[AMRadio] Ghost from the 30's

[Rob Atkinson]

I have been working on an Admiral AA5 receiver built in 1951 or 52 and
has the larger octal tubes.   I have it working FB but it, and other
AM bc band receivers at my QTH have a curious modulated hum problem
below around 900 to 1000 kc.  There is 120 cycle hum pickup that seems
to mix with the local oscilator and received station into the 455 kc
IF.  I know it is not any one rx because I get it even with my newer
battery powered GE Superadio.  I am guessing there is a ground loop
somewhere in the house but if anyone else has had this problem I'd
like to know what the fix was as it might save me a lot of time by not
pursing dead end leads.

p.s. Charlie, have not seen any prints in mine but it has a nice brown
bakelite case--my late 50s ones are plastic.

Rob
K5UJ

On Thu, Jun 2, 2011 at 11:30 AM, CL in NC <mjcal77 at yahoo.com> wrote:
> I was working on a Motorola All American 6 AM BC RX, this from the late 30's or early 40's that had the additional RF amp stage for the 6th tube.  The bakelite cabinet had a chunk knocked out of it, and I was positioning it to see how it would slide back in the gap when it had epoxy on it.  On the inside of the broken piece, were the fingerprints of the person who painted the cabinet.  Not starkly evident, but ghostly visible in the same original eggshell color as the outside of the cabinet.  The prints were very small, fairly sure it was a woman, as I think child labor laws were in effect by then.  You have all opened up an old rig and seen fingerprints left on chassis from the oils on skin.  It's like a "Kilroy was here" calling card inadvertently left for the owner of the old treasure to wonder about the folks who have handled things over all the years.
>
> Charlie, W4MEC in NC