[R-390] Crystal substitution puzzle

[JRFKE5RI at aol.com]

Have you considered the circuit loading parameters of the  "cheap" crystals 
compared to the parameters specified in the R390A  circuit?  This can 
certainly account for the difference you are  seeing.
 
John
KE5RI
 
 
In a message dated 5/14/2009 5:26:48 P.M. Pacific Daylight Time,  
rbethman at comcast.net writes:

Fair  radio still sells MANY of the crystals used in the R-390A.

I suspect  that the circuitry exceeds the ability of the "less" expensive  
alternatives.

Bob - N0DGN

David Wise wrote:
> My  R390A's Y411 (16MHz) has died.  Since it was
> cheap to try, I  bought all the wire-lead 16MHz crystals
> that Mouser stocks, five in  all, and put them in.
> They run, but every last one of them is  1.5-2.5kHz low,
> which is 50% out of spec at best.
>
> This  is five different parts, from Citizen, Fox, ECS,
> Abracon, and  Vishay/Dale, so it's not a bad part or
> a bad lot.  The original  crystal, though too weak to
> mix well, is right on.  It's a  disappointment, as the
> new ones are around $.50 each and I hoped to  open
> up an alternate supply for about half of our  second-oscillator
> crystals.  I can live with the error, but still  - what's up?
>
> Dave Wise
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-- 
Bob  -  NØDGN

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