[Hallicrafters] More SX99 questions

Thu Feb 5 22:30:30 EST 2009

Hi All,

FYI: The HHI (Halligan's Hallicrafters International) web site offers you 
'live' tech support via e-mail! From the home page locate the 'technical 
assistance' link and go for it!

The answers to your Hallicrafters technical questions will be sent direct to 
you! They will not appear on the HHI web site or on any of the 'qth.net' 
lists! If you should desire to post your Q/A, please feel free to do so. 
However, be sure to include the name, call sign and source of said 
information when you post it elsewhere!

Thanks and good color code crunching!

www.w9wze.net

----- Original Message ----- 
From: "N8IE" <n8ie at woh.rr.com>
To: "'Mark Drakage'" <markdd at nc.rr.com>
Cc: "'ANTHONY CASORSO'" <canthony15 at msn.com>; 
<hallicrafters at mailman.qth.net>; "'rbethman'" <rbethman at comcast.net>
Sent: Thursday, February 05, 2009 10:16 PM
Subject: Re: [Hallicrafters] More SX99 questions

> Hello Mark,
> You are right, I re-read it and understand it now.
> Thanks for bearing with me. I still have  little more work to do but I 
> think
> I have a handle on the gimmick concept now.
>
> 73
> Dan, N8IE
>
> -----Original Message-----
> From: hallicrafters-bounces at mailman.qth.net
> [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Mark Drakage
> Sent: Thursday, February 05, 2009 10:00 PM
> To: n8ie at woh.rr.com
> Cc: 'ANTHONY CASORSO'; 'rbethman'; hallicrafters at mailman.qth.net
> Subject: Re: [Hallicrafters] More SX99 questions
>
> Hi Dan, I assumed that from what was described in earlier email was that 
> one
> end of the gimmick wire was was already soldered to pin 3 of V5 which is 
> the
> BFO output. If that is the case, then the other (insulated) end would wrap
> at least one turn around the wire connecting transformer
> T2 to pin 4 of V4, or if it's already very close to pin 4 of V4, it could 
> be
> wrapped around the tube socket pin 4. You do not  want the gimmick wire
> soldered on both ends. Basically you want a wired connection of the BFO
> output (pin 3 of V5) to run over to the connection of T2 pin1 and pin 4 V5
> and have an insulated wrap 1 to 2 turns. That's where the BFO signal is
> capacitively coupled to the control grid of V4 where it mixes with the
> output of the 1st IF amp via the (gimmick) capacitor.
>
>
> n8ie at woh.rr.com wrote:
>> Hello Mark,
>> So the gimmick wire should be soldered to pin 3 of V5?
>>
>> Thanks for the info, that is going into my SX-99 folder. :-)
>>
>> 73
>> Dan, N8IE
>>
>> ---- Mark Drakage <markdd at nc.rr.com> wrote:
>>
>>> Hi, there should be a wire coming from pin 1 on T2 to pin 4 of V4.
>>> The gimmick wire coming from pin 3 of V5 is typically wrapped around
>>> the T2 pin 1/ pin V4 wire at least one turn. Of course the gimmick
>>> wire needs to be insulated where it wraps around the other wire. Each
>>> turn produces about 1-2 pf capacitance. One turn should work fine.
>>> Doing this would also keep it from moving around from vibration. My
>>> S-40B and S-108 have the exact same circuitry for injecting a local
>>> oscillator carrier to mix w/ the IF signal coming out of the 1st If amp
> stage via T2.
>>>
>>> For anyone that owns an S-38 (not applicable on the a,b,c,d or e
>>> version), or a National NC-188, their gimmick wire wraps around the
>>> wire that connects the 2nd IF amp output transformer to the plate of
>>> the detector tube. This works OK if all you want to do is listen to
>>> CW but produces poor results for listening to SSB. Just unwrap the
>>> gimmick wire and move it to the same equivalent wire that feeds IF
>>> from the 1st IF stage output transformer to the control grid pin of
>>> the 2nd IF stage. In other words just like it's done on the S-99, S40
>>> and S-108. This makes a vast improvement in audio quality when
>>> listening to SSB on S-38's and NC-188's. Reason is none of these
>>> receivers have a true product detector stage, but the pentode tube
>>> used in the IF stage acts as a much better virtual product detector
>>> for mixing the IF and LO than a diode detector tube does.
>>>
>>> regards,
>>>    Mark
>>>    KJ4FJK
>>>
>>>
>>> N8IE wrote:
>>>
>>>> THANKS!
>>>> I un-wired mine and let it loose near the pin and it works fine.
>>>> I guess I need to secure it so it does not move when bumping the
>>>> radio around or moving it.
>>>>
>>>> You guys a great, thank you all!
>>>>
>>>> 73
>>>> Dan, N8IE
>>>>
>>>> -----Original Message-----
>>>> From: hallicrafters-bounces at mailman.qth.net
>>>> [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of rbethman
>>>> Sent: Tuesday, February 03, 2009 4:11 PM
>>>> To: hallicrafters at mailman.qth.net
>>>> Cc: ANTHONY CASORSO; n8ie at woh.rr.com
>>>> Subject: Re: [Hallicrafters] More SX99 questions
>>>>
>>>> Dan,
>>>>
>>>> The end that you found loose?  Do NOT solder it!  It is indeed the
>>>> "gimmick"!
>>>>
>>>> The insulated wire is simple left extended outside the shielding.  I
>>>> just pullked mine out of its cabinet.
>>>>
>>>> Bob - N0DGN
>>>>
>>>> n8ie at woh.rr.com wrote:
>>>>
>>>>
>>>>> Thanks Bob,
>>>>> Can anyone confirm this easily?
>>>>>
>>>>> When the problem first happened, switching the AM\CW switch made no
>>>>>
>>>>>
>>>> difference and only a local broadcast station could be heard with
>>>> the volume cranked. I found the wire loose and soldered it back to
>>>> V5. This fixed the problem except now when the AVC is on, I get a
>>>> loud squeal, but the sensitivity works fine otherwise. Sounds like
>>>> it just slipped far enough away from the tube to loose coupling.
>>>>
>>>>
>>>>> I appreciate all the help guys!
>>>>>
>>>>> 73
>>>>> Dan, N8IE
>>>>>
>>>>> ---- rbethman <rbethman at comcast.net> wrote:
>>>>>
>>>>>
>>>>>
>>>>>> Yep, that is "another" method of creating a gimmick.
>>>>>>
>>>>>> If I'd dig out my SX-99 and look, I could confirm it.  It is sort
>>>>>> of buried right now.
>>>>>>
>>>>>> Another project with too little time.
>>>>>>
>>>>>> Bob - N0DGN
>>>>>>
>>>>>> ANTHONY CASORSO wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> I the Halli sets I am familiar with, the gimmick is just a piece
>>>>>>> of standard hookup wire stripped on one end only. The stripped
>>>>>>> end is soldered per usual but the other end is just wrapped
>>>>>>> around a tube socket pin to provide a few pf of coupling. It
>>>>>>> should not be connected directly.
>>>>>>>
>>>>>>> Tony
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> Date: Tue, 3 Feb 2009 14:10:22 -0500
>>>>>>>> From: rbethman at comcast.net
>>>>>>>> To: hallicrafters at mailman.qth.net
>>>>>>>> CC: n8ie at woh.rr.com
>>>>>>>> Subject: Re: [Hallicrafters] More SX99 questions
>>>>>>>>
>>>>>>>> Dan,
>>>>>>>>
>>>>>>>> A "gimmick" is a low value capacitor that is made by twisting
>>>>>>>> what is usually enameled wire a "few" turns. They were normally
>>>>>>>> a low voltage component.
>>>>>>>>
>>>>>>>> Bob - N0DGN
>>>>>>>>
>>>>>>>> n8ie at woh.rr.com wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> While working on getting the SX99 back up and running I have
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>> another question.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>> One of the main faults was the wire running from pin 3 of V5 to
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>> pin4 of V4 came off. It did not look like it was originally on
>>>>>>> very well to begin with.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>> This wire is shielded and in the schematic is listed in part as
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>> C38 Gimmick 2uF.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>> Exactly what is a "gimmick" capacitor?
>>>>>>>>>
>>>>>>>>> Thanks es 73
>>>>>>>>> Dan, N8IE
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>> --
>>>>>> Bob - NØDGN
>>>>>>
>>>>>> ______________________________________________________________
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>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>> --
>>>> Bob - NØDGN
>>>>
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>>
>>
>>
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