[Hallicrafters] Relay Cleaning Question to all

[Barry Hauser]

Hi Greg

I've been reading the replies to your relay situation.  Agree with most
of them as first steps.  However, it's possible that the contacts are a
bit too far gone to respond to burnishing, etc.  Usually, relay contacts
- just the tiny button parts -- are plated with silver or gold.  From
repeated use, the plating can wear through.  Sometimes you'll get away
with cleaning what's left, however often they continue to oxidize quickly
and may stick or become intermittent.  

One possible permanent fix is to replate the contact points.  I don't
know what that relay looks like, but many older open style relays can be
disassembled at least partially, or the coil is on a long bolt and can be
removed.  Or somehow the contact ends can be suspended in a small
electroplating tank with the current connected to all of the contact
terminals at once.  If going to that trouble, you might as well go for
the gold, which is most likely to be reliable.  How to get it done?  I
think you can buy small electroplating kits.  The gold stuff for brush
electroplating is very expensive.  But maybe the best bet would be a
jeweler -- one that does restorations of things like watch cases, etc.

Another possible problem there is the bond between the little contact
rivets and the relay leaves or arms.  Usually these are staked in.  They
could be slightly loose or corrosion has developed between the rivets and
the leaves/arms.

Another thought -- Caig, manufacturer of DeOxit, also makes a product
called ProGold.  It's mainly intended for gold plated switch contacts and
edge connector surfaces.  Not sure if it will work on relay contacts
which are continuously being "hammered".  It's supposed to deposit or
replenish a thin layer of gold.  It's about 50% more costly than DeOxit. 


Haven't tried either of these myself -- so you go first and tell us how
you make out. ;-)

Barry


On Thu, 31 Jan 2002 21:29:13 -0700 greg mijal <bmw at sonalink.com> writes:
> Hello glowbugs!!!
> 
> I got a good question for you.
> 
> It's not about Hallicrafters stuff but it's close.
 
> I got a NCX 5 very close to completion of repairs but do a have a 
> bug.  That stinky little tr relay, which I have tuned to mechanical 
> perfection and de-oxed the whiz out of, still acts like it has some
crud on 
> it. That is, sometimes it causes squiggly audio out of the receiver and

> loss  of RIT control.
> I've tried scrubbing bubbles, tlc, deoxit and TNT but nothing seems 
> to > really peneatrate the crud on the little ball-heads of the 
> contacts.  Can someone recommend a procedure or products that can 
> non-destructively clear it out? Perhaps something like a long term
soak?  I have the 
> last known semi operational NCX 5 tr relay in the known universe and 
> would just love to get the Malden, Mass Monster back on the air.
> 73's Greg WA7LYO
> in sunny Feenix (snowed yesterday)
> 
> 
> 
> 
> _______________________________________________
> List Administrator: Duane Fischer, W8DBF **for assistance**
> dfischer at usol.com
> ----
> Hallicrafters Collectors International: http://www.w9wze.org
> ----
> http://mailman.qth.net/mailman/listinfo/hallicrafters
> 
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno.com/get/web/.