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Re: [OM] OM1-meter problems - chapter 2...

Subject: Re: [OM] OM1-meter problems - chapter 2...
From: "John Hermanson" <omtech@xxxxxxxxx>
Date: Thu, 7 Mar 2002 16:25:19 -0500
Since the resistors are in parallel with the cds, you'd have to unsolder one
end of each resistor to read them accurately.  When you say you checked the
soldering, I assume that means you reheated all the solder joints.  Could be
bad cds cells.
_________________________________
John Hermanson  www.zuiko.com
Camtech, Olympus Sales & Service since 1977
New OM & Used, Digital, Pearlcorders, Binoculars
21 South Lane, Huntington NY 11743-4714
631-424-2121
_________________________________
----- Original Message -----
From: <T.Clausen@xxxxxxxxxxxx>
To: "Zuikoholics Anonymous" <olympus@xxxxxxxxxxxxxxx>
Sent: Thursday, March 07, 2002 3:27 PM
Subject: [OM] OM1-meter problems - chapter 2...


Hiya all,

I got lot of great advices, and now I've had time to try out some of
them.....

So here's what I tried:

- Asa dial at 100, shutter at B, mount 50/1.8 at 1.8: needle
  centered.

- Resistance between meter frame and body: 0 Ohm

- Resistance "through" the meter (blue wire - frame): 1487 Ohm

- Resistance between the "battery tap" and the brown wire: 0 Ohm

All this seemed good. What I then did was:

- check the ground screw, as Clint, John, Mark et. al
  suggested (unscrew, scratch, tighten...)

- checked all the solderings on the little circuit board
  (resoldered).

- checked the three resistors. From left to right, they are:
  R1= 6.9 KOhm, R2= 8.3 KOhm, R3= 14.1 KOhm. None seemed broken.

Sadly, the result is the same - almost. At 1/8s, f1.8, 100ASA, I can
make the needle center when I point the camera directly towards a
lightbulb. Not good ;(

Anyways, other than the generic "Anyone knows what could be wrong?"
(looking for the quick solution, huh?), I am puzzled: the measured values
of the resistors do not correspond quite to those I see in the schematics
of the metering circuits (in particular, R1 seems off) - and not atall to
the resistance indicated by the color codes. Is this normal?

Secondly (and this is a much more trivial question): the foam below the
hotshoe plug had turned into sticky goo. Any domestic products that are
good as replacement? ;)

Thanks again for all kind advice. It's quite fun, but also getting a
tiny bit frustrating...

--

-------------------------------------------
  Thomas Heide Clausen
  Civilingeniør i Datateknik (cand.polyt)
  M.Sc in Computer Engineering

  E-Mail: T.Clausen@xxxxxxxxxxxx
  WWW:    http://www.cs.auc.dk/~voop
-------------------------------------------


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