[Hammarlund] Unstable Oscillator adjustments in the HQ-180

[Al Parker]

Hi guys,
    According to my schematic the osc. coils in the HQ-180 have external 
caps, the IF's have internal, and I've had problems with them a few times.
    It does sound like that sort of problem, a mechanical one, but it 
appears that it happens on all bands.  Maybe ck for bad solder connections 
at the coils or bandswitch?
73,
Al, W8UT

----- Original Message ----- 
From: <w5jo at brightok.net>
To: "K3PID" <Ron.K3PID at sbcglobal.net>; <hammarlund at mailman.qth.net>; 
<manualman at juno.com>
Sent: Monday, February 01, 2016 4:56 PM
Subject: Re: [Hammarlund] Unstable Oscillator adjustments in the HQ-180


> What is the condition of the bandswitch contacts.  Had a similar problem 
> with a National and cleaning them with denatured alcohol  fixed my 
> problem. Other than that, I am beginning to think the mica capacitors 
> located in the bottom of the cans are the problem which will require 
> removal and replacement.  Usually the capacitor problem will be one or two 
> of the cans not all of them, so what, beside the bandswitch, is common to 
> the oscillator section.  I believe someone mentioned the oscillator tube.
>
> 73,
>
> Jim
> W5JO
>
> -----Original Message----- 
>
> OK, as far as I can determine the slugs and caps are in good shape. The
> touchy issue means that when I put the adjusting tool on the screw and 
> just
> tweek it a little the output jumps.  On all of the IF transformers, I can
> turn the adjustment slowly and see the output drop or increase relatively
> slowly so that I can sweep through the peak and back up to find it then
> remove the tool and have it stay put.  with the oscillator transformers 
> even
> a slight turn causes a sharp change in output and it is almost impossible 
> to
> stop on a peak. Sometimes just removing the tool shifts the output peak...
> The "problem" exist on all of the HF Osc transformers so it is something
> common to all band switch positions. All the tube socket voltages and
> resistances are nominal ( ±10% maybe ). I have the set working fairly well
> but can't help but think that it could be better...  I've been using it 
> for
> the Classic Exchange so after Tuesday I will put it back on the bench and
> continue trouble shooting.... I was hoping someone had experienced the
> symptom before and could report their findings...
>
> TNX  es 73
> Ron K3PID
>
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