[R-390] Crystal substitution puzzle

[Roy Morgan]

On May 15, 2009, at 12:25 PM, David Wise wrote:
...  Out on the net there's an analysis
> of series- vs parallel-mode crystal operation

Can you post the URL?  Thanks.

> ... a series-rated
> crystal operated inductively will run above rating,
> not below.

I assume that you mean above rated frequency, and inductance in  
series.  It could well be that inductance in series has the opposite  
effect as capacitance in parallel.  The R-390 circuit, we can assume,  
has more capacitance in parallel with the crystal than the new  
crystals are meant to have.

(No, I have not puzzled this out by analyzing the equivalent circuit  
of the crystal and all that.)

Roy

Roy Morgan
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