fm tuner, wax on components ?

[phil]

My fm tuner circuit is very strange, it has wax all over some parts of
it and inside a coil there is also a spunge which it seems was soaked
in wax.

Any ideas what all this wax is for ?

 

[Michael Black]

"phil" (aaa@aaaaaaaa.com) writes:

My fm tuner circuit is very strange, it has wax all over some parts of
it and inside a coil there is also a spunge which it seems was soaked
in wax.

Any ideas what all this wax is for ?


To provide a level of mechanical stability.

If the windings move around, the coils will vary in inductance, and
so you'll get a mistuned receiver in some fashion.

Wax is something to apply, and if you really need to do work on
that coil, it's relatively easy to melt off.

Michael

 

[Matt J. McCullar]

It keeps all of those components mechanically stable. When you're working
with frequencies that high, any slight movement of the radio will make the
receiver frequency wander all over the place and you'll definitely hear it.

I built some ham radio CW transmitters that were not mechanically stable and
you could definitely hear a pitch change whenever you tapped the circuit
board.