[R-390] R-390A Buying Tips

[James Miller]

And don't forget the diodes to replace the flaky rectifier tubes'
Or the surge limiter;
Or the 10 turn pot to replace that poorly designed single turn meter adjust
circuit;
Or the PTO that has been torn down, rebuilt and linearized to within 50 Hz
everywhere;
Or the DISC ceramic caos that have been replaced anywhere they touch the AGC
line and screens (yes, their dielectrics leak too)... added about 20 dB to
signal levels.
How far shall I go?
Both of my 390As arrived as basket cases, practically dead.
Now they will probably outperform 95% of the untouched museum pieces around.
And I have a couple of degrees in EE and Advanced Calculus, for what that's
worth.  But I didn't let that get in the way of truth and reality.  Now
let's put our Jacobians, LaPlace transforms and matrix inversions aside and
enjoy our valves.


----- Original Message ----- 
From: "Dallas Lankford" <dallas at bayou.com>
To: <r-390 at mailman.qth.net>
Sent: Friday, January 14, 2005 10:07 PM
Subject: [R-390] R-390A Buying Tips


There are so many of those parking lot of doom R-390A's floating around
(puns intended) that one should be extremely cautious about buying any
R-390A's.  For a long time I couldn't think of a foolproof way to identify
them, so as not to get burned (or should I say rained on?).  But duuhuhh.
The answer is as plain as the nose on my face.  Look at the capacitors dummy
says me to myself!  If it has a bunch of bright orange capacitors in the IF
deck, there is a high likelihood that it sat in a parking lot for several
years.  You might miss a few good R-390A's by culling the ones with the
bright orange capacitors, but such is life.  Or if it has a bunch of brown
beauties with big cracks, especially with cracks painted white, then you
know you have a loser.  Be sure to bring an 8X loupe and look for
microscopic cracks along the mould lines.  Those are also losers.  The
capacitor replacers have done us fastidious R-390A buyers a wonderful
service by helping to identify the ones we do not want.  Also look for grit
in all the nooks and crannies.  It is really difficult to get all the grit
out of a parking lot R-390A.  And look closely at all the screws.  If you
see any rust, don't buy.  The screws are stainless and can tolerate damp
environments, but if you leave stainless out in the rain for a while, it
will start to rust.  I must admit that I did not think of all of these tips
myself.  And I would like to give credit where credit is due.  But to keep
the rotten tomatoes directed at me only, I have kept my sources anonymous.
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Internal Virus Database is out-of-date.
Checked by AVG Anti-Virus.
Version: 7.0.300 / Virus Database: 265.6.8 - Release Date: 1/3/2005