In 21 years of doing 1/1N meter repairs, I have had to fiddle with the
separate resistors less the a half dozen times. You'll need a decade box if
you insist, but you're either 1) asking for trouble or 2) the cds cells are
whats throwing your meter off in the first place. You should know that if
you change 1 resistor in the meter board, you'll have to change all of them
to compensate for that change.
There are also galvanometer defects which cause meter error, more often
than "inaccurate" resistors.
John
----- Original Message -----
From: <HI100@xxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Saturday, May 08, 1999 9:37 AM
Subject: [OM] OM-1/1N Meter accuracy
> Hi All,
> After some list membrs had asked for OM1 meter calibration
> information I checked the OM1 service manual and discovered the
calibration
> spec allows errors of up to 0.6EV! In fact the allowable repeatability
after
> changing aperture/speed settings due to slack in mechanical coupling is
> 0.3EV. I would guess as in many spec's this is to allow them lots of
wiggle
> room and that accuracy is typically much better than this after a
> calibration.
> If anybody really wants to try to recalibrate their meters (not
> recommended unless you are very confident of your technical ability) mail
me
> of list and I will send you a pdf file I made up with meter
schematic,layout
> and a cleaned up description of the service manual cal procedure. You will
> have to set up a make shift diffused light source and have a known
accurate
> meter or camera to set up cal EV values with. Since calibration involves
> selecting resistors and substituting parts by soldering it requires a
> reasonable electronic skill level.
>
> Tim Hughes
> Hi100@xxxxxxx
>
> < 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 >
>
< 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 >
|