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Skyrider March 22nd 06 04:35 AM

Hallicrafters S-20R alignment
 
Andrew,

Ah...that is something I had not thought of...considering that the
trimmer and padder for band 3 do affect band 2 (one item I had
neglected to mention in my previous posts, and if memory serves they
shouldn't oughta do that) and vice versa....


Skyrider March 23rd 06 05:04 AM

Hallicrafters S-20R alignment
 
A follow up....

Found the problem, and thank you for all your input.

The problem turned out to be none of the things anyone suggested, but
Andrew came closest when he mentioned the band switch.

Here is the story:

Looking at the band switch, I noticed a wire on a grounded terminal
which had a somewhat cruder solder joint than those on the other
terminals. This wire was 1/2 of C-38, a coupling (listed in the manual
as a neutralizing) capacitor consisting of a couple wires twisted
together. This "capacitor" was supposed to couple from the band 3
oscillator coil to the mixer, instead the oscillator side was grounded.
And what about the wire which had been attached to the oscillator? It
was attached to the band 2 oscillator coil. Snipped out the ground
wire, snipped the wire from the band 2 coil and re-wound it with the
wire going to the mixer, and now all is well.

I had looked over the circuit before, but apparently I missed this
"modification". Now I have to wonder....what was it that the person
making this modification was trying to achieve?



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