Steve, the mixer has a balance trim pot. Maybe someone was trouble
shooting a problem on 80 M and when he "tweaked" to pot the radio came
alive. I imagine with significant unbalance and with the gain of the
mixer there would be enough 5Mhz drive.....maybe. :-) I'm anxious
to hear what Rick finds but it may be a little while before that busy
chap can get to it.
73,
-Lee-
------ Original Message ------
From: "Steve Hunt" <steve@karinya.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: 9/6/2016 2:01:36 PM
Subject: Re: [TenTec] rick's recalcitrant 515
Rick,
That was the only option I could come up with that met the observed
symptoms!
However, I dismissed it because I didn't think enough of the
5MHz-5.5MHz PTO signal would make it through the MC1496 PTO/XTAL
balanced mixer to provide a viable local oscillator. On 20m - when they
use the PTO signal directly for the Local Oscillator - they switch it
directly to the LO buffer, completely bypassing the MC1496.
It'll be interesting to hear if the rig does tune "the wrong way" -
that would be further evidence that the LO is wrong. A quick check if
you hear CW signals at the 'phone end of 80m and vice-versa might
confirm it.
73,
Steve G3TXQ
On 06/09/2016 06:33, rick@dj0ip.de wrote:
THIS MAKES SENSE! It is the only plausible thing that can be going on
because from the logic standpoint, everything is switching as it
should.
That will be an easy fix, once I can make time, clean the workbench to
make
room, etc.
73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
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