[R-390] RE: Using Surplus Meters

[Laird Tom N]

The following is from my archives dated 1997. I'm not sure if any meter
sets are still available or even the status of the author! You still may
have to do the op-amp trick.

Tom Laird WC9M
Moline, IL.
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I have located a source for some used meters
that are very similar in appearance to the original meters used in the
R-390a's. I took the meter faces from my original R-390a meters and
scanned them into a drawing program so that I am able to print them out
on adhesive backed polyester sheets. I then dissasembled the new (used)
meters and applied the labels to the back of the meter cards,
reassembled, and voila, instant R-390A meters!

Of course there is the matter of converting the line level meter over
to AC operation, but this is easily done with a bridge rectifier. The
rating of the new meters are 30 ohms at 1 mA for the carrier level
meter and 100 ohms at 1 mA for the line level. I was skeptcal at first
that I would have much luck with the line level meters due to the great
difference between the specs of the originals and the replacements. I
have found, however, that functionally the only difference is that when
the Line Meter attenuation switch is set one position higher the
behavior of the meter is almost identical to the original.

A couple of my friends saw my R-725 with its new meters and wondered
where in the heck I had managed to come up with a set of original meters
for the thing. After I told them the secret I gave them the parts and a
few instructions and now they too have working meters where there used
to be holes. They liked the new meters so much that they talked me into
getting busy and making up a set of illustrated instructions on my computer.

My question for you BA folks is this; How many of you might be
interested in a R-390a meter kit, with all of the parts and instructions
for the prncely sum of $25, shipped? This is about what I figure it
would take in order to pay for the parts and make it worthwhile to run
back and forth to the post office. The kit would include all mounting
hardware, 2 used (checked) meters, meter appliques in both white on
black and black on white, diodes, and an instruction sheet.

Tom KK8M
THOMAS W BOWES
5529 25 MILE RD
SHELBY TOWNSHIP MI 48316