[Milsurplus] SP600 JX-1 Witing

[k2cby]

For a good many years I have had and used a former ITT/Mackay 
Radio SP-600 JX-7 that has seen some hard use.
It must be fairly late production because the .01 uF bypass 
capacitors are ceramic. Unfortunately, the turret assembly
is in pretty rough shape, and the silver posts that engage the 
bandswitch are worn down to about half their original diameter.

I was recently able to snag on the e-place the complete RF 
chassis from a JX-1. The radio was an early one -- s/n 5711. 
Mechanically, it is in excellent condition but it's full of 
"black beauties" (one of them completely split).

While in the process of re-capping with ceramics, I discovered that 
the wiring of the RF stages does not correspond exactly with the 
available manuals or my current JX-7. Not only are some of the 
ground points different but there are some extra components.

Specifically, there is an extra .01 bypass capacitor and series 
resistor in the screen circuit of V2 (attached to the last pin
of the third (V2) tie strip), and there is a series capacitor between 
R21 (Pin 6 of S1C) and pin 7 of the mixer (V5).

Does anybody have a print on which these changes appear?

Were these improvements, or did Hammarlund merely eliminate some 
unnecessary parts?   

Miles B. Anderson, K2CBY
16 Round Pond Lane
Sag Harbor, NY 11963
Tel.: (631) 725-4400
Fax.: (631) 725-2223
e-mail: K2CBY at optonline.net