On Feb 22, 8:40*am, Ned Simmons wrote:
On Sun, 21 Feb 2010 19:58:39 -0500, "Wild_Bill"

wrote:

I'd just naturally suspect the blue tantalum capacitors, just because of
their age.

Easy and cheap to replace.

Not necessarily cheap, there are wet slug tantalum capacitors for
military/aerospace
use in the range of $30 each. Unless there's a damaged case,
tantalums
fail in short circuit, i.e. if there's voltage across the pins, it's
good.

If it counts UP always, the possibility is that there are two channels
with crosstalk,
in a quadrature counter. Quadrature works by having (for example) a
pair of gear
tooth sensors offset, so if the gear hits sensor 1 first, then sensor
2, you know it's
moving CCW; if it hits sensor 2 first, then sensor 1, it's CW. If
both sensors report
at the same time, direction gets confused but you KNOW it moved. If
there's
a way to clean or reregister the sensors and the scale, I'd start
there. Then
look for wiring common to both sensors (the power supply components in
the sense
head, for instance).