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

Subject: Re: [OM] OM1-meter problems - chapter 2...
From: T.Clausen@xxxxxxxxxxxx
Date: Thu, 7 Mar 2002 23:57:23 +0100 (CET)
Ahh, well my background in electrical engineering comes in handy ;) I
think I did the "right thing", sorta...

Actually, I've seen too many "seemingly good, but in reality bad"
solderings, so I actually did lift the (what do you call the metal you
melt in english?) to check each resistor out of the circuit board. Then
resoldered with fresh (what do you call the metal you melt, again?)

Hmm...

I was afraid it could be bad cds cells. Wonder if such are locally
available....

Anyways, thanks a ton for your help - again ;)

--thomas

On Thu, 7 Mar 2002, John Hermanson wrote:

> 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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> 
> 
> 
> 
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-- 

-------------------------------------------
  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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