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Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 08:36 am: | 
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Chaps,
Peter and Winfried and Rick kindly put me on the right road with an earlier problem I'd had with a sticky Prontor-SV shutter on an Ikonta (oil/dirt on the shutter blades affecting speeds). Can I call again on your collective wisdoms and good natures?
I've tried the 'short' method of bathing the shutter in naptha overnight, and it appeared to do the trick. Next day, after it dried out, it stuck once then was free for the rest of the day. Leave it a few hours more, it may stick once, then immediately be 'free' for ages. So I suspect I may need to go down the more difficult "remove the blades" route Rick mentioned.
I didn't want to do this without some experience on a 'junk' shutter, so I've taken an old Prontor-S shutter from a junker, with the intention of trying the procedure on this one, for practice. (It itself sort of works, but 1s takes 2s, 1/2 takes 1s etc. so I've nothing to lose really.) I've followed the recommended procedure on Daniel Mitchell's site for disassembling the Prontor-SV, and have got as far as removing the speed governor: two screws out and it popped out. The procedure next says remove blade-closing spring. Done. Next, remove the screw in the delayed action device cocking lever. Here I've stalled: on the Prontor-S, I can't see any screw in the DA device. So I skipped this step. Then I turned over the shutter as per instructions, looking to get to the blades, and removed the four screws at the back by adjusting the diaphragm control until they were visible. The procedure then says "pull the two halves of the shutter apart".
Nothing's coming apart, and I'm too nervous to apply silly amounts of force. Are there still screws in the front end of the shutter assembly I need to remove? I've been taking digital pictures of each stage as I go along, but I don't want to start unscrewing things willy-nilly in case I do something that will take six months to undo! There's about half a dozen screws I can see with all sorts of tiny hair springs that look like they'd be the punishment from hell to try and fit back together. |
Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 08:51 am: |
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I feel such an idiot. I was pulling on the wrong bits. The two halves have come apart properly and I can see the blades! |
Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 08:51 am: |
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I feel such an idiot. I was pulling on the wrong bits. The two halves have come apart properly and I can see the blades! |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 10:34 am: |
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Happy we could be so much help!
Getting it back together, the dicey bits are keeping the blades where they belong and getting any odd loose spring ends back into their proper places as you reassemble. The slow speeds are probably a function of dirt in the escapement, and should run better when you're finished. You'll have to watch the adjustment though, as it's established by the position of the escapement assembly on its little slotted holes.
: ) = |
Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 06:36 pm: |
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I almost got there with my practice-run Prontor-S!
I got the blades off, cleaned them carefully, cleaned the escapement, put everything back together, and it was beautiful. Actually, it was exhilarating. The 1s speed went from sluggish 2s back to a proper 1s, the blades were snappy, it was just amazing, and it looked brand new. It's the first time I've ever done anything this complex (I'm not naturally dextrous) and I got a real electric buzz from it that's hard to put into words.
I put the cover disk back on, checked that the shutter speed marks were settled in and giving a sensible 1,2,5,10.... progression, which they were. I put the scalloped ring back on, and tried a few more trips of the shutter just to check all was well. At that point, I noticed the shutter blades had stopped opening. What a sinking feeling. I disassembled again, and I think, though I'm not sure, I know what the problem may be. The shutter cocking lever is connected to another lever with a notch in it, which engages with a pin connected to the ring on which the blades are attached, and when the shutter trips, the lever with the notch pushes on the pin which in turn opens the diaphragm then closes it as it returns. This notched lever, however, is hanging loose and it looks as if it should be under some tension, because when cocking the shutter lever, it's not 'mating' into the pin that moves the diaphragm. If I squint closely at the underside of this notched lever, I can see a tiny stud where a wire under tension might rest in order to ensure that the notch is always pressing against that pin. I hope I'm explaining myself well enough here.
Although it was a junk Prontor-S shutter, I was so elated at getting it back into working order that I'm now wanting to know what I can do to get this last bit in place, or if it's a lost cause. I can't see anything spring-like that's fallen out (I took care to work inside a big upturned plastic box lid so that nothing would roll unseen off the table). It was definitely working as I put the shutter speed ring back on, so I guess it's possible something has just given way and broken. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 08, 2005 - 03:33 am: |
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I think you have run across a problem with the internal shutter release levers and/or the B setting lever. Actually it is hard to figure out how they should be arranged once something (a lever, holding screw or hair spring) is missing. It is even more difficult with the later Pronto/Prontor/Vario shutters.
In case I have a Prontor S lying around (I faintly remember I should have one) I can send you some pics of the proper working arrangement.
However, disassembling an older Prontor shutter is not a bad start to shutter tinkering. Most japanese shutters (especially some early ones which are close copies) basically follow the design of the Prontor shutters. |
Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 08, 2005 - 08:04 am: |
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That would be very helpful, thank you!
There definitely seems to be a hairspring missing or snapped, because I can see a remnant around a tiny spindle, and I might be able to form a replacement from some thin guitar wire (at last, one single reason to be glad my son has taken up the guitar!). |
rick
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 08, 2005 - 08:21 am: |
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One other tip... when you put the scalloped ring back on, if you turn it too tight it can cause the shutter to hang or run roughly. if this happens, back it off until the shutter runs smoothly and then secure it in place. that ring is capable of exerting quite a bit of force on the front panel, and all it wants to do is to hold the panel in place.
: ) = |
Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 08, 2005 - 06:56 pm: |
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I'll be sure to be careful, Rick. I think (touch wood) I've got it back working again, though I haven't put the escapement assembly or the blades back on yet. I found there was a hairspring with one of the 'legs' missing, leaving a small lever to swing free instead of engaging with the pin that's on the ring that holds the blades, and the lever was popping off the pin instead of pushing it to open the shutter.
Yesterday and today I've been at it for eight hours in total, that's eight hours solid, not just a period of intermittent work. It took me almost all of that time to fashion a tiny hairspring from guitar string wire, which kept kinking and misbehaving, and sometimes I got so frustrated that I wanted to throw the whole thing out of the window. Somehow, I managed to get something in place just after 1am (GMT) and it worked! I'd had to take off quite a few screws and levers and rockers and hairsprings just to get access, and it took three solid hours to get the makeshift hairspring in place. This might have been only forty minutes work to a camera technician but to me it's been a marathon and the finickiest piece of handiwork I've ever undertaken. When, at last, it finally worked, the sense of elation was amazing, I loved it!
It was only a junk shutter from a junk Isolette I picked up solely for practising on anyway, but it's been an fantastic learning experience, and quite remarkably satisfying. I've also learned a greater respect for the work that has gone in to designing and making these things. I think I'm hooked. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 09, 2005 - 09:09 am: |
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BTW I found that Prontor-S shutter. It currently bears a lens but I am probably going to use it as a replacement for a broken shutter on a Petri 6x4.5 rangefinder so it will be no problem to take off the front plate. |
rick
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 09, 2005 - 12:44 pm: |
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8 hours to repair a shutter may seem a long time... but 8 hours to learn how to repair a shutter is very good progress! and you've encountered and dealt with issues beyond the routine repair. congratulations!
: ) = |
henry
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 10, 2005 - 11:26 am: |
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Yep Alex, that's how I felt after the first camera I ever fixed. It was several years ago. I bought a Demi S off ebay. Seller claimed it worked...we all are familair with ebay sellers now. :-) It really didn't do anything it was so jammed up. But for US$5 or 6 bucks (cameras were cheaper on ebay back then) it looked like fun to just take apart. So I gave a positive, with a minor non-working note, and went my way. Bet I worked on it two weeks! But finally it was totally functional. I even took it on vacation that summer. Those Demi's take fantastic photos.
All excited I thought I'd do it again and bought a non-working Canonet QL17 Glll off ebay. It arrived totally functioning. We all now know ebay sellers! There's no telling what you're going to get.
Henry |
Alex
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 11, 2005 - 03:06 pm: |
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Ebayspeak is a language we definitely need to learn to be aware of. Most of my Ebay experiences have been good, but I've also been misled and, on more than one occasion, deliberately lied to. I learned that 'no battery to test' means 'I know it doesn't work but I don't want to say that' - one Yashica 230AF camera bought that way was dead on arrival, and though the seller eventually took it back (at my expense), he was reluctant and surly about it, then tried to sell me, off-auction, a 270AF instead, saying it had a battery and it did work. Uh. The 270AF and the 230AF take the same battery, so he did have a battery to test. At the other end of the spectrum, I picked up an old Agfa with a good Compur shutter and Solinar lens for a song. The seller again was 'economical with the truth' (lied about condition, lied about it being lost in the post, lied about the date of sending a second he just happened to have, like I couldn't read postmarks, and saw that the lens on the 'dupicate' had the same serial number as the camera in the original auction picture....) - but a little TLC from the tips and advice on this forum had it back to superb working condition, and the lens as crystal clear as the day it was made. I like my modern electronic cameras too, but I could never fix one if it packed up. At least with these old classics, I have a chance of doing something or cannibalising parts for it. And as we know here, it's very satisfying when it works. |
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