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Re: Undelivered Mail Returned to Sender
Michael,
I worry a little that your flaps will not fully uncover the opening. Note
that the message bounced so that I am sending the reply to the list as a test.
You might add this to the service notes section:
The shutters are designed to be self adjusting. They bang against the stop
when full open, and against each other when full closed. The drive is
designed to move more than they can move, so every cycle is supposed to
readjust the shutter.
I say "supposed" because if the shutter takes more force to move than the
pulley friction provides, then it will slip at the point it sticks.
For example, if while closing, the shutter sticks in the track, then the
shutter will not fully close. When it next opens, it will then try to move
a lot more than it can and bang against the stop. The drive pulley now
slips, and this results in it repositioning so that it should more than
close if the track is not sticky.
The problem is, that the shutters were made thicker than they should be for
free running.
To fix, I just take them out and file down the edges of the shutters where
they run in the channel. There is one and one half turns around the
pulley. To remove the shutters carefully note how they are sturung. Note
the string wraps around one tube each side and freely runs through the
other. You can adjust where the shutters meet by loosening the wrap around
and repositioning.
I have been learning how to make the shutters move freely. In general, I
remove the shutter plates and file them down where the slide in the channel
to make them mover more freely. Then I round the corners of the shutter
plates to reduce the chance that they might "dig in". I then replace the
shutters and use graphite lubricant on the ways. You can move the shutters
back and forth by hand to test for free running.
I do this first with the string unwrapped from the servo motor. Just pull
the strings back and forth to check that the ways are moving freely. When
this seems OK, I wrap the string the 1 and 1/2 turns around the servo motor
and gently move the moror back and forth to test that the shutter works as
it should.
Last check is to run the shutter exercise program while looking down the
lens barrel. You should be able to see the shutter fully close and open.
Tom Droege
At 04:58 PM 1/21/02 -0500, you wrote:
>This is the Postfix program at host mail.isp-service.com.
>
>I'm sorry to have to inform you that the message returned
>below could not be delivered to one or more destinations.
>
>For further assistance, please send mail to <postmaster>
>
>If you do so, please include this problem report. You can
>delete your own text from the message returned below.
>
> The Postfix program
>
><alanmccright@tryi.com>: unknown user: "alanmccright@tryi.com"
>Reporting-MTA: dns; mail.isp-service.com
>Arrival-Date: Mon, 21 Jan 2002 16:58:16 -0500 (EST)
>
>Final-Recipient: rfc822; alanmccright@tryi.com
>Action: failed
>Status: 5.0.0
>Diagnostic-Code: X-Postfix; unknown user: "alanmccright@tryi.com"
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>Date: Mon, 21 Jan 2002 17:10:34 -0500
>From: Stupendous Man <richmond@a188-l009.rit.edu>
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>Subject: small progress at RIT
>Sender: owner-tass@listserv.wwa.com
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>
> [Tom, I saw "Test #3", and am stimulated to emit this message]
>
> Over the weekend, I took the cameras off the Mark IV in Rochester
>and noticed that the shutters don't quite close all the way. It appears
>to me to a function of the design -- there's a hard stop into which
>the shutters move when they open, and the stop causes the shutters
>to slide slightly along the strings that drive them. This displaces
>the shutters from their proper position, leading to a small gap
>between the leaves when they return to the "closed" position.
>
> So, I tried fixing it by constructing small flaps from black
>construction paper and affixing them to one leaf of each camera's shutter.
>The flap sticks out and over the edge of the leaf, far enough to cover
>the gap between the leaves. My second try at flaps appears to have
>worked reasonably well.
>
> I need the flaps because I am going to do some flatfield tests
>with light boxes built by one of my students. Without good darks,
>I can't make good flats.
>
> More when I manage to use the light boxes. Mark Teseny built them
>over Christmas vacation. They look very nice, with adjustable lights
>and several layers of diffuser.
>
> Michael Richmond