[Hallicrafters] SR-2000 post production change

[Jim Liles]

Hi Carl:
Thanks for your response.  This problem is not a lead tin crystallization 
problem.  It is a cross section problem where a variable cap tab connector 
is far too small.  We simply quadrupled the cross section area of the tab 
and  the heating ceased to occure.  It was heating of the inadequate joint 
that melted the solder.  The cap has three gangs and only one exhibits the 
malady.  We used silver solder to restore the connections for added 
insurance.  What I probably did not convey is that if you have an SR-2000, 
it will absolutely have this problem to some degree.  Kindest regards Jim 
K9AXN



----- Original Message ----- 
From: "Carl" <km1h at jeremy.mv.com>
To: "Jim Liles" <james.liles at comcast.net>; <hallicrafters at mailman.qth.net>
Sent: Thursday, January 29, 2009 1:12 PM
Subject: Re: [Hallicrafters] SR-2000 post production change


> Any high power amp will crystalize standard Tin-Lead solder over time; 
> Hallicrafters is not unique. Solder has a finite amount of resistance to 
> RF.  The simple cure is to remove all of the solder and flow in new and 
> dont worry for another 10-20 years. Or use real silver solder.
>
> Carl
> KM1H