Found Collection

I have a Wesinghouse H-104B bc/sw radio. Two strong local stations appear all
over the dial. Not 455hz apart. Is this an alignment problem? Or maybe antenna?
other stations are in there too but not as strong. I have done tube
substitution and recapped the set. Alla nd any ideas will be appreciated.
Eric.Thanks

Eric:
Interesting problem.I suspect that the stations must be very strong-might be
getting directly into the IF if the signals are not tuneable.Could be a missing
shield,could be a problem in the front end reducing it's selectivity.I assume
they go away when the local oscillator/mixer is disabled?
Best,
Mike Zuccaro
Antique electronic repair.

  Thanks for responding Al. Maybe it is a shield. I dinked with the IF cans a
bit and got some weaker stations to be much clearer but still the two strong
local stations are all over the dial,.less bleed thru though.  I replaced the
40 mfd's, with 47mfd, 20mfd with a 22, and a 5mfd with a 4.7 mfd.
  I'll keep plugging away at it. Eric. Again thanks.

I messed with the set a bit and can pickup distant stations fairly well but
still have the
two strong local stations slipping in all over the dial. I will keep plugging
away.

Worked like a champ afterwards.

Only thing I could figure was that somehow the assembly had gotten
contaminated over time.

Good Luck.

Dave

John

The symptoms are:  You get a few stations at the right spots on the dial
(or sometimes no stations at the right spots), and you weakly get a few
strong local stations that tune in very broadly (30 to 100KC wide each).

What's happening:  The local oscillator is dead, either all over the
dial, or just over one part of the dial.   On the spots of the band where
the oscillator is working, you tune in stations normally.
Where the oscillator dies, the converter tube (12SA7, 12BE6) loses its
grid bias and it is now biased on a non-linear operating point.  This
lets it act as a (poor) diode and/or plate detector.   You now have a
poor crystal set, with only the RF tuned circuit for selectivity.
Somehow the audio gets passed on, perhaps modulating the weak background
noise.

So when you see these symptoms:  very weak reception, signals tuning very
broadly, look for a dead oscillator.  This is often caused by a weak
converter tube, or corroded oscillator coil, or a oscillator grid
resistor that has drifted way up in value.

Regards,

George

John