[Hallicrafters] Need Help With SX-101 USB Problem

[Lee]

I had a problem like this when I bought a brand new SX-96 back in the 
late 50s.  The problem bugged me for a couple years.  I could always 
temporarily fix it by banging on the cabines.  Mind you, it came from 
the factory this way.  One day I was poking underneath and low and 
behold there was a tubular ceramic cap just slightly touching the main 
tuning frame.  By banging on the cabinet it just slightly removed the 
short for awhile.  You might have this condition with a part under the 
chassis.  When I moved the cap slightly,  I never had the problem again.

Lee, w0vt-

On 7/15/2015 6:33 PM, Mark K3MSB wrote:
> Hi Richard
>
> I have an SX-101A and have exactly the same problem you're experiencing.
>
> I've had my receiver for about 15 years and it started to do this about 5
> years ago.  I swapped the USB crystal with the one in my SX-111 and the
> problem went away.
>
> It came back last winter.    USB works fine when the radio is turned on,
> but cuts out after a while.   Switching between USB and LSB sometimes
> helps;  mostly not.
>
> I recapped my receiver several years ago and also did the cleaning with
> DeOxit.    Obviously, that didn't help.
>
> I think the only way to fix the problem is with an alignment as K9AXN
> mentioned.   Parts go out of tolerance after 50 years, and I'm not
> surprised part of the converter needs tweaked.     I suspect heating of a
> component and the resultant change in value is what is happening.   What
> you could do it try some freeze spray, but the offending part may be in the
> converter subchassis which would make it rather difficult to get to.
>
> I don't know if you need an entire alignment or not;  it's been many moons
> since I cracked the manual.
>
> 73 Mark K3MSB
>
>
>
> On Wed, Jul 15, 2015 at 5:07 PM, richard <ramnaz at peoplepc.com> wrote:
>
>> Hello.
>> Have a SX-101 that  when I go from USB to LSB & then want to go back to
>> USB it is Dead but if I pull the 12AT7 tube out & put it back in then the
>> receive in USB comes back on or if I turn the on & off many times then the
>> USB receive comes back on yet the LSB never goes out.. Any body have this
>> problem & if you fixed it can you tell me how? I have even put a small fan
>> inside & that does nothing .
>> Thanks Much
>>   Richard
>>
>> Richard Morris
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