"Avery Fineman" wrote in message
...
In article , "Chuckie"
writes:

"Larry Gagnon" wrote in message
newsan.2004.12.15.21.21.27.858623@fakeuniserve. com...
I posted a few days ago about repairing a VHF marine radio. Thankfully
I
solved my problem, locating three cold solder joints in the VCO, which
entailed removing metal shields and all the beeswax that coated all the
components. That was character building work!

I gather the beeswax is to ensure rigid components to maintain
stability
of the oscillator? Any other reasons for it? Is it necessary for me to
remelt the old wax and spread it around as before, or can I get away
with
just reshielding the VCO?

Any suggestions appreciated.

Larry VE7EA

--
Beeswax goes back the the 1930s USA designed radios too.
In common radio design use since then.
It is excellent as it has a high melting point (for waxes).
Just put some it back on, it keeps the coils/wires stationary.
You should only need a line on both sides of the coil.

Quite true on old-time radio production, but primarily for the
lower-cost "consumer" type models.

The wax isn't from bees, but rather from other sources and is
usually called "ceresin wax." Pours easily when hot, stays hot
enough for a quick brushing-on. Unfortunately, hot spots in old
tube/valve equipment lets the wax soften and it sometimes dribbles
off and quits holding what it was supposed to hold.

O-T story: Back in 1956 when I was new to WREX-TV and on
midnight maintenance shift, I was supposed to align the air
monitor scope that sampled the transmitter output signal. The
video response was way off judging by the sync signal appearance.
Cause was the peaking coils of the internal tube video amplifier. An
hour spent with a video sweep generator and a hot iron brought the
peaking coils (pie-wound inductors sliding on 1 Watt resistor bodies)
into a good, flat video response. Early day shift complained long and
loud about "the air monitor doesn't work!" It showed the correct
waveform, not the one they were used to! :-) [nobody had been able
to fix it before and all it took was to move the coils slightly to
adjust
their inductance]

There's nothing special about the wax. It was a convenience to use
in production, quick, easy-to-use and cheap. To do a good hold on
things like inductors, I would recommend the "spar varnish" kind of
varnish (made from pretroleum distilates, not the urethane type). One
example of that is McCloskey "Gym Seal" intended for hard-use
floor finishing and found in lumber yards and do-it-yourself stores.
Varnish needs to cure overnight to be effective, doesn't drop Q any
more than the polystyrene "Q Dope" (which will lose its holding power
because of moisture breaking the bond to the work), and holds on
infinitum (also known as at least 30 years based on my experience).



Remember "fish-paper"? used that in a early 1980 moto radio design.
I know the type of wax you are talking about, harder and a little darker
than beeswax.