[R-390] Meter Meister?

[Joe Foley]

--- Gene Beckwith <jtone@sssnet.com> wrote:
> Barry,
> 
> Excellent post...and a frustrating subject for the
> casual meter repairman...
> 
> Agree with ur assessment that sounds like
> pointer/vane is somehow out of
> alignment...but the blowing technique is a good
> test...also have used a very
> thin/narrow bit of paper to "Gently" touch, or prod
> the movement to check for
> rubbing or scraping.  Btw...have found that on some
> "Hamfest" specials...that
> the glass has worked loose and has pushed the
> pointer back against the
> scale...sometimes, the glass doesn't look like it
> moved, but has been pushed in
> enough to cramp the pointer...and stay jammed so the
> glass doesn't
> "rattle...just another check Joe...but sure you
> thought of this one...it's easy
> to fix...but again am sure u check this one because
> it's a classic...
> 
> Now...further questions...
> 
> Barry  . . . Do you have any pet suggestions
> regarding tools, and handling
> techniques for these ultra delicate
> manipulations....I've used the "blowing"
> technique to check for free movement,  bits of paper
> cut to small manipulators,
> re-machined nut drivers to reduce over-all od...and
> re shaped screw drivers of
> various breeds...and types...
> 
> In some cases I've had great success, but in
> others...seems the most common
> meter repair problem has been an "apparently" open
> coil...yuk...not a good
> situation...and have not had luck solving that
> one...even with resoldering micro
> joints...so I assume in these cases, it must be open
> some place I can't isolate
> other than the coil...
> 
> Just ramblings, but meter info always of interest...
> 
> 73,
++++++++
Update, so far,

This meter is in a 5 3/4" square copper plated steel
box painted black, 3 1/4" deep, the mirrored meter is
5" wide and 2 3/8" high, the coil is HUGE by most
meter standards 1 1/8" X 1 3/8", the moving coil is
inside an aluminum doughnut.  There are no protecting
diodes of any kind, just two coils, evidently series
resistors.  BTW, there are three tiny balancing nuts
on the needle placed at 90 degrees apart from the
needle itself.  Mostly it's a bare meter movement.  I
have a similar DC current meter to pair with it if I
can keep it working.  The needle is free, responds to
full scale with the puff test, smoothly, too.

It's not, however, my biggest meter, that's a Welch
that's 14" X 14", YES, the ones you saw in high school
science class!

The Steel-Six came from the USAF and is due to be
calibrated again in 2006!  That's why this is such a
bugger.  Anyway, the meter glass had been replaced
before I got it because it was plexiglas, I just put
in a new piece of REAL glass, no telling what went in
there over its life time, but it is dusty in there.

Thanks, good suggestions,

Joe

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