[Hallicrafters] SX-111 Calibration?

[Bob Macklin]

I got inside where I can see what I've go.

The "Dial Reset" is a small trimmer connected directly to the LO. The 
schematic is in 4 sheets so it is hard to read.

I have 80, 40, and 20 adjusted. The coils are very sensitive.

Right at the moment the only contact cleaner I have is from MG Chemicals. 
I'll have to order some DeOxit.

I'm going to try the signal generator later today. If the sensitivity looks 
OK I am not going to touch anything for now.

This receiver was a surprise to me. I'm used to lower end Hallictafter's 
receivers. I also have a SX-110. This is much more of a receiver. It's a 
subset of the SX-100. One less 50KHz IF stage.

I've been used to the audio output stage on the other Hallicrafter's GC 
receivers. This one is a simple 6AQ5 output stage which is just fine for 
this receivers purpose.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message ----- 
From: "Richard Knoppow" <1oldlens1 at ix.netcom.com>
To: "Bob Macklin" <macklinbob at msn.com>; "Halicrafters" 
<Hallicrafters at mailman.qth.net>
Sent: Friday, July 13, 2012 3:14 PM
Subject: Re: [Hallicrafters] SX-111 Calibration?


>
> ----- Original Message ----- 
> From: "Bob Macklin" <macklinbob at msn.com>
> To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>; "Halicrafters" 
> <Hallicrafters at mailman.qth.net>
> Sent: Friday, July 13, 2012 10:40 AM
> Subject: Re: [Hallicrafters] SX-111 Calibration?
>
>
>> Thanks,
>>
>> I am thinking of centering the Dial Reset then adjusting the LO to the 
>> proper end point.
>>
>> My initial tests showed the LO would start OK when the unit was turned 
>> on. But would quit when the band was changed.
>>
>> Working inside the LO section of this thing is extremely difficult for 
>> me.
>>
>> I'll know more later today.
>>
>> Bob Macklin
>> K5MYJ
>> Seattle, Wa.
>> "Real Radios Glow In The Dark"
>
>     I think you are doing exactly the right thing. I assume you have the 
> handbook.  There are two at BAMA one for the MkI, I don't know how much 
> difference there is.  I would do a complete RF alignment.  If you have the 
> necessary generator check the IF also but its much less likely to have 
> drifted off. The adjustments will allow you to set both high and low band 
> ends. Center the pointer before doing the alignment and, if its easy to 
> move, lock it with a bit of tape. Also, the alignment instuctions want you 
> to check what they call indexing, that is simply making sure that the 
> pointer is at the low end of all the scales with the tuning capacitor 
> closed all the way.  If its off it will throw off the other adjustments. 
> This is a mechanical adjustment and not likely to change. Once adjusted at 
> the frequencies specified the dials should be pretty accurate overall. 
> There may be minor errors in the center of the bands due to slight 
> non-linearity of the tuning capacitor but the calibrator should take care 
> of this.
>    The procedure will also insure the RF stages are all tracking for best 
> sensitivity.
>    About the intermittent oscillator, even though you cleaned the band 
> switch contacts they may still be intermittent.  I suggest cleaning them 
> using Deoxit D5 and when that has evaporated treat with Deoxit G5. 
> Although Caig says its for gold contacts in fact its a protective 
> treatment for _all_ contacts after they have been cleaned with D5. My 
> experience with D5 is that it will clean some contacts that will become 
> intermittent or noisy again after a day or so.  In the past I've used 
> General Cement Tuner-Lub to protect them after cleaning with Deoxit. That 
> has worked very well and you may also want to try that. Also, when you 
> clean the contacts work the switch back and forth many times with the 
> contact cleaner still wet. That will tend to polish off whatever is on the 
> contact.  Its still possible that there is something else wrong but give 
> this a try.  If you can get use of a good tube tester check the tubes. 
> Bad tubes are not as frequent as sometimes thought but a really weak one 
> will cause trouble.
>    This looks like a good little receiver and worth some effort to get 
> working right. Keep in touch and let me know how its coming.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com
>