[R-390] Meter Meister?

[Barry Hauser]

Joe wrote:
> BTW, there are three tiny balancing nuts
> on the needle placed at 90 degrees apart from the
> needle itself.

Sounds more complicated than usual.

  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.

Probably not particles or misalignment of the armature then.  Sometimes I've
come across such severe static that a meter won't zero -- just hangs
wherever you point to on the "glass".  (Mostly happens with plastic lenses.)
I doubt if that's it given the vintage and so on and that usually clears up
sitting around or when subject to some current.

Have you tried running the meter out of it's case?  Does it have a range
switch with precision resistors. Maybe one is bad.  You said it won't go
above 2 volts, but will peg with reversed polarity -- how much swing between
zero and "peg left"?  Might be 2 volts or less.  Does it have other ranges?

Barry