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GEORGE
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 31, 2005 - 08:39 pm: | 
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I HAVE A PROBLEM WITH A PETRI 2.8 COLOR CORRECTED SUPER. THE RF ADJUSTMENT RING ONLY MOVES ABOUT 1/4 OF A INCH, BACK AND FORTH. I HAVE TRIED TO GENTLY PUT PRESSURE ON IT , BUT IT JUST WONT GO ANY FURTHURE. ANY SUGGESTIONS? |
Mike
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 01, 2005 - 11:20 am: |
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Sounds like dried out grease in the helical. Probably the green stuff. Will require removal of the entire lens unit and disassembly to brush out the dried green stuff and replace with new. Most solvents I am aware of won't do a thing to the green stuff. |
Jim Brokaw
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 01, 2005 - 11:26 pm: |
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I had a lens with the dried out green grease, and it yielded to a soaking in a small jar of 99% isopropranol alcohol. Every grease has some kind of solvent, its just a trick to find the right one sometimes. Naptha (Ronsonol) wouldn't touch this green stuff, but the alcohol dissolved it pretty good. The soaking was necessary because I couldn't budge the threads to get them apart to clean. |
Howard
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 02, 2005 - 01:52 am: |
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Hi George.
I have a couple of these Petri's and the grease they use is not the famous Agfa green grease that locks solid. Usually Petri helicals get very stiff but dont lock up in the way you mention. I suspect the problem may be something else. The movement you are getting could be caused by the three? adjustment screws that are located in slots and could be slipping because the helical is locked and someone has forced it. You will probably need to remove the front plate and unfortunately the Petri body is covered in vulcanite that come off in shards, so you will need to re-cover the body when you have finished. I live in Australia and found that a heating stove product call "Shellite" dissolved the grease very easily. Have fun, they are great cameras. |
