[Collins] {Collins} R-388/51j4 crystal filter

[Bill Carns]

I would add something here.. Having worked with crystals in my career, you
should know that mechanical shock tends to move the crystal in frequency the
same direction that aging does.  This effect is cumulative and irreversible.
Whenever you "tap" a crystal for some reason, be sure and do it with
something soft like the end of a pencil eraser.  Sharp raps are bad.

Bill

-----Original Message-----
From: Collins [mailto:collins-bounces+wcarns=austin.rr.com at listserve.com] On
Behalf Of Richard Knoppow
Sent: Tuesday, September 17, 2013 2:38 PM
To: Grant Youngman; Collins at listserve.com; <collins at mailman.qth.net>
Subject: Re: {Collins} R-388/51j4 crystal filter




-----Original Message-----
>From: Grant Youngman <nq5t at tx.rr.com>
>Sent: Sep 17, 2013 11:43 AM
>To: "Collins at listserve.com" <collins at listserve.com>,
"<collins at mailman.qth.net>" <collins at mailman.qth.net>
>Subject: {Collins} R-388/51j4 crystal filter
>
>I have my 51J4 aligned and working well, with a good (on the third try --
thanks, Fern!) 3.1 KHz mechanical filter, Lankford SSB mods, and my Sherwood
SE-3 modified to be switchable between 455 and 500 KHz IFs.
>
>Except for one thing ... sometimes, not all the time, when I turn on the
crystal filter to any position the radio sounds like the "divine wind" has
started to blow.  A significant noise level appears in the output, somewhat
affected in character by the phasing control.  Before I tear into the radio
again, I wonder if anyone has encountered something like this and has a clue
where to point the finger?  There isn't anything added to the signal path
except for the crystal itself and a parallel 10 pf cap in position 1.  Any
thoughts?  A grounding issue maybe?
>
>Thanks .. Grant NQ5T
>
>Sent from my iPad

     My understanding of the SE-3 is that its completely outboard.  Do you
get the same effect with the normal detector?  
     The easiest thing to do is to squirt some contact cleaner into the
crystal switch. You can reach it through the left hand (facing the receiver)
hole in the top of the filter can. If this doesn't clear the noise you will
have to remove the filter can and inspect the works. Its possible its a bad
crystal but I would investigate the soldering, etc.  Crystals seem to be
difficult to find and a new one would be very expensive. I once asked
International Crystal about this and they did not seem interested. 
     You can probably reach the crystal through one of the holes in the can
and tap it to see if that makes any difference. 



--
Richard Knoppow
dickburk at ix.netcom.com
Los Angeles, CA, USA
*** You are subscribed to Collins as wcarns at austin.rr.com. If you wish to
unsubscribe, or modify your preferences please visit
http://mailman.listserve.com/listmanager/options/collins/wcarns%40austin.rr.
com or to learn more about our list visit
http://mailman.listserve.com/listmanager/listinfo/collins ***


-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.3408 / Virus Database: 3222/6674 - Release Date: 09/17/13