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Marty1107
Tinkerer
Username: Marty1107
Post Number: 7
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 08:12 pm: | 
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Hello
I have an SRT101 and at the slower shutter speeds, 1/30 and below, the mirror would not drop down after the shutter was released. If I advanced the film then the mirror would drop down and I could take the next shot. I pulled the bottom off and I noticed that the Mirror Kick Gear would not rotate quite far enough at the slower speeds. I applied a couple of drops or lighter fluid (Ronsonol) to the gear thinking that it might have accumulated a bit of dirt or grim, and within a few minutes the plastic gear had fractured into multiple pieces. Has anyone ever seen this happen on the old plastic gearing in the SRT's or was the gear failing to begin with. Thanks
Martin |
Jon_goodman
Tinkerer
Username: Jon_goodman
Post Number: 18
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 08:40 pm: |
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I've never seen this happen, but the SRT was known to have second curtain lag. In fact I used to hear this question so often, I prepared two annotated images to explain the fix. You can see them on Photo.net, in fact: http://photo.net/classic-cameras-forum/ I saw this question just today.
Good luck.
Jon |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 821
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 08:52 pm: |
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ouch! i don't know offhand of any plastics that would be affected in that way by lighter fluid, so my assumption would be that the gear was stress cracked already.... but I have to admit that the gear crumbling immediately after the solvent exposure sounds an awful lot like a chemical attack. This is exactly what happens if you put brake cleaner on polycarbonate when it's under stress. But gears are seldom made of polycarbonate, the usual material is nylon (which is very chemical resistant) or delrin (which is even more so), and Ronsonol is a vastly less aggressive solvent than brake cleaner, at least from the point of view of the plastic. |
Jon_goodman
Tinkerer
Username: Jon_goodman
Post Number: 19
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 09:17 pm: |
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PS...look under "what temperature is too cold for a classic" at the photo.net site.
Jon
I agree with Rick. Naphtha is much less aggressive. |
Bossman
Tinkerer
Username: Bossman
Post Number: 13
Registered: 02-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 11:07 pm: |
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I have no doubt put a few drops of naptha or Coleman fuel on at least 1000 SRT gears and other parts and NEVER had anything to disintegrate like your gear did. One adjustment that most SRT's need to get up to standards is to increase the tension on the second curtain (the adj'mt closest to the front of camera is the 2nd curtain adj'mt, counterclockwise to increase tension). |
Mndean
Tinkerer
Username: Mndean
Post Number: 126
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 11:11 pm: |
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The mirror kick gear shattering is a new one on me as well. I've a half-dozen SRT cameras and not a one had that happen. Someone out at the auction site used to sell a replacement gear made out of metal and may still, but consider if it's worth it to you before going that route. If I weren't so busy at the moment, I tear my 303b parts camera apart and send you the gear. Unfortunately I haven't even been able to shoot at all this past 6 months, let alone do any camera teardowns, which a couple need badly. |
Bossman
Tinkerer
Username: Bossman
Post Number: 15
Registered: 02-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2009 - 11:32 pm: |
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Marty: Send me your address and I'll send you one of the gears you need N/C. I have about 15 SRT's for parts. Art, [email protected] |
Marty1107
Tinkerer
Username: Marty1107
Post Number: 8
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 01, 2009 - 04:36 pm: |
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Hello - Some additional information. I've notice that most gears are white, black, or blue (newer X370/570/700). This gear is yellowish in color so is it possible that it's neither nylon or delrin?
Art - The gear pieces will go out in the mail in the morning assuming I can get to the mail box. The snows are coming down.
Martin |
