{Collins} Re: Best contact cleaner ?


I have used DeoxIT D5 for years with excellent results.  Even some Radio Sh=
acks have had it, or you could try Antique Electronics Supply.  The trick i=
s not to overspray - just enough to wet the affected contacts and wafer met=
al sections.  However - trying to get a Q tip or anything else close enough=
 to do that in tight areas has its own risks if you hit something on the wa=
y in or out.  Turn the spray to minimum and be very sparing.  This really e=
liminates a lot of problems.  In addition to the obvious switch contacts, d=
o not neglect the relays (ALL of them), the RCA connectors, and the mike an=
d phone connectors.    I also spray the tube pins before I reinsert the tub=
es after inspection and pin straightening.  For units with plug in crystals=
, I also spray the pins and work the crystals in and out, especially if the=
 crystal can shows any hint of corrosion (quite common and may indicate cor=
roded crystal pins).  In short, all metal faying surfaces shoulld be clear =
of corrosion and dirt to provide low resistance pressure contacts as design=
ed.  After getting the contact cleaner on the surfaces, rotate, plug/unplug=
, etc several times to work the surfaces against each other - this mechanic=
al wiping is part of the parts' designs and will help clear the gunk left f=
rom past decades.

Note that some relay contacts, if badly burned and pitted, might need more =
agressive polishing with a burnishing tool.  However, I use a sliver cut fr=
om a business card and wetted with DeoxIT to insert between the open and cl=
osed contacts.  If you can, use your finger to move the contacts towards ea=
ch other, one by one, with the wetted card in between and work the sliver b=
ack and forth gently.  This old trick really gets the crud out - you will s=
ee the black lines on the card.  If the relay is still intermittent, burnis=
hing may be the only way out, short of replacing the relay, but the card wi=
ll clear 99% of the problems.  If your radio has intermittent low gain on r=
eceive (common), you likely have crudded up relay contacts.  Note that some=
 relays are plug in's and some are permanently mounted, so getting to the c=
ontacts can be interesting; that's where the bent sliver of business card i=
s handy - bend it to get the card where it needs to go, and be very, very c=
areful not to hit anything else on the way in/out.     =20

Doing all of this really helps to eliminate a lot of headaches before you a=
ttempt an alignment, for example.  It's surprising how lively a radio will =
become after cleaning out the contacts - unless you have other problems, su=
ch as bad tubes, etc.  Also - after you have used the cleaner and have the =
radio operating, exercising the various functions one by one (such as tryin=
g all band positions) while listening or transmitting can reveal many inter=
mittents.  A flaky bandswitch might show up on one or two bands, which can =
help pinpoint something to be fixed while the unit is on the bench.

Hope this helps.  There are many opinions on this subject (freon, etc).  Bu=
t DeoxIT is a perenial favorite for boatanchor enthusiasts for good reasons=
.  BTW - NEVER spray anything like cleaners on plastic if you can avoid it.=
  And don't soak fiber wafers on the switches (although they will eventuall=
y dry out).

This sort of cleaning is relatively easy to do, whether you are an expert o=
r a novice.  Just make sure everything is back in the right place when you =
are finished, especially the tubes! =20


Rocco N6KN

-----Original Message----- . . .
>From: Dan Eisenman <sales@xxxxxxxxxxxxxxx>

>I'm about to get new to me a KWM-2 , what is the best cleaner for=20
>controls and switches ?
>73 Dan
>K8ICB in Florida

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