and the noise comes afterwards, like you say. The 7s that I previously worked on does not make the noise. On reassembly of the top be careful with the springs around the winder, and check that the counter and reset operate before putting the top on - it is better to be careful than have to remake one after a pinch - but that can be done with a little ingenuity - perhaps even better than original. But why have to? |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 11
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 21, 2012 - 06:13 pm: |
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No need to remove completely the screws on the speed selector, just loosen sufficiently to remove the speed selector dial, as they are of different sizes (lengths)and difficult to re-install if completely removed.[for this novice] Also, for others who may read this, the High Low selector for the Cds meter, on the front of the camera, on the 7s does not need to be removed to remove the camera top. |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 56
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 22, 2012 - 04:34 pm: |
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Thomas1,
Thanks so much for the advance notice of what I will find. Funny you mentioned the 2 screws on the back near the sensitivity selector. Someone removed those in the past on my camera and I now know that I will be spending at least an hour on this guy. Anyway, great information and you have certainly saved me a lot of grief.
We'll have to compare notes after cleaning the clutch. Hopefully the noise will go away. Its like you said, the shutter operates fine, but the noise afterward is sooo annoying.
jeff. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 12
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 22, 2012 - 05:52 pm: |
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There is a lever that puts pressure on a bearing fitting into the back of the high low selector. You can see the indentations one at a time in the knob from inside the cover. The size of the bearing is about that of those in rear of the Canon FD, later model lenses, that sometimes cause trouble with the lens. Of course with a magnifying glass you can guage the size if necessary, if the bearing has come out. With the top off my 7s the wires to the meter have been cut out leaving only short ends to trim and solder, just enough if careful, but very little room. You may need to tape together the parts, lever to body inside, on the sensitivity selector to get the screws in with the bearing. Also, some non permanent glue, like paper stick gum that comes in a tube, may hold the bearing in place while attaching the metal lever - the bearing isn't going anywhere. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 14
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 23, 2012 - 07:16 pm: |
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Doc. - Jeff, whoever is interested, I was thinking about the problems with the recent 7s acquisition camera I am working on and wonder, could the situation where the shutter can be released without a full wind occur because the camera had been sitting a long time with the shutter cocked and the grease setting up so the lever responsible for preventing shutter release before fully winding is stuck and this is something a simple cleaning by a soak with solvent will solve. Since the "run on" at slow speed is most likely from a sticking lever then most likely the other problem is the same - so repair is accomplished by cleaning and lubrication, in the winding area and around the shutter release button. I think nothing is broken - just sticking. Just a thought. I am picking up some replacement wiring for powering the Cds meter. I am interested in anyone's thoughts concerning the "rangefinder patch" and how apparent it is - why so important ? - and complaints about contrast. Stick a yellow filter in front of the rangefinder mirror window and what do you know - a beautiful rectangular patch appears - so why not augment internally with filter material?? The Cannon 7's have quite a bit of room and the filter piece could be placed, internally, right in front of the side of the prism block, whatever color you like! I'll let you know how it turns out, maybe even a .jpg. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 15
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 29, 2012 - 05:20 pm: |
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After taking top of 7s off I found that the wiring had been cut off for the meter between the meter and the check/off/ on selector unit. I found that the contacts on the check and on positions were corroded and that a piece of plastic that rotated with the selector switch to put pressure on the contacts had fractured. To fix this I found some small plastic/nylon thick washers and made a replacement which works nicely. This took some heating and filing but without access to parts was almost the only resort. Additionally, the wiring was replaced in segments with heat shrinks to eliminate chance of shorting. The meter works fine now. Only one problem, upon removing the speed selector found that a spring washer which makes the selector and ASA selector move at the same time had been left out by the prior repair person. Do not know a supplier but will check the shop that I use for miscellaneous hard to find items. Also, the T, time exposure setting is giving me problems. Not so important. |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 58
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 31, 2012 - 11:26 am: |
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Funny you'd mention the ASA setting and shutter speed selector not moving together. My 7 has that problem too and I suspect a weak/missing spring. If mine's not missing, I can snap a pic of it so you know what to look for. Repairs are scheduled for some "free time" this weekend, but sometimes my family has other ideas. I'll get to them... |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 16
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 31, 2012 - 09:02 pm: |
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All shutter operations now work nicely including "T", time exposure, as advertised. Fashioned some thin shim metal strip to replace missing spring washer but this only causes fixed position of ASA/DIN which is set at 400/27. When I find a spring washer I will also calibrate the meter which is 1.5 stops optimistic even using a hearing aid battery. May put a diode in the wiring so can use the SR44 battery too, might as well. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 20
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 08, 2012 - 05:09 pm: |
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If anyone ever removes the meter mechanism from the Canon 7s - it is tricky business to re place it in the camera. First I recommend using super glue to get the wires to stay in a fixed position in the bottom of the meter mechanism - where they fit and come out at the sides via some grooves. The original tape simply does not hold them any longer. After a few tries you would see that gluing them in is far better. The meter is grounded to the camera by the two screws holding the meter so if the wires do not fit into the grooves the two screws may not hold the meter flat on the camera body. Careful with the pointer not to bend it upon removal of the meter mechanism. |
Thomas1
Tinkerer
Username: Thomas1
Post Number: 21
Registered: 02-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 08, 2012 - 05:13 pm: |
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After removing the bottom plate of the Canon 7s I found the shutter brake or damper spring installed improperly - no tension on the spring - I do not know if this contributed to the shutter curtain tear but hopefully with a shutter unit replacement - the whole bottom mechanism replacement will have everything right. |
