[Hallicrafters] My First Boat Anchor Restoration: SX101 MkIII

[Pagel, Mike]

Jason, here are two web sites with training/tutorial resources that might be useful for obtaining a broad overview of the theory and practice of boatanchor troubleshooting and repair.

NRI Radio Repair Course:
http://www.fyrbotlz.com/Downloads.html  

"Elements of Radio Servicing" and a collection of other interesting articles and publications:
http://www.fyrbotlz.com/Downloads.html  

73, de Mike, K9UW
Amherst, WI


-----Original Message-----
From: hallicrafters-bounces at mailman.qth.net [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Jason Hissong
Sent: Tuesday, November 15, 2011 7:33 AM
To: Mike Everette
Cc: hallicrafters at mailman.qth.net
Subject: Re: [Hallicrafters] My First Boat Anchor Restoration: SX101 MkIII

Mike,

I meant 12AU7A.  My brain and my hands sometimes get out of synch (kinda like my brain and my mouth.. heheheh)

I have worked around high voltage with house wiring (service upgrades, running circuits, etc).  With these old radios, I just need to know what parts are the ones that get you.  And the proper way to short out a capacitor.  I am up to challenge.  I have a few boat anchor elmers I can speak with around here that can assist.

I want to get the proper test equipment to do this in the future.  I hear it can get addicting so I may as well build/buy the right stuff.

Thanks for your suggestions!

Jason N8XE

On 11/15/2011 7:36 AM, Mike Everette wrote:
> Jason,
>
> Did you actually mean to type "23AU7A" or was it 12AU7A?  If you actually have a 23AU7A in the V13 socket, it's being fed only about half heater voltage.  12= 12 volt filament; 23=23 volts (some weird series string TV tube??).
>
> Better get used to working on high voltage.  If you are scared of it, you really don't have much business sticking your hands in there.... Learn how to do it safely.
>
> Isolate your signal source from the high voltage, using a capacitor.  A 0.01 uF cap usually works well.  Be sure it's rated for at theast the value of the B plus voltage.
>
> 73
>
> Mike
> W4DSE
>
>
> --- On Tue, 11/15/11, Jason Hissong<jhissong at gmail.com>  wrote:
>
>> From: Jason Hissong<jhissong at gmail.com>
>> Subject: Re: [Hallicrafters] My First Boat Anchor Restoration: SX101 
>> MkIII
>> To: hallicrafters at mailman.qth.net
>> Date: Tuesday, November 15, 2011, 12:41 AM Quick update on my SX101 
>> Mk *2* :)
>>
>> I worked with a local ham over the radio and he assisted me in 
>> troubleshooting the radio.  This is what I know:
>>
>> I plugged a pair of headphones in and tested the audio stage.  I 
>> plugged a phono cord into the back, switched the rig to "phono" and 
>> touched the tip of the phono plug to cause a hum.  I heard the hum 
>> and the volume control works.  However, when I turn the calibrator 
>> on, and put the rig to USB or LSB, and tune around, I don't hear the 
>> calibrator at all.  I did not have an antenna plugged in.
>>
>> I tested the 1st Conversion Oscillator (V13, 23AU7A) by setting my 
>> TS450 to 7100kc + 1650kc = 8750kc, made a make-shift "antenna"
>> with a test
>> lead wrapped it around V3.  I turned the VFO knob up and down the 
>> dial and I heard the signal.  I tried this on 80, 20, and
>> 15 and heard it
>> there too (changing the TS450 frequency to the appropriate 
>> frequency).
>> I did not hear one on 10M (I did not try it with 160M).
>>
>> I also tried testing the 2nd conversion oscillator (V12,
>> 12AT7) by
>> setting my Kenwood to 1600kc, set it to LSB, and wrapped the lead 
>> around V12.  I did not hear anything.  I tried it with 1700kc and set 
>> the SX101 to USB.  Nothing.  I also tried it reversed in case I 
>> messed it up.
>>
>> So this is where I am now.  The ham who was helping me suggested I 
>> need to inject a signal to the grid of each stage of the radio and 
>> hear which one does not work, starting from the audio stage all the 
>> way to the antenna.  I don't have a signal injector to do this.
>>
>> The other thing is, I am used to working on low voltage stuff.  I 
>> don't want to be putting this signal injector onto the wrong thing 
>> and *poof*!!!
>>
>> 73, Jason N8XE (new boatachorologist) 
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