[Hammarlund] HQ-180 Mods

[RAY FRIESS]

Thanks for the heads up.   Have had my license since I was 16, so I should be able to summon up enough ability and
smarts to try this.   50 years as a ham ... I should have learned something, but it's always nice to have the advice and
thoughts of other old timers...  HI HI.



> From: k2cby at optonline.net
> To: hammarlund at mailman.qth.net
> Date: Tue, 24 May 2016 16:32:28 -0400
> Subject: [Hammarlund] HQ-180 Mods
> 
> Ray,
> 
> You may have less trouble than you think.
> 
> You say that the static is present even when the volume control is all the
> way down.
> 
> This means that the source of the noise is somewhere downstream of the audio
> gain control.
> 
> The only things in that neighborhood are the audio amplifier and the output
> stage.
> 
> Take a rather large (.01 to 0.1 uF) capacitor. Connect it between the
> control grid of the output tube and ground. If the noise goes away, the
> problem is somewhere between the volume control and the grid of the audio
> output tube.
> 
> My bet would be a leaky coupling capacitor between the plate of the audio
> amplifier and the grid of the output tube.
> 
> If that is OK the next place to look is the cathode bypass of the audio
> stage.
> 
> /Miles, K2CBY
> 
>  
> 
> Miles B. Anderson, K2CBY
> 16 Round Pond Ln.
> Sag Harbor, NY 11963
> 
> k2cby at optonline.net
> 
>  
> 
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