[Hallicrafters] Oscillating SX-16

[Mike Everette]

How many caps have you replaced so far?

It sounds as if the push-pull audio stage is
oscillating, which explains why the noise stops when
you pull one of the tubes.

I think this could be a power-supply related issue. 
If the electrolytics are shot (and they are, if they
are very old), and the cathode bypasses are also shot,
this can cause the problem you describe.

So, if you have not already done this:

Stick in some new electrolytics, both filter and
bypass; or clip-lead them in -- disconnect the old
caps or you're liable to have one of them short out
and zap your power transformer! That'll REALLY ruin
your day -- and then see what happens.

It may work, at least after a fashion.  

Then, go to the next step: Bite the bullet and replace
ALL the paper caps.  You will more than likely have to
replace more than half of the resistors as well,
because they have changed value radically.

"Working," eh?

Remember, this radio is old enough to be drawing
Social Security.  It ain' gotta work no mo' so
"you've" gotta "work on" it! 

73

Mike
WA4DLF




	
		
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