[Milsurplus] crystal has lost activity?

[Greg Werstiuk]

As John and Robert point out indirectly and jointly, what you surmise is
basically true for the old FT-243 and similar crystal assemblies where the
crystal was held in place by pressure plates.

In modern crystals, metallic electrodes are deposited on the crystal element
itself so cleaning and contact pressure are not applicable.  The cans are
hermetically sealed so they shouldn't "lose activity" over any reasonable
period of time.  However, modern crystal elements are much thinner and far
more fragile (not unreasonably so) than those of the mid-1900s and more
subject to damage by shock.  A failure is more likely to be a broken element
rather than anything which could be fixed.

- Greg

> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net 
> [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of john 
> p hutchins
> Sent: Sunday, May 13, 2007 9:25 PM
> To: Milsurplus at mailman.qth.net
> Subject: [Milsurplus] crystal has lost activity?
> 
> Group -
> 
> Now educate me please.  A crystal is a rock,. that vibrates 
> when electrical stress is applied through metal plates at 
> particular angles to the crystalline grain?
> 
> I have seen many of these kinds of statements:
> "After years it is possible that the  crystal has lost activity."
> 
> To stop a crystal form working would be corrosion forming on 
> the metal plates or loss of conduction to the crystal surface. 
> 
> Any of combinations of these conditions could be rectified by 
> cleaning, adjusting contact pressure on crystal surface, 
> repairing conductive 
> path?   So with the correct tools any crystal could be 
> "fixed." to operate?
> 
> Am I off base?
> 
> Thanks
> Hutch
> 
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