[Hallicrafters] SX-101 wafer switch Question

[Mark Shaum]

>I'm starting to go on circles. My main question is, is there anything
that can cause this problem beside the Response rotary switch?  If, not,
is there an >easy way to clean the switch beside soaking the complete
wafer with Deoxit?

I have a HQ-170 that developed the oft-reported very intermittant
Hammarlund bandswitch syndrome.  I suspected some gunk had a accumulated
over time in storage, and observing the ceramic HF osc switch wafers
confirmed that. My storage area is heated and humidity controlled, but
it's also where I park my vehicles and yard toys, so some "stuff" does
wander in and find the boatanchors over time.  I really ought to sew up
some nice fitting cotton covers for the sets that are not in use. Back
to the switch. De-Oxit alone helped a bit but did not restore it to its
former stability.  What I eventually tried, was using one of those
solder-sucker bulbs to force-spray 91% alcohol into, around and over the
ceramic wafers a few times.  The wafers certainly cleaned up nice and
bright with no visible residue.  I followed this up with using the
eye-dropper style concentrated De-Oxit, careful only to apply it to the
rotor blades and stationary contacts.  The result is a HQ-170 that can
again receive stable SSB on 10 meters and even put up with a bit of
bandswitch jiggling without jumping all over the place.  Six meters is
another story, I don't think any of the Hammarlunds that included
built-in 6 meters (without a converter) like the 110's and 170's are
going to be solid at 50 Mhz.  Good enough for CW but not SSB.

Your problem may not be the switch.  It may be necessary to replace the
tuned circuit components utilized by the oscillator that won't, but as
you have spare parts now, at least you won't have to wait to acquire
them.

The only wafer switch I currently despise that refuses to stay solid is
the meter switch on my Ranger II.  I don't see much choice but to
replace it with a decent 2-pole ceramic switch, and that will be done
the next time the front panel comes off.  It has NOT responded to the
above treatment, the intermittant contact returns from a few days to a
couple weeks later.

73! - Mark K9TR
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Mark Shaum K9TR
email: k9tr at dtnspeed.net
http://www.qsl.net/k9tr
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