From: Eric Webner 
Subject: Re: [drakelist] R4C xtal bank bad

are a result of wafer misalignment or wafer center hole wear.
Making sure the switch assembly hardware is tight and properly
aligned and keeping shaft bearing surfaces lubricated will
correct the first and help mitigate the last.Silver
"cleaners" clean by removing, either by chemical or mechanical
means, silver (di?)sulfide. This is the black stuff seen on
silver items. Unfortunately, when you remove silver disulfide,
you are by definition removing "some" silver. The thing
is, silver disulfide is very soft, and easily displaced by the
spring action of the switch contacts. You can see this by looking
closely at the blackened area of a switch.!
 You will
 see a bright silver line where the contact has been wiping. By
the way, the black deposit is essentially as conductive as
silver.The bad news is that any chemical or
mechanical abrasive that is left behind on the switch after
"cleaning" continues to work.DeoxiT is
excellent at removing minute amounts of corrosion at the contact
points without attacking the _thin_ silver layer, restoring
electrical conductivity. Liquid DeoxiT (Was D100L under old
nomenclature) is best, since you want it only on the contact
area, NOT all over everything in the general area to attract and
hold dust.The only reason I see for
"cleaning" switch silver is for appearance, which is
perhaps important if you are competing in a concours show! The
inherent hazards, not to mention the danger of "springing" or
otherwise damaging small contact elements by poking around them
with tools, far outweigh any positive
effects.73, Garey -
 K4OAHAtlantaDrake C-Line Service
Manual<HTTP: R-4C_Servicez hr99.home.mindspring.com
/>Eric Webner
wrote:> Hi Joe,>
> Have you made any progress on your radio? I didn't see
any responses > on drakelist.>
> It seems the crystals are ok, so it must be a wire or
more probably, a > switch contact. The wafer switches on
these radios seem to corrode a > bit, with the metal parts
turning black. You might be able to clean > the rotary
switch contacts sufficiently with De-Oxit, but I used a >
more thorough method on all the switches in my T-4XC. Check out
>
http://www.wb4hfn.com/DrakeArticles/CleaningSwitches/CleaningSwitches.htm
for > details.> > BTW,
this web site is very well done and you will want to explore the
> other articles on it. Good luck.>
> 73,> > Eric
KA8FAN>> */Joe Roth
/*
 wrote:>>> "Joe
Roth" made an utterence to the drakelist gang>
---------------------------------------------------------------------->
I've added a lot of xtals to my R4C. I began to use position
11> which is now> in the 3 (bottom most)
row. The entire row for positions 11-15> will
not> work. The receiver acts as if the xtal sockets are
empty. The xtal> works> fine in other
positions. I've swapped all combinations around and> I
know> there is a problem with the row. I looked at the
obvious solder> joints on> the switch and
traced the connections of 3 wires going to the> underside
of> the chassis. Everything appears to be
okay.> I now need to get in to it deeper and trace some
lines with the> VOM. Does> anyone have
suggestions to narrow things down?> TNX>
Joe/N4ARI>
www.n4ari.net>>>
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