[Milsurplus] FT-241 surplus LF crystals chan - freq list ?

[Hubert Miller]

Very interesting. My information about the failure modes was based on reports from members of the Glowbugs list. Some years back, in what is now
recalled as "The Great Crystal Caper", a stash of forgotten surplus LF crystals was found. The stash was apportioned into lots and sold off to all comers.
The sad reports of high failure rates followed. Some people opened them up to do a post mortems.
I have never heard of the moss phenomenon. I did read somewhere about cleaning the crystal. I don't mean scrubbing the wax off, as with the 915 kHz
rock in the BC-348, or using an etchant solution. I'll try to note that advice when I find it again. Maybe in some article on crystal grinding.
The LF crystals where the plated on lead has popped off, I wonder if it would work, to remove the other side's contact too, then grind the surfaces slightly
to restore the smooth plane, and then repackage in another holder?

Robert, what kind of test oscillator circuit did you use for checking these?
-Hue

Subject: Re: [Milsurplus] FT-241 surplus LF crystals chan - freq list ?

>From examining two or three about 10 or 15 years ago, I concluded that the failure (or actually the failure to remain resonant at the original frequency because I found several that oscillated reliably in the range of about 3X the original frequency) was caused by a buildup of something green on both sides of the blank.  A magic potion that could dissolve the green without effecting the original constituents would be a possible solution.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480



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