[TenTec] OT: Acoustic Silencing Switching PS Transformers

[Kim Elmore]

This is admittedly off-topic, but if any expertise exists I figure it 
will be among the denizens of this list.

I have a Kenwood TS-930S with the Piexx enhanced microprocessor board 
installed. That board uses a small, on-board switching power supply. The 
board works flawlessly, as does the rig. The problem is that the 
transformer, which uses a two-piece ferrite core, "sings" at a frequency 
that I can't hear, but that my kids can and find annoying. Chris at 
Piexx said to squeeze the transformer a bit and, in messing with it, 
I'll probably silence it. Indeed, I managed to do so and in the process 
found several situations where even I could hear it and it was 
surprisingly loud , but the problem has returned. Chris is sending me a 
metal clip that is now used on the transformer in hopes that it will 
permanently solve the problem.

If the clip doesn't do the trick, can I get away with getting the 
transformer silent and then applying Q-Dope or some thinned epoxy to 
hold it in whatever position keeps it quiet (sort of a half-baked 
potting process)? Or will that, instead, guarantee that I'll never be 
able to fix it if the ferrite halves shift a tiny bit as everything sets up?

Kim N5OP



-- 

Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP 
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)

/"In theory there is no difference between theory and practice. But, in 
practice, there is." //-- Attributed to many people; it's so true that 
it doesn't matter who said it./