[R-390] no internal noise peak

[Dennis Wade]

Well Steve here is my two cents:

          Before setting the IF gain you need to be certain the radio is
aligned correctly, or you'll be wasting your time.  If you found a
non-spec'ed tube in there you probably should take a look at the electrical
alignment (and mechanical...couldn't hurt) before setting gain.  Setting
the gain should be one of the last things you do.

         Good luck,  Dennis


On Tue, Feb 5, 2013 at 6:37 PM, Steve Toth <stoth47 at yahoo.com> wrote:

>
>
>
>
>
> I decided to check the IF noise level adjustment on one of my R390A's per
> Chuck Rippel's technique in the Pearls  - no antenna connected, receiver
> set to 15.2 mhz, function switch to MGC, Bandwidth to 4khz, RF gain to
> MAX,, Line Meter switch to -10db, Line Gain control full CCW, then peaking
> ANT TRIM for max noise on the Line Level meter prior to setting the IF gain
> control.
>
> The antenna trim can get noise peak with an antenna connected, but cannot
> get a noise peak with no antenna connected.
>
> Looking so far in the Pearls what I've found is either "RF misalignment"
> or "a failure in the RF deck".  From looking at the schematic it would
> appear that T201-T206 need to be checked for alignment?
>
>
> I'm sure somebody has had experience with this.  Suggestions?  (I did find
> a 6CB6 in the RF amp tube socket and replaced it with a 6DC6).
>
>
>
>
>
>
>
> -- Steve
> "DON'T PANIC!" - front cover of the Hitchhiker's Guide to the Galaxy
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-- 
"If they trust you, it is an extraordinary privilege, and you simply can't
abuse it."
      - A. Alan Post  1914-2011.  California Legislative Analyst 1949-1977.

-------------------------
Dennis L. Wade
KG6ZI
Carmichael, CA