Olympus-OM
[Top] [All Lists]

[OM] Re: ON-2N and battery failure

Subject: [OM] Re: ON-2N and battery failure
From: "PhotoSphere Olympus Camera Service" <olyfix@xxxxxxxxxx>
Date: Tue, 8 Jun 2004 11:59:32 -0500
The meter needle on the OM-2/2n is an indicator ONLY -- it has absolutely no
effect on the actual operation of the camera.  In Auto and Off modes, the
exposure is controlled by the light entering the two photocells on the main
circuit underneath the mirror.  Hence, the meter may be completely dead, but
the camera will still deliver accurate exposures -- you just won't know the
approximate shutter speed to expect.

The battery check is predicated on the assumption that you're using two
silver oxide batteries, not alkaline or lithium substitutes.  Lithium or
alkaline batteries may have enough voltage to activate the battery check
light, but may not have the amperage to properly deflect the meter needle.
In this case, the meter will always read low, and you can expect the shutter
to begin locking up intermittently sometime thereafter.  Still, the battery
check will say "good", so unless you know to use the silver oxide batteries
you might suspect that the camera is malfunctioning when the only problem is
improper batteries.

There are numerous problems that might result in the meter needle being
"jumpy".  The meter switches on some OM-2's were not "gold" plated, which
may result in erratic meter readings, especially as the meter switch is
touched or wiggled.  Or, as noted, the meter wire may be parted within the
insulation ("frayed"), resulting in intermittent connection.  This will
usually manifest itself as the mechanical inputs are varied (aperture, ASA)
for obvious reasons.

Since the OM-2/2n does not allow you to set the shutter speed dial "between
the speeds", there is little need to address meter fluctuations while the
shutter speed dial is turned -- as long as the meter is stable on the speed
being set, there's no effect on the camera's operation.

If the meter needle is always high or low and appears to move in an
unusually animated fashion (as opposed to leisurely or smoothly, as it
should), the problem is likely due to one of the meter coils being "looped"
around one of the balance weights on the frame of the windings.  And if the
meter seems to "hang" now and then, but works fine at other times, there may
be metallic debris on the meter's internal magnet.  This can be a very
frustrating problem, since the debris will "stand up", interfering with the
movement of the frame to which the needle is attached, only to lie down on
occasion allowing the meter to move properly.

After this, there may be cracked resistors, loose ground screws on the
circuit, intermittent short circuits, etc, etc.

Bottom line, in all likelihood, the meter problems may have been totally
unrelated to the camera locking up.  My suggestion is to install two good
silver oxide batteries (if you haven't already), and see what happens.  If
you still get erratic readings, or if the camera locks up when it shouldn't,
it needs work.


>
> > What seems to have happened is that the meter went haywire in some stage
> > of battery failure prior even to the shutter starting to lock up.  Who
> > ever heard of that?
> >
> > Joel W.
> Me.
> IMHO (hope to read more expert diagnostics soon), it's not a battery
failure
> but a meter needle problem, that is on some part of the circuit that
governs
> the needle. Been there, when OM2 were easily repaired here at Mvd. And I
> seem to recall it happened twice to me. Now, she still does a jerky jump
> when on manual setting I pass through 1/8 :-(, but I can live with an
> occasional jerk.
> Can't remember the exact explanation of my technician, sorry.
>
> /F.
>
>
>
> ==============================================
> List usage info:     http://www.zuikoholic.com
> List nannies:        olympusadmin@xxxxxxxxxx
> ==============================================
>


==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz