[Heathkit] Need SB-303/401 Expert Help Needed.

[wa3fiy at radioadv.com]

Sounds to me like it be carrier balance.  That is the carrier is not completely 
balanced.  The procedure for balancing the carrier is in the manual.

Please let us know what you find.

73,

-Lee-
WA3FIY


On 13 Oct 2006 at 21:50, OTAKEBI at aol.com wrote:

>  
> I have been working an SB-303 SB-401 combo.
> What I thought was mic hum is not.
> I hooked up another receiver to hear my own signal and I can hear what  seems 
> to be a tone
> that I can only describe as a spotting tone type of noise when I dead  key 
> the mic.
> The noise is raspy with a tone that changes frequency as I tune  the 
> transmitter with the tuning knob.
> If I leave the SB-303 on and unlock the transmitter (SB-401) to make it a  
> stand alone transmitter the noise is still there when I dead  key.
> If I talk the SSB signal is clear with no flat topping on the  scope.
> I have tried different mics and I have tried to use no mic but just  shorting 
> the relay to ground.
> Noise still there.
> I have peaked and nulled the carrier on the board as per the manual with an  
> RF probe.
> I have checked all tubes with known good subs and with a tube tester.
> Set is putting out full output and but for the noise it works  great.
> How can I track down such a generalized noise in order to fix the  problem?
> Could an expert on this weird problem lead me to solving it.
> This does not seem to be a bad ground problem.
> Any help would be great since I am stuck and need new ideas.
> Thanks,
> Dan/N4VET
> 
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