    
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 35
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 06, 2009 - 03:05 am: | 
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No question, just a report in case it's of use to anyone trawling the archives.
I was resurrecting a Pentax KM with numerous faults and thought I'd finished when I found that the focussing was adrift. Focussing on something six feet away, the standard lens distance scale read only five feet and the camera appeared to focus well beyond infinity. A close look revealed that someone had at some time replaced the mirror. they'd bent the retaining clips at the front and because the glass was loose on the carrier had then bedded it on epoxy adhesive, leaving the mirror a fraction higher than it should have been. (They had obviously realised that something wasn't right, as attempts had been made to adjust the three set screws under the focussing screen, but all they'd succeeded in doing was wrecking the slots.)
The mirror separated from the epoxy easily enough (poor/no keying)leaving the epoxy on the metal mirror carrier. That took some shifting but was done with care, patience and a vacuum cleaner to stop bits of epoxy getting into the works. Tweaking the clips put the tension back into them again and when the mirror slipped back in it was held snugly by the clips at the front and bar at the back of the carrier. Focussing was restored to its proper state. I don't know whether any adhesive would have originally been used, but just to be on the safe side I painted a strip of epoxy along the front edge of the mirror and carrier.
Steve |
