A CRITICAL thing to do/check.
Get in there close with lots of light and a magnafier if necessary.
Look at each switch contact on each wafer and look for significant
movement or wipe we call it...when the rotor gets there.
AND be sure the alignment is good as to position on the wafers of the
rotors...adj if needed.
Also, a very slight re-adj of the rotor position will help with any
contacts that don't seem to work unless wiggled a little sometimes.
These are designed to be self cleaning and will IF there is slight wipe
on each contact.
Also, if you can get it to fail on a specific band while in
there.....just gently touch (insulated tool, of course) each contact
that should be making..if you find one that works when touched...you
can clean it a little...maybe use a pecil eraser (NOT one that is very
abasive like on a ink eraser)...or other means.
NEVER use anything abrasive, like 400 paper & such. The silver coating
needs to stay on it.
FWIW.
73,
Lee
-----Original Message-----
From: Dick KF4NS <kf4nsra...@verizon.net>
To: kb8bku <kb8...@woh.rr.com>
Cc: drakelist <drakelist@zerobeat.net>
Sent: Sat, Dec 24, 2011 4:38 pm
Subject: Re: [Drakelist] problem with deoxit
Darryl,
I cannot say with any real certainty but I ran into a similar
situation. I used
just a tiny amount as I
have for years but the Drake TR4C did not react kindly. Now a bit on
your main
problem; I also have
trouble on 40M but I am certain it is the contacts for 40M on the band
switches.
I cleaned all the
contacts with alcohol and it worked ok for a while but then back to
same ole
same ole. I am convinced
that this is not uncommon for the Drakes. Those bandswitch contacts
seem to be a
recurring problem but
the cure is worse than the status quo. Forget about removing the switch
wafers
for ANY reason. I, like
most true hams, never give up and never will. One way or another I will
fix it
before I go to the great
shack in the sky.
Merry Christmas and Happy New Year.
73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow!
----- Original Message ----- |
| Message: 3
| Date: Sat, 24 Dec 2011 10:44:53 -0500
| From: kb8bku <kb8...@woh.rr.com>
| To: y...@aol.com, drakelist@zerobeat.net
| Subject: [Drakelist] problem with deoxit
| Message-ID: <115f4d38-3e02-4a55-ad4f-75d9835c3...@woh.rr.com>
| Content-Type: text/plain; charset=us-ascii
|
| Dale,
|
| I had a somewhat similar experience. I hadn't written, as I was
reluctant to
badmouth the De-oxit, as
that seems to be the cleaner/lubricant of choice with the Drake crowd.
I just
figured it must be
something else, and it probably is. I got some of the tiny pink $3
tubes
(D-100L) at hamvention to see
what all the crowing was about. My R-4A would cut-out on 40
intermitantly, but
rocking the bandswitch
would restore operation. It had been ~5 years since I had cleaned and
lubed it
with Blue Shower cleaner
and lubed with Blue Stuff for tuners. I very carefully cleaned the
bandswitch
with Q-tips and alcohol,
then lubed very sparing with De-Oxit on a Q-tip. I was very careful to
avoid
leaving cotton fibers in
the switch mechanism. When I powered up the next day I had lost
sensitivity
according to the S-meter
(signals from antenna as well as calibrator were reduced from S9 or ten
over 9
to S5-S7). I checked for
lose tubes, etc., but found no cause. I rechecked the sensitivity
| adjustment, but no soap.
|
| I had begun experiencing audio hum, so while I had the radio opened,
I
re-caped the three sections of
the electrolytic can at the same time as I cleaned the bandswitch. The
hum do
go away, and I looked for
any big DC changes (due to the re-cap) that might throw things off, but
didn't
see that.
|
| I have been unable to conclude that I have AGC problems, which is
what I might
first expect. One good
thing, my 40mtr xtal osc. circuit works better than ever. It has
always been
iffy, and I usually used
the FS-4 when I was on 40 for that reason.
|
| I will let you know if I figure anything out. Suggestions welcome,
although I
realize this isn't much
to go on. My first second, and third assumptions were that I disturbed
something to cause my problem.
This is my first experience with De-Oxit. I am quite experienced with
these
types of radio repair. I've
tried to imagine what I disturbed and check that, but to no avail so
far.
|
| Working at a relaxed pace,
|
| KB8BKU, Darryl in Dayton
|
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