[Hallicrafters] SR-400 schematic information

[James Liles]

Hi Paul:

It is the suffix on the lower right edition number of the schematic.  I have seen some notes from Bob Orwin, the chief engineer at Hallicrafters that indicate he was a kind of referee between two groups that were working to create a marketable upgrade for the SR-400.  One group represented the Cyclone II which culminated in level “F” and the other the SR-400A.  The SR-400A group I believe were Northrop engineers and the Cyclone II old Hallicrafters.  The decision was purely financial.  The Cyclone II level “F”upgrade was judged impractical to do in the field and probably would not have marketed well, so the SR-400A got the carrot.  For years Bob Orwin lamented the Cyclone II was the better of the two.  He was half right.  They had succeeded in correcting the spur and harmonic problems that were so evasive in levels “A” through “E” but the SR-400A was a huge financial success; although it to, had it’s share of minor bugs.  Thus the Cyclone II was relegated to history.  

I have one of the modified SR-400 radio’s that were the SR-400A prototypes.  the only mod to the physical radio is the cover for the final cage had to be reshaped to accommodate the 6KD6’s and of course the extra parts.

Note the SR-2000, SR-400, and SR-400A were a superb and fitting way to end the era of tubed radios for Hallicrafters. 

Kindest regards Jim K9AXN  
   

From: Paul Kraemer 
Sent: Wednesday, July 11, 2012 5:31 PM
To: James Liles 
Subject: Re: SX-117 information

James
Thanks so much for all the great contribution on the SX-117
How is C, D, E identified on the 400 schematic. I can look at my manual to see if it is one of those.
Paul
  ----- Original Message ----- 
  From: James Liles 
  Good evening Paul:

  I gathered some doc that will help you to understand the genesis and progression of the SX-117 design.

  You will find all five schematics, “A” through “E” in the schematics section of www.k9axn.com.  Also, you will find the design specs, EC notes, and some miscellaneous stuff, same site service notes for SX-117.

  It’s there for anyone to upload and enjoy.  Any questions, send a note.

  BTW, I’m still looking for the “C” through “E” schematics for the SR-400 ----- anyone?  Someone must have them! 

  Kindest regards Jim K9AXN