[R-390] Crystal resurrection

[Mark Richards]

As I work through some issues with my R-390A crystal oscillator, two 
crystals were identified as non-functioning: Y402, 10.5MHz and Y413, 
9.5MHz.  Considering the cost of replacing these at the only supplier I 
could find, Fair Radio, I figured that a repair try which saves me $14 
each is worth the gamble.

After some digging, I found a fellow traveler:

     http://home.earthlink.net/~chestnutl/Helptipspage3.html

The author found in one instance the internal crystal structure was 
touching the cover which prevented oscillation and, in another crystal, 
that re-soldering was needed.

Rather than use a torch, I set my soldering iron to around 800 degrees F 
and after a minute or so managed to carefully wiggle up the cover.

In both crystals there was no obvious alignment problem, so I set about 
to renew the soldering.  But, before that, I cleaned each crystal using 
isopropyl alcohol applied carefully with a cotton ball.  Then, with the 
soldering iron, touched up each lead, first at the very base where it 
attaches to the pin, and then carefully moved up to the crystal element, 
adding a bit of solder.  This was done at around 650 Degrees F.

Tacking the cover back to allow for re-insertion we have success: each 
crystal came to life!

Perhaps this is non-preservation-quality, but 30 minutes of careful 
effort just saved me $28 I didn't have to throw.

This R-390A radio is one tough unit!

/K1MGY