[R-390] 7 Meg low sensitivity

[Bob Camp]

Hi

Crystals can go "weak" over time. One way is for the metalization to  
oxidize or the cement to crack (high resistance contacts). Another  
way is for the crystal blank it's self to fracture over time.

Bob
KB8TQ

On Jul 29, 2007, at 9:34 PM, Tom Elmore wrote:

>   I often wonder if crystals can go weak? I have a Collins KWS-1  
> that shows
> quite a bit of difference between the USB & LSB crystals positions.  
> I have
> checked all the caps and coils associated with the crystal  
> oscillator with
> my bridge and they check out.
>
> Thank You
> Thomas Elmore  KA1NVZ
> Anchorage, Alaska
>
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of
> Flowertime01 at wmconnect.com
> Sent: Sunday, July 29, 2007 5:10 PM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] 7 Meg low sensitivity
>
>
> Keith,
>
> After the switch contacts are cleaned with some deoxit and if the  
> problem
> persists consider pulling the crystals and doing their contacts as  
> well.
>
> Back when (68-75) we did have crystals go weak and would replace them.
> Just cleaning the contacts would not always bring a band back up to  
> par but
> a
> new crystal would fix the problem.
>
> I can believe the crystals are still going weak and causing problems.
> We just all cannot have a spare set of crystals around to swap out  
> and try
> just to see if that's the problem.
>
> If you have a one band problem ask here to see if you can get a  
> known good
> replacement to try. Postage and packing will cost more than the part.
>
> Roger AI4NI   </HTML>
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