Caution: Long post...
A while back Justin Morrison wrote the list inguiring as to the
availability of a focusing screen for his OM-G. The previous owner had
managed to scratch it badly trying to remove it for cleaning.
Months ago I had bought a broken OM-G (*supposedly* a sticky shutter)
for purposes of teaching myself a bit of home OM camera repair.
Justin's plight inspired me to dig out the old OM-G and see if I could
figure out how to remove the screen (amongst other things). Figured if
I screwed it up it wouldn't matter and if I didn't then I could advise
Justin and others how to do it. So, here is a slightly abbreviated
version of the note I sent Justin:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to get the screen out:
The black, semi-circular, plastic piece just inside the bayonet mount
must be removed to reveal the front, screen retaining clip underneath.
(It is glued on with a contact-like cement) The retaining clip is "L"
shaped and the mounting screw is immediately behind the plastic piece.
I was concerned that the plastic piece was also "L" shaped like the
retaining clip but that is not the case. What you see looking at that
plastic piece is all there is.
When the camera is assembled at the factory the sequence must be:
- insert screen
- attach retaining clip with screw
- glue on plastic piece inside bayonet mount
- glue the foam bumper over the top of the retaining clip and the
very edge of the plastic piece
When you try to pry off the plastic piece you will see the foam bumper
starts to move with it because the foam is glued on at the very edge.
That's why I thought the plastic piece was "L" shaped also. I was
concerned that it wrapped around under the foam and that if I applied
too much pressure it would break.
The plastic piece has locating pins that serve to position it. When you
pry it off use a tiny flat blade as a lever and work it around the
outside edge such that you are lifting up. The plastic is not very
thick or strong so work slowly and gradually all along the edge to avoid
breaking it.
You will need a #0 phillips screw driver to remove the retaining clip
screw. It was in very tight so be careful not to strip the head. The
screw is only about 2mm long so also be very careful not to lose it (I
was being careful but still almost lost it). I already had some
jeweler's screw drivers but I went to Radio Shack yesterday and bought a
larger set for $10.99. Glad I did since some of the tiniest flat bladed
screw drivers (1/32 and 3/64) were useful as prying and lifting tools.
I did not remove the foam bumper but may have to eventually. Since the
foam is glued to the retaining clip you still can't move the clip once
the screw is removed. I used a sharp Exacto knife and worked it down
between the clip and the foam until the clip was free of the glue. I
then used two tiny flat bladed screwdrivers on opposite sides of the
clip to lever it out from under the foam. I didn't pull it all the way
out... just enough to clear the screen. The screen did not want to fall
out by itself so I had to encourage it by catching it's corner edge with
the 1/32 screwdriver. A needle would probably also work well there...
but be careful with any metal edge or point near that plastic... it's
really easy to slip.
Anyhow, there's the saga. Putting it all back will be a bit more
difficult; especially if that foam strip has to be replaced. That may
require buying some material from the likes of Micro Tools who sell
camera repair tools and supplies (www.micro-tools.com). On the other
hand maybe it will be reusable if carefully removed.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Having accomplished that, I was encouraged to see what else I could tear
apart so I set about removing the top and bottom covers. Whatever ailed
this camera may have included a session with the cat in the closet most
recently mentioned by John H. There were blue and white powdery spots
on the top and bottom covers reminding me of battery acid. A few of the
screws were also rusty. Getting them out was difficult but I managed
without stripping the screw heads or destroying anything.
A big surprise was finding the aforementioned blue and white powder all
around the inside of the cover seams both top and bottom. I was certain
that I would find the inner works a total disaster. Much to my surprise
all the inner mechanics, electronics and optics (while not necessarily
working) were clean as a whistle.
Apart from the rusty screws, getting the bottom cover off is simple.
Just remove the screws and wiggle the cover off. Getting the top cover
off is a bit more difficult but not hard. If you have Thomas Tomosy's
books on camera repair the OM-G cover removal is almost the same as the
OM-10 which he covers in book 2.
I first loosened all the cover screws slightly just to be sure I could
get them out. Four of the six were corroded and required lots of
patience, pressure and a few light hammer taps.
Next comes the rewind knob. *First*, open the back and *don't* close it
because you're about to remove part of the release catch. Insert a
blade in the bottom of the slotted rewind shaft to hold it still then
remove the screw under the rewind handle. Slide the shaft down till
it's flush with the top but don't pull it out.
Next to the film advance lever. Pull the lever out halfway and remove
the screw on the underside. Lift off the black plastic covering the
metal lever. This will reveal a screw holding the advance lever to the
shaft. Remove the screw and the lever.
Next to the ASA dial. In the OM-10 the dial is attached to the cover
and keyed to the mechanism underneath so nothing has to be done here, it
just comes off with the cover. In the OM-G the dial portion above the
cover is screwed to the mechanism underneath. Turn the dial to ASA 100
and remember where you've set it. Note that the inner part of the dial
with the compensation markings is actually a snap-in cap to the knob
underneath. Look carefully and you will see the seam all around about
1mm from the edge. Using a very tiny blade (the 1/64" screwdriver came
in handy here) inserted into the seam, lift the compensation dial off
the ASA knob. With the dial at ASA 100 I inserted the blade at the
index mark and the cap popped off easily. Note that the cap has two
tiny plastic ears. Note that the knob has indentations for these ears
and will not want to stay on unless put on exactly as it came off.
Under the cap is a screw. Remove the screw, the spring underneath it
and then lift off the ASA knob.
Remove the screws and the cover can now be slid upwards and off. Don't
pull it too far since there are a couple of wires running to the hot
shoe. Also, be careful not to lose the door latch spring. The spring
is located at the 10 o'clock position relative to the rewind shaft and
is held in place by the cover. Removing the cover will allow it to fall
out.
There you have it; partial OM-G disassembly. Next is to figure out why,
at *any* shutter speed setting, the thing is clicking off from 2-4 ms.
On B, if light can get to the sensor, it acts as B should with the
shutter opening and closing with pressing and releasing the shutter
button. Now the strange part. While still on B, if the sensor is
completely blocked (lens cap on), releasing the shutter button does not
close the shutter... it goes on to make an apparently timed exposure of
several seconds. Now it gets wierder. If I change the ASA dial the
apparently timed exposure gets longer or shorter according to the ASA
setting.
So, something of the electronic timing is still working but it's
apparently confused as to what mode it's in. I cleaned and adjusted the
wiper contacts under the mode switch but that had no effect at all. The
ASA dial apparently does something so next is on to the contacts for the
shutter speed dial.
Wish me luck, I haven't destroyed it so far. :)
Chuck Norcutt
Woburn, Massachusetts
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|