Well, with my usual clumsy approach to things mechanical, I took another
swipe at fixing my "free" OM-10. It has worked fine since putting fresh
batteries in (doh!), so the fixups are fairly basic.
1. Oil on the magnet. (sticky shutter release - up to 1 second delay on B!)
Removing the mirror box bottom was quite easy - I taped the mirror up, then
carefully pried the plastic bottom up and out. In the early model, the bottom
is clamped onto two metal pins at each side, and a dab of contact cement
near the rear. The magnet is hidden beneath a flex circuit, which must be
pried away. I used strips of thin card stock dipped in brake cleaner to
degrease the contacts, sliding the paper between the magnet contacts, and
repeating with clean paper 4-5 times. Release the mirror (leaving bottom
cover off for now) and test the shutter for release. Seems good. Test with
manual adapter at 1/1000 in front of TV - pretty good - about 1/4" diagonal
stripe visible.
1a. Repeat above on my newer OM-10, which has a different mirror box
bottom, held in by one "clamp post" and a small philips screw at the rear.
With the shutter on B with locking cable release, my philips driver could not
grip the screwhead through the rear, but a small flathead could just loosen it,
luckily. After this the bottom was much easier to remove than the older
design, and did not use the annoying felt light seals found in the older OM-
10. Better yet, the magnet is near the front, in plain view, so the cleaning
was quick, using same method as before. Again, tested at 1/1000 and it
seemed much better, although still not 100 onsistent.
2. Focus screen and mirror cleaning: The older OM-10 had a mirror and
screen which appeared to have been cleaning with someone's dirty fingers,
so I attacked these next. A Q tip dipped in lens cleaner, then rubbed across
the mirror, starting from the farthest point did the trick. Before it dried, I
wrapped a clean Q tip in some soft lint free cotton, and polished the mirror
gently. Much better!
The same approach on the screen was not so successful. The mirror
cushion foam was starting to rot, so it was hard to avoid getting more black
specks on the screen when cleaning it.
I pried the little crescent moon shaped plastic tab glued just above the mirror
stop at the top of the lens mount area. This covers the aperture sliding
potentiometer circuit (?), and the screw/spring clamp holding the screen in
place. Remove the screw and clamp, carefully easy the screen down, and
remove. I washed it under warm water and detergent, then dried with lint free
cotton again. Replaced screen, only to find that some of the dirt is actually
between the prism and viewfinder window...
But the screen and mirror are now looking quite good, given how they started
out.
It appears there are many changes on the OM-10 between these two
models, with the newer one appearing better in all cases except one: the
bottom plate is plastic; the old one is metal.
The newer OM-10 also has a noticeably larger mirror.
Shawn & Janis Wright
swright@xxxxxxxxx
http://Zuiko.sls.bc.ca/~swright
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