[Yaesu] FT-990 frequency stability

[Harris Ruben]

This is the note I got from Yaesu:

Hello Harris
If the frequency shift occurs on all bands and all modes then I would say
that you have an unstable reference oscillator. Normally you want to replace
the crystal and the trimmer capacitor. If you would like to do the repair
yourself you can contact our parts department at 562-404-2700 ext. 351 or by
email at yaesuparts@vxstdusa.com you can order the following parts.

Crystal		X4001 	Part number H0102990	$6.74
Trimmer capacitor TC4001	Part number K91000261	$0.52

Both of these parts are located on the Local Unit
You will have to adjust the frequency of the oscillator when finished either
with a frequency counter or zero beat to WWV on 10 MHz lower side band. Let
me know if you have any questions.

Best Regards,
Jerry Darby, N6UME
Technical Support
Amateur Products Division
Vertex Standard USA
(562) 404-2700 Ext. 244