Fw: [R-390] Below 8mhz problem

[Jim Temple]

Hello to the list,

Success!!  It was in the 1st oscillator circuit where I found the problem,
but the fix I did not expect.

I had originally checked and reworked all the grounds in the RF deck......I
thought.

Below T207, surrounded by components, is another ground point that also
anchors T207 to the deck.  The deck is coated with a shellac of some sort,
and I found the ground sitting on the shellac, finger tight.  I removed the
shellac and tightened the ground, and the radio sprang to life.

Very strong cal signal above and below 8mhz.  Also, the variable IF is
hearing just fine now.

It goes to show that all those trees in the forrest can get in the way of a
simple fix.

Thanks to all who offered their time and expertese in assisting me with this
fix.  I also know that those who may have expertese in other areas would
have assisted if it was needed.

Thanks again.

Regards,

Jim Temple
73, KF4ICZ

----- Original Message -----
From: "Jim Temple" <jetemp01@athena.louisville.edu>
To: <r-390@mailman.qth.net>
Sent: Tuesday, January 22, 2002 9:34 PM
Subject: [R-390] Below 8mhz problem


> Hello to the list,
>
> As an update, I have found that E209, before the 1st mixer has low
voltage.
> It should be approx -6.5 volts, and it actually is -.85.  Measured with a
> 1meg resistor it is -.76.
>
> The other RF deck test points have good voltage.
>
> The faint cal signal below 8mhz is the same on all bands below 8mhz.  This
> prevents me from hearing the signal generator signal needed to calibrate
the
> variable IF section.  The cal signal on all bands 8mhz and above is strong
> and loud.
>
> I have received suggestions to:
>
> 1.  Check all the appropriate coils, switches, antenna relay, and anything
> that plugs in or wipes, before the 1st mixer v202, due to corrosion
> suspicions because of the "massacre" origion of the radio.
>
> 2.  Check HR202 crystals, especially 17mhz.
>
> 3.  Inspect circuitry between 1st mixer V202 and 1st crystal oscillator
> v207.
>
> The crystal seems to be OK, because I purchased a spare HR202 with the
> radio.
>
> I have substituted the 6c4 and 5654 tubes V202 and V207 with no change.
>
> Thanks for the suggestions, and tomorrow I will get deeply into the above
> suggestions.  So long for now.
>
> Regards,
>
> Jim
> 73, KF4ICZ
>
>
>
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