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Bossman
Tinkerer
Username: Bossman
Post Number: 119
Registered: 02-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 05, 2010 - 10:32 am: | 
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Anyone out there know how to get to the front element assy so I can clean for fungus spots? Turning out the usual name/ser ring is not the way as it stops after a couple turns. HELP? |
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 56
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 08, 2010 - 08:50 am: |
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Hi,
I posted a similar request for assistance on this same lens for the same reason a couple of years ago. I drew a total blank. Presumably as it's a fairly unusual lens there won't be that many people here with experience of it. Also, as it's a pricey lens, perhaps some who might have dismantled cheaper SMC's will have sent their f1.2 to a professional repairer.
I initially thought that my problems unscrewing the name ring were because the filter ring had a slight ding in it. I straightened that out but still couldn't shift it more than a couple of turns, so went a bit further and drilled two holes for a bit more purchase, but still no luck. It seems that the diameter of the name ring thread is greater than that of the filter thread. On my lens there's a small step in the profile of the outer surface a few mm back from the end of the front element assembly, so I tried unscrewing that, again with no success. I'm still not sure whether that's a separate piece on the front of the body or whether it's just a machining operation for some reason.
I also looked under the rubber focus grip and investigated going in from the back of the lens, but with no success. Having run out of ideas, I've given up and mothballed the lens until some further information or ideas come along. I accept that I may croak it before this happens!
Good luck, and please let me know how you get on. Incidentally, a camera repairer who I respect did once look at the lens before I straightened the filter ring and tried (and gave up) unscrewing the name ring with the usual rubber cup. he couldn't get it to move at all, but clearly thought it came out in the usual way. again, he may not have seen many f1.2s.
Cheers,
Steve |
Bossman
Tinkerer
Username: Bossman
Post Number: 121
Registered: 02-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 08, 2010 - 11:02 am: |
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Steve: Gosh, thank you for taking so much time on this post!! I AM a professional (at least I thought so!!) camrea repairman with over 45 years experience but this one has me baffled. I actually did all the SAME things you mentioned above and got nowhere!! Always hate to give up on a repair that SHOULD be simple but I guess I have to cut my losses and send it back to the customer a failure. I did however repair his Retina IIIC, first one I have done in 10 years so.................. a .500 batting average tops even Ted Williams!! Thanks again Sir!! |
Barnum
Tinkerer
Username: Barnum
Post Number: 185
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 08, 2010 - 12:15 pm: |
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Hello Art.
I am Barnum,(nee Roger), & was interested to learn of your experience in camera repair. Hopefully you will not mind my taking advantage to ask the following...
Do you have a mine of camera parts? If so, I will send a SHORT list.
Assuming you would be willing, how much to fix the slow speeds on a Robot 2?
Do you do replacement bellows? I have an Instantagraph here that some GREAT TWIT put next to a radiator,(not me)!
Kind regards,
Roger |
Camman60
Tinkerer
Username: Camman60
Post Number: 1
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 08, 2010 - 04:40 pm: |
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Hi,
I had the same problem a few years ago and if I remember correctly the filter ring/name ring are held onto the lens by three small set screws. The filter ring and name ring come off as a unit and the name ring does not unscrew like you would normally do to access the front element. If you set the focus on the lens to minimum focus (fully extended) you may see the 3 set screws that retain the filter ring. I don't recall if I was able to loosen them at that point or if the front part of the focus ring had to be removed. If you have to remove the focus ring front I believe you have to remove the rubber focus ring grip and then the tape that holds the front and rear together. Again my memory is a little fuzzy with age as to exactly how to access the set screws but if you look closely you should be able to see them and figure out how to access them. Well worth saving that lens. Its a good one!
Kelly |
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 57
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 09, 2010 - 02:24 am: |
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Art,
Well, it's good to know that even as a total amateur I followed the same steps as a professional! Thanks for your response, Kelly - I'll go home and have another look. This lens is something of a Chinese puzzle compared to other SMCs, but the bottom line is that someone put it together, so it must be possible to take it apart. As my lens is my own and not a customer's, I may be inclined to investigate a bit further than you, Art, so if you want to give me a few days I'll have another go equipped with Kelly's information and let you know how I get on.
best wishes,
Steve |
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 58
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 29, 2010 - 09:32 am: |
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Well, I've had another go and I'm none the wiser. Couldn't find any set screws - in fact nothing to reveal how the lens comes apart. My sneaking suspicion is still that the very end rebated piece into which you screw filters is itself screwed into the lens body. looking with a magnifying glass, I think I can see the start of a thread, but I'm not sure and if it is, I can't move it. Any further ideas, please, anyone?
Steve |
Brcamera
Tinkerer
Username: Brcamera
Post Number: 62
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 29, 2010 - 10:47 pm: |
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Although I have not had this particular lens on my bench for repair, here is a page from the microfiche parts manual on the lens, maybe helpful?
http://billrogers.com/images/38102.jpg |
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 59
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 01, 2010 - 02:28 am: |
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Thanks very much, Bill. That diagram does indeed look helpful. For starters, I can see what I take to be the three set screws referred to by Kelly three posts above. I'll go back and keep worrying away at it!
Best wishes,
Steve |
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 60
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 04, 2011 - 06:51 am: |
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Mystery solved!!! Well, I needed to escape from the endless round of cold turkey and Christmas pudding over the last week and so had yet another crack at the Pentax f1.2 From the diagram kindly supplied by Bill and Kelly's info regarding the three set screws, it was apparent that they were indeed concealed by the focussing ring. However, it's only the very front lip of the focussing ring (ie the lip that keeps the rubber grip from slipping off to the front) that unscrews. this is X18 in Bill's diagram. It's so thin that I couldn't grip it reliably and so filed two small 1mm width slots at 180 degs in it and made up a key to locate in those. I clamped the key in a vice, held the lens in place and gripping the focus ring by hand, the front lip relatively easily unscrewed (conventional thread)from the larger part of the focus ring X17. You then need to set the lens to closest focus (as per Kelly's message) for the three screws to be exposed, and even then they are only just accessible. Removing them allows the barrel/filter ring assy. X14 to be removed and then away you go.
I have some minor damage from earlier unsuccessful attempts at disassembly to make good, but I'll know better next time and hopefully so will anyone else who needs to take one of these things apart. Thanks to all who helped and good luck to Bossman - if your customer hasn't had any joy elsewhere perhaps you can still help him out!
Best wishes,
Steve |
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