----- Original Message -----
From: "m coffey" <[email protected]>
To: <[email protected]>
Sent: Monday, March 05, 2012 4:16 PM
Subject: [Drakelist] Trouble with TR4 ?
First, I would like to thanks those who p osted info
on whitening
pointer knobs and the TR4 tube shields.
Now, after having cleaned the switches and
cleaned/reseated all the
tubes, etc., I am trying out receive side on the radio
with a 75ft. random
wire. 20 and 80 have signals, but thats about it. Fairly
low volume and no
movement on the S meter ( S meter zero works fine). Also
when switching
between 20, 40, 80M, the sideband switches everytime and I
have to correct
it with the sideband switch ( normal?). When the
calibratetor is used, I
have it fine on 80 and 20 (with a constant low tone in
background) but not
on 40. Also no indication of calibrate on S meter. I got
spare tubes with
the radio (boxed but unchecked) and went through and
subbed all the tubes
in the receive line one by one, no change.
Thoughts, suggestions? Mike.
I found the some positions of the bandswitch on my TR-4
were persistently intermittant. I would clean them with
Deoxit and work them and all would be fine. Then, the next
day all 10 meter bands were dead. I finally cleanded the
switch and coated it lightly with Tuner-Lub. That resulted
in a pretty much permanent fix. I am not sure what happens
to these switches but suspect the pressure of the contacts
against the sliding part becomes weak. Rotary switches are
_supposed_ to be self cleaning because of the sliding
action. I suppose it works better if switches are
constantly in use. I had a similar thing in an SP-600-JX
where the IF bandwidth switch became intermittant. Cleaned
several times with Deoxit but it became noisy and
intermittant again in a few days. Here again Tuner-Lub seems
to have given a long term fix. Of course, there may be
other problems with the TR-4 but I suggest that even if you
have gone through and worked the screws and cleaned the
switches to do it again. Its simple and might fix the
problem.
Its also possible that the thing is way out of
alignment. If the above voodoo doesn't fix it I suggest
going through the alignment procedure.
Its normal for the side band indicator to switch with
the band. Its set up for the most commonly used sideband on
each band.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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