[Kenwood] TV-506 22 MHz Oscillator Problems

[John Ely]

Jerry, thanks for the information.

I removed the trimmer today and applied some Cramolin before
soldering it back in.  There was no change.

I also removed the 3 pF capacitor in parallel with the trimmer
and it seemed to get worse.  I then added 8 pF DSM where
the 3 pF was.  It works a little better, but the frequency is
a few hundred Hz lower than 22. 000 0 MHz.

>That's a lot of shift for a good crystal. Just a little too much for
>external influences, like the trimmer capacitor going open (which you
>could check with a quarter drop of DeoXit where the trimmer shaft hits
>the clip, if its not mounted flush to the PC board to make that point
>inaccessible).

The frequency at the trimmer/crystal is indeed changing.

>You could check for fundamental operation by putting your
>scope probe on the crystal terminal.

The markings on the crystal are:
   22.000
   0405-0
   TKC-H
I have no idea who made it or if it is the wrong type or not.

Here is a bitmap file of the oscillator circuit (~533k).  Any
suggestions as to what type of crystal I need.

Regards,

John Ely,  W0GN