[Hallicrafters] SX-28 Questions

[HallicrafterSX28 at aol.com]

Hi
The open primary in the ANL transformer won't affect perforamce other  than 
an in-operative variable noise limiter.However the shunt type NL will still  
work as it doesn't depend on that particular transformer.

The whole  purpose of the exercise is to align the IF circuits to the 
frequency of the  particular XTAL in the rcvr .The instructions in the manual have 
been a source  of frustration for many people aligning an SX-28 for the first 
time.If you're  doing this for the first time,I'd suggest (to keep your life 
simple) to switch  to SHARP IF , inject a 455KHz signal into the mixer and align 
T1,T2,T3 (lower  screw only) and trimmer C31(If memory serves me right) for 
peak response.
You'll have 3 degrees of IF selectivites and still  enjoy the  rcvr.
Good Luck
AMK"Nick"

In a message dated 10/12/2008 9:24:17 AM Pacific Daylight  Time, 
joeconnor53 at yahoo.com writes:
Thanks to the group, individually and  collectively, my SX-28 is really 
starting to shape up. I've replaced all the  paper caps (including the notorious 11 
in the RF deck) as well as out-of-spec  resistors. Sensitivity is now 
excellent (at least below 12 mHz). 

I have  two more questions.

1. The ANL transformer (T-5) has an open primary.  Until I can get that 
apart, is it likely to affect performance?

2. The IF  alignment puzzles me.

a. the first step is to  adjust T1, T3 and only one screw on T2. I understand 
that.  

b. The next step is to turn on the BFO and  adjust to Crystal Broad. It says 
to adjust the top screw on T2 while varying the  signal generator frequency 
until I get two maximums and a dip between them. It's  described as a swishing 
note, as opposed to a sharp crystal note. This is the  part I don't understand. 
Am I using a modulated signal through my generator? Can  someone explain this 
step to me? I assume it's designed to adjust the IFs to the  crystal 
frequency. 

As always,  thanks.

Joe Connor




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