[Boatanchors] National NC-140 receiver? (and a long ramble)

[Al Klase]

Phil,

I haven't worked on this particular radio, but I just took a pretty good 
look.  All the doc's I found were fuzzy but usable.

I stitched and tweaked the 3 page schematics, and stitched the two pages 
of alignment instructions.  I'll send these in an off-list email.

National used all the tricks to extract maximum performance out of 9 tubes.

It has a 230KHz final IF, just one stage, that is regenerative to get 
narrow selectivity. (Q-multiplier - SELECTIVITY control)

The set is double conversion on the upper three bands to get decent 
image rejection with just one RF stage.

Align carefully.  RTFM! :-)

If it has paper capacitors, they're all suspect.

Good luck,
Al

On 10/19/2017 9:14 PM, Phil wrote:
> ...........But this is about the NC-140.  I have the basic Instruction 
> manual here, schematic and a sheet showing alignment, all a bit 
> blurry.  May try to find a manual download on line.
>
> I've worked on a LOT of tube radios since I got my start around 1953, 
> but my real question is this. . .
>
> Does the NC-140 have any "gotchas" that I should watch for, or is it 
> pretty straight forward??
>

-- 
Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/