[600MRG] restoring old crystals ??

[Neil Klagge]

Ken, that was a good step by step set of instructions. Thank you. As I read
thru it, and some of the other replies I got, it brought back my memory of
my early experiences with this.

Thanks to all who replied to my question about rejuvenating a quartz
crystal.

Neil Klagge, w0yse, Utah

On Tue, Feb 5, 2013 at 4:53 PM, Kenneth G. Gordon
<kgordon2006 at frontier.com>wrote:

> On 5 Feb 2013 at 16:23, Neil Klagge wrote:
>
> > Thanks Ken. Ur comment "*It would be an excellent cleaner for the
> > crystals*" is just what I want to use it for. It might just activate
> > the crystal enough to oscillate.
> >
> > Neil
>
> Neil, I am assuming you are trying to reactivate FT-243 crystals: if so,
> there
> are a couple of other things besides CRYSTAL cleanliness you should think
> about.
>
> First, the two metal plates between which the crystal is held have raised
> bits
> at the four corners: those corners should contact the crystal in such a way
> that there is a small air-gap between the two metal plates and either
> surface
> of the crystal. Sometimes, folks have put those back in backwards, not
> realizing there are "lands" at each corner.
>
> Secondly, those metal plates must be totally clean. I use alcohol to clean
> those and handle them with clean tweezers.
>
> Thirdly, the entire interior of the holder must be as clean as a whistle.
> Alcohol
> works well here too.
>
> Fourthly, there should be two small thin copper plates which are connected
> to the pins. These usually are clamped when the crystal holder is closed up
> to the two metal plates mentioned above.
>
> Lastly, there should be a piece of flat rubber between the crystal holder's
> cover (the part with the three screws in it) and the spring that is
> supposed to
> press against the top connector and metal plate. There should be no
> electrical contact between either metal plate and the outside of the
> crystal.
>
> I have also seen some FT-243 holders in which the copper connectors are
> actually not making contact inside the pins. Sometimes, these can be
> resoldered.
>
> However, the most important factor is that the crystal itself must be
> scrupulously clean. You can use an old toothbrush and dishwashing
> detergent to scrub the heck out of it without hurting it. Get all the dirt,
> finger-grease, solder, flux, or anything else that is not "crystal" off
> and out of
> there.
>
> Good luck.
>
> Ken W7EkB
>
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