There are NO VR's in the OM-2/2n METER. The VR's you see are on the
main circuit, and are used to adjust the reference voltages and timing
circuits for the exposure control circuit -- that has nothing to do with
the meter. The only other VR is the ASA input, which is also connected
to the main circuit -- the meter's ASA input is strictly mechanical.
Another interesting note -- the battery check circuit on the OM-2/2n has
no adjustments either!
C.H.Ling wrote:
>
> But I found there was lot of OM-1(n) meter need calibration, the
> position do shift after time, could be there were some impact or shock
> that change the position. I know VR is bad, we made electronic
> ballast, in some circuits there is a adjustment resistor needed, we
> select the right one and put a fix resistor on each board. But I just
> want to say there are many ways for adjustment, you can't avoid it,
> some are better than the other but nothing perfect. Inside the OM2n
> there are at least three VRs, so the quote about no VR adjustment on
> OM1 and OM2 was wrong.
>
> C.H.Ling
>
> clintonr@xxxxxxxxxxxxxxxx wrote:
> >
> > C.H.Ling wrote:
> >
> > > My be the OM1 does not have a variable resistor for meter adjust, but
> > > it adjust the meter mechanically by rotating of the galvanometer, does
> > > it make the adjustment more accurate?
> >
> > Not necessarily more accurate, but probably more reliable -- the
> > coupling mechanism won't wear or change to any appreciable degree, nor
> > will the resistors used to compensate the meter, so it will function
> > accurately until something breaks (or you can't get the proper battery!
> > ;^) In my experience, if there's a variable resistor, it's there
> > because you'll need to change it! If it's not there, you won't need
> > it! And input VR's (like on the OM-2s ASA dial) are notorious for
> > becoming unreliable. For my money, simpler is better.
> >
>
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