[R-390] R390A- Intermittent sensitivity variation

[Charles P. Steinmetz]

Eric wrote:

>it seems that my problem was in fact caused by aged silver
>mica capacitors.
>
>Since Z206-1 and Z206-2
>have identical capacitors and coils , I decided to swap over these
>transformers.  After realignment at 17.6 and 30.4 MHz,   sensitivity was
>restored, and no more intermittent behaviour!

Before you can properly conclude that the mica caps in Z206-1 caused 
the problem, you would need to swap the transformers back and have 
the problem reappear, then go away again when you replaced just the 
caps (even then, you couldn't absolutely rule out soldering, broken 
wires at the joints, etc., etc.).  Right now, you just have an 
intermittent problem that appears to have gone away during 
troubleshooting -- like so many do with old equipment.

Best regards,

Charles