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Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 92
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 21, 2011 - 03:27 pm: | 
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I recently acquired a Nikon F with the early non-TTL finder. Now, it's my understanding that with all the pre-FTN finders one has to set the ASA dial to the maximum aperture of each lens that's mounted. That's certainly the way it is with this one.
The problem is there's some looseness somewhere in the assembly and, as I rotate the shutter speed dial to select another shutter speed, the ASA setting dial will often turn also. I note that the whole dial is spring loaded so that it will sit in a pin that will move an assembly that will rotate the actual shutter speed dial on the camera. I guess it's springloaded so that, regardless what it's set to, when the finder is removed and then replaced, it can easily be aligned to the camera's dial just by rotating it. But there is some looseness up there on the very top.
I would like to dismantle this portion of the dial and see if I can tighten things up, but I've learned from previous mistakes that there is a right way and a wrong way to do things like this. So, I thought I'd ask first about the procedure involved, and if there's anything I need to watch out for. Thanks in advance. |
Old_school
Tinkerer
Username: Old_school
Post Number: 40
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 26, 2011 - 08:10 pm: |
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CT:
Racking the brain a bit as it has been a very long time as to the inner workings on the Nikon F metering heads. I think you can handel them as they are straight forward. The front plate first, leatherette comes off & then the cover to reveal the big wiper resistor gear that the Film speed & shutter speed turns. Just try & scribe a reference mark & take some notes. You should be ok, I do not remember any spring load or anything very complicated on the F or the F2 heads, but the resistors would wear out & cause the needle to jump around. They made some improvements on the F2 resistor ring later in the game. I do not recall working on that specific model that you have as it was already considered out dated & no one I knew serviced them. The thing is I can remember a picture of the F Tn inner rings, but can't remember exactly how it came apart. Don't know if this helps... May besome one else can contribute here & help CT out. |
Old_school
Tinkerer
Username: Old_school
Post Number: 41
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 26, 2011 - 08:19 pm: |
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Oh! You are right on the lens indexing part as the FTN heads did an index when the lens was installed on the camera you would rotate the aperture ring in a full range & it would click in a register on the front of the meter head. As I recall there is a f stop scale window & a red line that indexed the lens max ap. |
Old_school
Tinkerer
Username: Old_school
Post Number: 45
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 27, 2011 - 07:35 pm: |
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CT: M_currie posted this on the slow speed ?
http://arcticwolfs.net/
You should take a look & thanks M_currie.. |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 94
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 28, 2011 - 11:44 pm: |
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Hey Old_school, thanks for the link. Some useful stuff there, but nothing that pertains to my finder. I understand what you're talking about with the FTN finder. It was definitely the handiest to use because the user didn't have to futz with the ASA dial anymore when changing lenses. But my old finder has that ASA dial atop the shutter speed dial. It is my recollection that this was a "feature" of all the metered finders prior to the Photomic FTN finder. Anyway, I'm hoping that there are no surprises when I begin to dismantle this portion of the shutter speed dial. I'll let y'all know how it turns out. |
M_currie
Tinkerer
Username: M_currie
Post Number: 260
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 29, 2011 - 08:28 pm: |
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Early Photomic meters have an ASA dial that turns and holds by friction. When you turn the dial by its outer collar, the inner dial should follow without slipping. Like many such dials, I suspect that it's done by stacking little springs and washers - probably a curly washer in there somewhere, so that when the top nut is socked down, the spring washer holds enough tension to keep the dial from rotating freely. If the top nut gets loose, it might allow one or more washers or springs to move sideways, so that when the nut is retightened, it doesn't push the stack tight, but pushes a washer onto a stepped shaft instead of over it. If that's the case, you might get lucky, and just be able to open it up, note the order everything is stacked in, put it back together very carefully, and tighten it. This is assuming that someone else did not already either open it and lose a piece, or that it did not fall apart at some point and lose a piece. If it's not obvious when you open it up, you may find you have to rethink the order of pieces. And of course if a piece is lost you may have to use your imagination to figure out a fix.
If I do find anything, I'll post back.
Sorry to say, I can find no disassembly info for these. Later TN finders and the FTn, have a different arrangement, in which the ASA is changed with the outer collar, which is toothed. Lift the collar to change, and when the spring pushes it down, it stays. Very effective, but alas, no experimenting on mine will give information for yours. |
Brcamera
Tinkerer
Username: Brcamera
Post Number: 89
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 30, 2011 - 12:13 pm: |
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The ASA dial on the Nikon F Photomic maintains its friction by just a single wavy washer. Once you remove the chrome center hold down screw on the ASA dial, the dial will lift off and you can access the washer. Simple, a bit primitive by today's standards. |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 99
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 05, 2011 - 02:11 pm: |
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Hey thanks for the feedback, guys. I was kinda figuring it was something like this. One more question. Brcamera, you mention the chrome center hold down screw. What looks like a hold down screw on my finder has a small round piece of leatherette right there. I haven't tried peeling it off yet, but I suspect it's covering something that'll let me take off the dial. That or I'll have to attack things from the bottom. The entire knurled chrome knob up there is loose anyway, and I'm thinking this is probably related to the ASA dial moving when not wanted. |
Brcamera
Tinkerer
Username: Brcamera
Post Number: 93
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, June 06, 2011 - 09:38 am: |
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Yes, the small chrome piece on top holds down the dial. You can try to remove the leatherette covering in the center, but on every finder that I have seen, it is very tightly glued down and probably would need destructive removal! I take off this part with a tool that I made from 3/16" tubing and using double stick tape you can remove the cap without damaging the leatherette.
Bill |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 103
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 08, 2011 - 07:08 pm: |
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Thanks for the tip, Bill. I'm not sure I follow the tool you made, but I think I've taken care of the problem. Once you mentioned taking off the part, I took a closer look at that small chrome piece and just began turning it with finger pressure. It was loose and began to unscrew. So I tightened it then with finger pressure and when I couldn't get my finger or thumb to turn it anymore, I used one of those thin rubber mats that you use to remove stuck-on jar lids? Using that, I was able to get the "screw" to tighten just a tad more, but then that was it. Anyway, the slack is gone now and the ASA dial is nice and snug. It stays put now. I love easy fixes! |
Brcamera
Tinkerer
Username: Brcamera
Post Number: 97
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 08, 2011 - 07:24 pm: |
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Glad it worked out smoothly! I love easy fixes too, just seems like they are sometimes far and few between. |
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