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Waynemel
Tinkerer
Username: Waynemel
Post Number: 132
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 10, 2010 - 02:33 pm: | 
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I have un-jammed an FTb, but now have an issue with some of the shutter speeds.
All speeds seem fine except for 1/1000th and 1 second. It seems inconsistant at 1/1000. Some times it seems to open fully (when looking at a light through the shutter) although it does seem dim. Other times it doesn't seem to open at all.
The other strange problem is that 1 second is very short after trying the 1/1000 setting. After firing the shutter on B, the 1s is fine (until it is fired at 1/1000th again).
Any ideas on what may be causing this? |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 236
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 10, 2010 - 02:55 pm: |
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I would first check if the shutter spindle bushings are in good shape. If you notice the bushing have been worn to oval shapes around the spindles, then it is a hopeless case unfortunately. If the bushings are okay, then ...
I suspect it is the shutter spindles. If they haven't been cleaned recently, they might have resistance due to dried lubricants and disuse. That would explain the inconsistent shutter speeds. The unequal travel times of the two shutters due to this problem results in their meeting prematurely (second curtain collides with the first one), called shutter capping.
I would first try dropping one or two tiny droplet of naphtha on the bushings of the four spindles (a pair for each of the two curtains). Let them dry out and then drop a droplet or two of lubricant on them and work the shutter number of times at various speeds. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 134
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 11, 2010 - 09:05 pm: |
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Thanks for the suggestions.
I've tried to clean and lube what I could see. Are all of the spindles and bushings visible?
I've been able to correct the problem with the B setting. I traced it to the smaller (second tallest) follower on the shutter speed selector dial. It must have become slightly bent when I replaced the assembly, and it would not slip into the groove properly. Could the 1/1000th second issue be caused by something similar? |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 244
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 11, 2010 - 09:49 pm: |
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I think one of the bushings is under a white plastic gear. Check the archives, I recall posting a labeled photo showing indicating the spindles of an FTb.
By the follower, do you mean the little cams just below the speed selector dial? If yes, then yup, the arms (there are 3 in all, IIRC) need to be engaging the right cam for proper speeds. Did you take out the mirror box? If not, if you just removed the speed selector, then it is a bit tricky to reseat the arms it but not difficult. I probably posted a labeled photo regarding this as well within the last 6~10 months or so here.
Good luck! |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 135
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 12, 2010 - 06:11 am: |
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I've found the old posts. Great photos and information.
Yes, I was referring to the follower arms on the speed selector dial. I think they are all engaging properly.
What I think I will have to do now is remove the light meter and shutter speed assembly to gain easier access to the top spindle bushings. Once I have made sure they are clean and lubed, I will go from there.
BTW, mine is an older FTb. I have all brass gears and no finicky string for the shutter speeds in the viewfinder. |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 245
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 12, 2010 - 07:47 am: |
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When I cleaned and lubricated the spindles on mine, I did not do the ones under the galvanometer housing. The photos I took after that CLA showed no shutter capping anymore (it was quite severe before that) at any speed. So perhaps those two were not that critical.
However, I shot another roll some weeks ago with it and noticed a bit of capping (an underexposed band of around 2~3% of the image width on the shutter closing side; right hand side of a print). I am going to clean and lube the spindles again and this time might as well do the ones under the galvanometer, but I am not sure how to remove the meter and its housing to access the bushings under it. If you can explain this, it would be great. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 136
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 13, 2010 - 01:22 pm: |
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Thanks for the help.
I have cleaned all spindles on the top and the bottom ones as best I can. I'm a little concerned with the two on the right hand side of the camera (where shutter curtain tension is adjusted). Are they under the cogs? They seem difficult to get to.
Anyway, I'm not sure if the cleaning and lube did it, or the adjustment of the shutter speed assembly, but 1/1000 is looking much better. It still seems a little dim, but it is at least consistant.
I may try to lube the bottom bushings again and check the shutter speed when I have built a shutter speed tester (I'm having trouble locating a phototransistor....but that's a post for another day.) |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 137
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 13, 2010 - 01:25 pm: |
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By the way, removing the meter assembly is very easy. Two screws and it lifts out.
Be careful of the meter needle as you lift it out, it bends easily. |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 247
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 13, 2010 - 03:13 pm: |
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I would wager that the cleaning had a lot to do with your success, but reseating the speed dial definitely is a must. Regarding the cogs that adjust shutter tension, you don't really need to touch the bushing, AFAICT, you just put a tiny droplet of two of naptha at the base of the cogs and capillary action does the rest. Followed by letting it dry and a tiny droplet or two of lubricating oil.
Thanks for the tip on the meter removal. Did you by any chance take photos of the removal process?
Regards. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 138
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 13, 2010 - 05:14 pm: |
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I didn't take any photos. You shouldn't really need them, it's very straight forward. Nothing goes "poing"! Just watch the wires and needle. You will have to remove the rack that goes to the shutter speed dial first.
I think my problem may be related to the shutter speed cogs. There seems to be a copius amount of laquer or whatever was used to keep the cogs from loosening. It is built up around thier bases and is probably preventing alot of the lubrication from getting to where it is needed.
I will try to remove more of the laquer with acetone and lube some more. |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 248
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 13, 2010 - 07:42 pm: |
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I say why don't you try a roll of film in it after what you have already done so far? If it turns out okay, you are good to go!
Yeah, the rack needs to be removed first of course. I have stripped it till that point, the rack and the speed dial, but didn't go further till the galvanometer. I might do this this weekend after your instructions. Whenever I do it, I plan to take pictures :-)
Thanks. |
