[R-390] IF Modifications - Teledyne 3399

[Larry H]

Hi  Gary,  It's making a little more sense now, but v509a pin 2 needs a res
to ground and v506a pin 1 needs B+.  And the res/cap network around s107
needs clarifying.

Regards, Larry

On Sun, Jan 29, 2023 at 3:17 PM <gary.biasini at shaw.ca> wrote:

> Larry, and previously, Renee,
>
>
>
> Thanks for your comments.  I reviewed the drawing again against the wiring
> in the module and realized that I had missed a number of items.  A revised
> schematic, hopefully complete this time, is attached.
>
>
>
> Regards,
>
>
>
> *From:* Larry H <larry41gm at gmail.com>
> *Sent:* January 25, 2023 12:24 AM
> *To:* gary.biasini at shaw.ca
> *Cc:* R-390 at mailman.qth.net
> *Subject:* Re: [R-390] IF Modifications - Teledyne 3399
>
>
>
> Hi Gary, It looks like it converts V509A to an  AGC amp and removes V506A
> from the AGC time constant circuit.  But, the schematic still has some
> deficiencies to make it work.  V509A pins 1 and 2 need to be separated and
> pin 2 needs a resistor to set bias.  V506A still needs B+ to it's plate for
> the meter to work.
>
>
>
> Regards, Larry
>
>
>
> On Mon, Jan 23, 2023 at 9:35 AM <gary.biasini at shaw.ca> wrote:
>
> Sorry folks,  I neglected to add the break in the C547 connection and the
> addition of the new C547 connection.  Attached is a corrected PDF
> schematic.
>
> Regards,
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> On
> Behalf Of gary.biasini at shaw.ca
> Sent: January 22, 2023 9:01 PM
> To: R-390 at mailman.qth.net
> Subject: [R-390] IF Modifications - Teledyne 3399
>
> Good evening,
>
>
>
> After some procrastination, I finally traced all the modifications that I
> could see on the IF sub-chassis of one of my R-390a receivers.  I attach a
> marked up schematic showing the changes.  This radio was in the worst shape
> of the R-390a radios I have had and I have spent much time bringing it back
> into shape.
>
>
>
> Unfortunately, I cannot advise what effect these modifications appear to
> have (they look like SSB and AGC modifications) since I cannot get the
> radio
> to operate.  I had to stop troubleshooting as I blew all the 1/8 amp fuses
> that I had and am waiting for some to arrive.
>
>
>
>
>
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