[Hallicrafters] SR-150 Tuning

[Ronald Oberloh]

I have not spent much time in the actual alignment yet so maybe that
will fix the problem.  I just went through measuring all the tube pin
socket resistance's which was interesting. Actually I am restoring two
SR-400's and have measured both and have  compared them to each other
and to the manual. Found about 7 resistors way out of tolerance and
quite a few places  where the manual was totally wrong.  It seemed to
me that nobody ever sat down and did a simple resistor calculation to
derive the value but instead sat down with a voltmeter and measured
them instead.  In many cases unless all the controls are set to the max
or min condition the results are all over the map  and the manual
wasn't specific about where they should be.  Then there was V6 pin 2
which has a 330 ohm resistor to ground  and the resistive chart say 220
ohms.  


Looks like the next step is alignment. 



Ron  WA0KDS 






   






Yardleyite at aol.com wrote:


  Greetings all,
                   Interesting point! I had the same situation with my 
SR-2000 "Hurricane" with low receiver output, and realized that I could get power 
out of the 8122's at a few different points. I thought I had a problem in the 
pi-net. 

Upon further inverstigation, I tuned it up per the instructions in the manual 
and I got good power output and strong receiver performance as well. I must 
have had it off resonance.
               Regards,
                           Joe Cro N3IBX


In a message dated 1/5/04 10:43:14 AM Eastern Standard Time, wa0kds at yahoo.com 
writes:


  
  
    I am in the process of restoring an SR-400 and have noticed the same 
thing.  Is this normal for the Hallicrafter transceivers?  If is is has 
anyone modified the circuit to correct the problem or know what might be 
causing this. If it was a little off it would not bother me but it  is a 
long way off.  If this is not normal then what might be the problem?   I 
have not checked the schematices but knowing a little bit about other 
Hallicrafter products I expect the SR-150 and SR-400 might have a lot of 
circuit in common.

Thanks
Ron   WA0KDS



John N. Schwartzberg wrote:

    
    
      
        Hey Gang -

I dusted off my radio bench, then the SR-150, to warm up the shack.  
I noticed the following while tuning it up on both 20 and 40 meters:

With a resonant antenna load, peaking both the pre-selector tuning 
and the final output tuning for maximum indication on either an 
external watt-meter or the internal meter results in relatively low 
receiver sensitivity.  I can then increase the receiver sensitivity 
with the pre-selector tuning, but at the expense of output.  The 
manual includes the following tuning instructions:

"Adjust the RF Level control until a small indication is seen on the 
S-meter.  In the transmit mode, the S-meter indicates the relative RF 
voltage.  Adjust the FINAL TUNING control for maximum output and then 
adjust the PRESELECTOR for maximum output indication.  Adjust the RF 
LEVEL control as required to keep the S-meter below S9, while tuning 
the PRESELECTOR."

Is it "normal" to then be able to peak up the received signal using 
the PRESELECTOR control after this tuning procedure?  I don't recall 
that being the case in the past, but I can't honestly say that I've 
ever checked it.  I follow the prescribed tuning procedure, and go.  
For some reason today, I adjusted the preselector some time after 
tuning thinking the received signals were kind of low, and discovered 
that I could peak them up, but lost about 1/4 to 1/3 of the output 
indication.

Has anyone else observed this on their SR-150, or does the collective 
brain trust have any thoughts?

Thanks... and Happy New Year (or is that Hallicrafter's New Year?)

73,

John

N0GII

Denver, CO
        
      
    
  
  



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