[R-390] Line filter issues possibly solved!

Tue, 12 Aug 2003 19:27:50 -0400

All: I know I will be hung in Effigy (that's a small town in IL) for
suggesting this, but I replaced the line filter with a modern, up-to-date
CORCOM line filter / IEC connector combo.  I can now use any one of a dozen
instrument cords to connect the radio, and I get a good 3-wire connection
(assuming of course the cord's good to start with).

For what it's worth.
Dave WB4FUR

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of [email protected]
Sent: Friday, August 08, 2003 4:54 PM
To: [email protected]; [email protected]
Subject: [R-390] Line filter issues possibly solved!

Yet another update: I think I may finally have found the solution to this
enigma! I decided to check the line cord connections in the back of the 390A
to
see if the noise went away when taking off the power cord wires. While
loosening the nut holding the neutral on, I noticed that the connecting lug
was moving
an awful lot along with my loosening attempts. After finally managing to get
the bolt fully loosened, which badly bent the connecting lug, the noise did
not go away, so I loosened the nut holding the hot lead, removed ground lead
from the rear panel, then removed the hot lead from it's terminal on the
line
filter, upon which the noise stopped radiating. Discouraged, I then
attempted to
remount the neutral lead to it's terminal on the line filter, upon which the
connecting lead began moving surprisingly well in the opposite direction,
shearing the neutral connecting lug off. I then noticed a crack which went
all
around the ceramic insulator on the line filter. Stress must've cracked the
insulator at the point where the terminal screw ends, and this allows the
terminal
screw to rotate freely. I suspect that there was enough of a connection to
allow the radio to work, but it also formed one hell of a diode-like
semiconducting connection, which sent even the tiniest amount of line noise
radiating from
the line filter out the neutral lead like an antenna. What would be the best
method to remove the line filter, especially that cramped screw? Also, might
anyone have a spare line filter lying around that they could spare?
-Adam

Adam Vaughn
Collector of old computers, video game systems, radios and other electronic
equipment...
Visit my page at
http://www.angelfire.com/ma2/AdamVon/index.html

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