Andrew Mitz wrote:

"Larry Gagnon" wrote in message
newsan.2004.12.15.21.21.27.858623@fakeuniserve .com...


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


I have repaired a number of Epoxy Potted VCO modules by simply resoldering ALL of the PCB board connections !
The source of the problem is difference in the Coefficient of Expansion
between the Epoxy potting compound and the PCB and the solder
connections. Close inspection (under a microscope) will show that the
joints in question have been fractured by repeated thermal cycling. Hand
resoldering, rather than the original Wave-Soldering will produce a
much stronger bond between the component leads and the PC board and
reduce the problem.

Yukio YANO VE5YS