[R-390] IF Amplifier

[Larry H]

Hi Glenn,  If you are referring to the R-390A, yes there were 2 different
models.  The 1st couple years did not have trimmers on the mech filters top
and bottom and this required a different cover when they were added.  I
believe that there were also a couple other electrical changes made at the
same time (including different IF transformers).  I hope your deck has all
the important parts on it.

Regards, Larry

On Sun, Sep 15, 2019 at 5:47 PM Glenn Little WB4UIV <
glennmaillist at bellsouth.net> wrote:

> I have an IF Amplifier that was never completed.
> It is part number SM-C-343621.
> I have heard that there are two versions of the IF amplifier and suspect
> that this is the first and was pulled from the assembly line when the
> second or later version was approved.
> There is another number that I do not recognize on the IF Amp.
> FR-11-C22-C-4-26418(E), possibly a contract number.
> If there were two versions if the IF Amplifier, what were the changes?
> I would like to build this amp as if it were a kit to ensure all
> resistors are in tolerance and the capacitors do not leak.
>
> Any ideas?
>
> 73
> Glenn
> WB4UIV
>
> --
> -----------------------------------------------------------------------
> Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
> Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
> QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> "It is not the class of license that the Amateur holds but the class
> of the Amateur that holds the license"
>
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