[Milsurplus] IT'S FIXED! Or, How NOT ro clean a crystal.

[Philip Atchley]

Hi all,
I just got the Xtal filter in my BC-342N fixed and working as it should.  I
was certain it was the Xtal, and I was right.

1.  The other day I carefully dis-assembled the Xtal and cleaned it very
thoroughly, removing oil and other gunk that had infiltrated the package,
using some of my very precious Freon TF (no longer available to the
technical service folks who repair stereos (like yours truly).  This is a
very good solvent that leaves absolutely no residue and dries nearly
instantly.  99% alcohol from the drugstore would probably also work.

The I very carefully covered the entire Xtal with clear polyurethane varnish
just like it was originally varnished, to seal all the seams etc (there are
no rubber seals, this is two heavy steel plates sandwiching a hollow ceramic
spacer with the Xtal in the hollow spot).  BIG MISTAKE!

2.  Today I decided I couldn't hurt it any, I pulled the Xtal out of the
receiver again.  Fully disassembled it only to find that there was undried
Polyurethane "goo" everywhere inside the package, including on the Xtal
itself.  Those seams are really leaky!  So, first I scraped the thick
polyurethane off the outside parts and then I soaked all the parts
(including the Xtal element) for an hour or so in gasoline (outside in the
fresh air) to make sure it was all off.  They cleaned up nicely.  After than
I poured some of the Freon TF in a small container, let the Xtal soak in it
for 10-15 minutes to make sure it was really clean, shaking it gently every
once in awhile.  After I dried it off I used the remaining TF that was in
that container with Q tips to really clean the metal cover plates (one plate
has small feedthrough insulators for the screws to pass through, don't lose
them).

After reassembling it I temporarily installed it in the receiver.  Eureka!
It worked!  I again removed it to seal it up, but NOT with Polyurethane.  I
used black tape, carefully sealing all seams, screw heads etc then giving it
a number of good tight wraps to make sure it stays sealed.

3.  Upon reinstalling it It checked out perfectly.   I'll let it sit there
and cook awhile, then align the complete IF strip to the Crystal frequency
(now that I have one <grin>.

73 from the "Beaconeers Lair".
Phil, KO6BB

DX begins at the noise floor!
Merced, Central California
37.18N  120.29W  CM97sh