----- Original Message -----
From: "Jim Bo" <[email protected]>
To: <[email protected]>
Sent: Sunday, January 30, 2011 9:13 AM
Subject: [Drakelist] Solved T-4XC Loss of Pwr and Side Tone
issue
Thanks to ALL and everyone for help with this month old
problem. The 160 meter CW contest drove me over the edge
with my TS-480 on receive, and had to sort out the C line
xmitter issue so I could easily use the R-4C, or be in the
depths of AGC pumping for the weekend.
Took a hair dryer and heated the under chassis area of V9
(Osc) and V7 (Amp) on T-4XC and initially the problem did
not arise.
I continued to heat to the point I was concerned it was
getting to hot, and the output power went to zero and
sidetone was gone.
I sprayed "freeze it" on the componenets in the area of V9
and V7 and no change.
I then wiggled V9 and noticed the power was intermittent. I
replaced tube and had the same issue. I resoldered all
solder joints on V9 and still had the same issue.
I took a "pick" and "adjusted" the pins of the tube socket
and the problem was solved.
Occam's Razor baby........................just Occam's
Razor!
Jim
WA9ZBV
I think this is important: we tend to take things like
tube sockets for granted because they seldom cause problems.
But... they do wear and corrode, if subject to a lot of
heat, as the sockets of final tubes are, the contacts can
lose their springiness. I also had a problem where a tube
did not work in the transmitter but did when put on either a
socket extender or tube tester. _That_ turned out to be the
tube pins and working them over with a wire brush cured the
problem.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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