[TenTec] 238B Tuner problems

Bwana Bob wb2vuf at verizon.net
Thu Jul 15 11:56:46 PDT 2010


How  about using an NE-2 neon bulb as an RF sniffer?


				73,

				Bob WB2VUF

				

Bill Miner wrote:
> Natan and All,
> 
> The small wheel on the roller inductor comes from Ten-Tec with some black 
> conductive lubricant.  If you do not replace the lubricant after cleaning 
> you may experience problems from wear later on.
> 
> F Y I  even though I have been licensed just as long and love boat anchor 
> equipment I do NOT use a pencil to check for RF and have not done so since I 
> last had on old ARC-5 transmitter on the air.  Safety First!
> 
> 73,  Bill
> ----- Original Message ----- 
> From: "Natan Huffman" <W6XR at Frontiernet.net>
> To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
> Sent: Wednesday, July 14, 2010 4:38 PM
> Subject: [TenTec] 238B Tuner problems
> 
> 
>> Dear Friends,
>>
>> Today, I resolved a problem encountered with my Ten Tec 238B antenna 
>> tuner.
>> A week ago, my 238 started to misbehave and presented with what appeared 
>> as
>> an "open" in the tuner.  No discernable flash over had taken place as the
>> problem appeared spontaneously without any noise, smell or any indication
>> trouble was brewing.  The VSWR meter stopped working and no RF was getting
>> through to my Array Solutions Power Master residing after the tuner in the
>> RF chain.
>>
>> This morning a telephone call to John at mother Ten Tec ended up with
>> instructions to send it home to be subjected to proper trouble shooting,
>> however, to do that would involve being off the air for longer than what I
>> wanted to be.  Therefore one last attempt to ascertain the problem and at
>> Ten Tec Johns suggestion, I inspected all the wafers on the switches 
>> inside.
>> All the tabs were there and none showed wear at all.  Finally, I became
>> suspicious of just where the RF was going because using my #2 lead pencil 
>> I
>> could see it certainly was not getting to the output SO239 as it should. 
>> It
>> was easy to draw a spark up to the roller at the variable inductor but no
>> spark at all anywhere on the body of the inductor.  The wire wrapping 
>> around
>> the inductor body was void of any corrosion or flash indication.
>>
>> Having nothing to loose, I grabbed the can of contact cleaner and doused
>> both the wheel and all the wire on the inductor form.  While still damp, a
>> cotton cloth was used to wipe off the excess contact cleaner.  My 
>> suspicion
>> was confirmed as after the cleaning of the inductor and its little wheel,
>> all was well.  It became easy to get a 100 watt spark with the lead pencil
>> on the body of the inductor, the VSWR meter started working and the Power
>> Master showed RF just the way it should.  A few hours post, the 238 is 
>> doing
>> everything it used to do prior to becoming symptomatic.
>>
>> I suppose the moral here is to clean the inductor and its little wheel
>> because even if it looks clean, enough crud does form to insulate the 
>> wheel
>> from the wire on the form.  Perhaps others have found this same problem
>> before.  It's very nice to avoid a trip to mother Ten Tec and its 
>> associated
>> cost and inconvenience.  Using a wooden lead pencil for RF sniffing is 
>> only
>> allowed if you are into boat anchors and have been licensed over 40 years.
>> A mechanical pencil's use can be downright dangerous so only use a wooden
>> #2!
>>
>> 73
>>
>> Natan W6XR
>> Freeville, NY
>>
>>
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>> TenTec at contesting.com
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> 
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