[Hallicrafters] SX-96 Oscillator Pulling on 10 meters

[Mike Everette]

Another tube you need to check and maybe sub is the VR-150.

Have you (I assumed you did) checked values of resistors?  I rather suspect you have several which may have drifted.  Look at those associated with the VR-150; also the screen resistors in the RF, mixer and 1650 IF stages.  Yeah, I know, that little box with the high IF is a B**** to get into; but it's gotta be done.

You might also try a new 5Y3 rectalfire.  They do get weak; and when this happens it can and does cause many kinds of strange problems that you might think came from elsewhere.

The SX-96 is an SX-100 sans the notch filter (moderately useful), antenna trimmer (rather nice) and crystal calibrator (THE MOST useful addition made with the SX-100).

The biggest issue I recall with the SX-96 (which I used as a nain receiver for years) is microphonics, especially on 15 and 10 meters.  If someone knocked on the front door at my house, it could be heard in the speaker.  The next biggest was that if my foot hit the table, the receiver was likely to lose the frequency of the signal.  

You learned breath control when using one.  That skill comes in handy if you're a swimmer, or a singer.

73

Mike
W4DSE


--- On Fri, 11/18/11, ka9p <ka9p at aol.com> wrote:

> From: ka9p <ka9p at aol.com>
> Subject: [Hallicrafters] SX-96 Oscillator Pulling on 10 meters
> To: hallicrafters at mailman.qth.net
> Date: Friday, November 18, 2011, 11:40 PM
> Even though it seems not to be on
> anybody's list of great receivers this week, can anyone
> offer a clue about what I should check first on an SX-96
> that  pulls the oscillator on 10 meters when the AVC is
> kicking in?  The sunspots are conspiring to identify all
> the weaknesses of the old stuff that seemed to be working
> well for the last few years.
> 
> I remember seeing this more than once over the years on 96s
> and 100s but darned if I can remember the cause or the cure.
>  I did swap out the oscillator tube hoping for an easy fix
> but 2 like for like swaps didn't fix the problem.
>  
> Thanks alot, Scott
> 
> 
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