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Old 26th Aug 2019, 3:55 pm   #24
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Join Date: Nov 2010
Location: North Hykeham, Lincolnshire, UK.
Posts: 515
Default Re: Substance applied to Radio circuit board screws ?

Originally Posted by Richard_FM View Post
A lot of older portable radio PCBs from the Far East had a layer of wax dripped over them to stop the components to stop them moving due to being loosely soldered.
That's not quite right.

I think you'll find that the wax was mainly used in FM radios with airspaced inductors. The alignment involved stretching and compressing the inductors as necessary and then applying the wax to stop them moving. It also stopped microphony which would be a bit of a problem if it affected the oscillator coil!

The wax may have covered other nearby components as well, as the wax puddle spread out before setting.
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