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Well Steve, got a chance to take a look last night and sure enough, .0033 on
schematic and in xcvr. Imagine that!
Jay/KM6VX
-----Original Message-----
From: Steve Ellington N4LQ [mailto:N4LQ@iglou.com]
Sent: Tuesday, March 02, 1999 3:22 PM
To: TenTec@Contesting.com
Subject: [TenTec] Century 22 Error
Recently I acquired a nice Century 22. This rig uses an audio filter between
the detector and audio amplifier for all of it's selectivity. When I
advanced the "filter" control for maximum selectivity, I noticed that the
peaked or resonant frequency of the filter was very low, around 350hz. This
did not correspond to the manual's specification of 750hz and made for
uncomfortable listening.
Check the schematic of the RCVR/CONTROL ASSEMBLY and observe the 4 pole
audio filter across the top. Mine shows an LM3900 with 8 capacitors, all
being .0033uf. This seemed strange since the Delta 580 and Omni D use the
same component values yet the capacitors are all .0022uf. The ARRL Handbook
also indicates the caps should all be .0022uf. Now to see what was really
inside the rig. Sure enought, .0033uf!
I removed all 8 capacitors and replaced them with .0022uf. Now the filter
peaks beautifully at 750hz. Turning the filter to max results in a clean
750hz tone on cw notes.
I would appreciate some feedback on this. What does your manual show and
what is actually in your rig? Do other C22's have the correct value?
73 Steve Ellington N4LQ
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<TITLE>RE: [TenTec] Century 22 Error</TITLE>
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<P><FONT SIZE=3D2>Well Steve, got a chance to take a look last night =
and sure enough, .0033 on schematic and in xcvr. Imagine that!</FONT>
</P>
<P><FONT SIZE=3D2>Jay/KM6VX</FONT>
</P>
<P><FONT SIZE=3D2>-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>From: Steve Ellington N4LQ [<A =
HREF=3D"mailto:N4LQ@iglou.com";>mailto:N4LQ@iglou.com</A>]</FONT>
<BR><FONT SIZE=3D2>Sent: Tuesday, March 02, 1999 3:22 PM</FONT>
<BR><FONT SIZE=3D2>To: TenTec@Contesting.com</FONT>
<BR><FONT SIZE=3D2>Subject: [TenTec] Century 22 Error</FONT>
</P>
<BR>
<BR>
<P><FONT SIZE=3D2>Recently I acquired a nice Century 22. This rig uses =
an audio filter between</FONT>
<BR><FONT SIZE=3D2>the detector and audio amplifier for all of it's =
selectivity. When I</FONT>
<BR><FONT SIZE=3D2>advanced the "filter" control for maximum =
selectivity, I noticed that the</FONT>
<BR><FONT SIZE=3D2>peaked or resonant frequency of the filter was very =
low, around 350hz. This</FONT>
<BR><FONT SIZE=3D2>did not correspond to the manual's specification of =
750hz and made for</FONT>
<BR><FONT SIZE=3D2>uncomfortable listening.</FONT>
</P>
<P><FONT SIZE=3D2>Check the schematic of the RCVR/CONTROL ASSEMBLY and =
observe the 4 pole</FONT>
<BR><FONT SIZE=3D2>audio filter across the top. Mine shows an LM3900 =
with 8 capacitors, all</FONT>
<BR><FONT SIZE=3D2>being .0033uf. This seemed strange since the Delta =
580 and Omni D use the</FONT>
<BR><FONT SIZE=3D2>same component values yet the capacitors are all =
.0022uf. The ARRL Handbook</FONT>
<BR><FONT SIZE=3D2>also indicates the caps should all be .0022uf. Now =
to see what was really</FONT>
<BR><FONT SIZE=3D2>inside the rig. Sure enought, .0033uf!</FONT>
</P>
<P><FONT SIZE=3D2>I removed all 8 capacitors and replaced them with =
.0022uf. Now the filter</FONT>
<BR><FONT SIZE=3D2>peaks beautifully at 750hz. Turning the filter to =
max results in a clean</FONT>
<BR><FONT SIZE=3D2>750hz tone on cw notes.</FONT>
</P>
<P><FONT SIZE=3D2>I would appreciate some feedback on this. What does =
your manual show and</FONT>
<BR><FONT SIZE=3D2>what is actually in your rig? Do other C22's have =
the correct value?</FONT>
</P>
<P><FONT SIZE=3D2>73 Steve Ellington N4LQ</FONT>
</P>
<BR>
<P><FONT SIZE=3D2>--</FONT>
<BR><FONT SIZE=3D2>FAQ on =
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<BR><FONT =
SIZE=3D2>Submissions: &nb=
sp; tentec@contesting.com</FONT>
<BR><FONT SIZE=3D2>Administrative requests: =
tentec-REQUEST@contesting.com</FONT>
<BR><FONT =
SIZE=3D2>Problems: =
=
owner-tentec@contesting.com</FONT>
<BR><FONT =
SIZE=3D2>Search: &n=
bsp; <A =
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