[Hallicrafters] S-40A Sensativity

[James R Carr]

Thanks Roger.
Jim
N7FCF
  ----- Original Message ----- 
  From: Rodger 
  To: James R Carr 
  Cc: hallicrafters at mailman.qth.net 
  Sent: Sunday, January 25, 2009 4:12 PM
  Subject: Re: [Hallicrafters] S-40A Sensativity


  Jim,

  If the sensitivity is really low (best to check with a signal generator if you can): then some suggestions:

  Out of spec resistors are pretty common so I would suggest a quick check of the major dropping resistors with your ohm meter.  You can generally check the resistors in circuit and you are looking for ones that have greatly increased in value.  In Hallicrafters of that era the medium wattage voltage dropping resistors are highly suspect.  You should also check the tube socket voltages against those specified to catch any cases of extreme component shift.

  Are you sure your "new" tubes are good?  You might try subbing the originals back in place

  If you haven't done an alignment, it may well need checking and the alignment could have been thrown off a bit during the recapping.

  It is always possible to make a mistake during repairs so you might want to visually check your work to make sure a capacitor didn't end up in the wrong place.

  Good luck!
  Rodger WQ9E

  James R Carr wrote: 
    I re-capped and re-tubed a 1947 S40a, and exchanged the 6SA7 mixer for a 6SB7-Y  but sensativity is still zilch. Even with a 135 ft. dipole. 
    What do I look for next?
    Jim
    N7FCF 

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