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                           AeroElectric-List Digest Archive
                                      ---
                     Total Messages Posted Fri 06/24/16: 3
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Today's Message Index:
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     1. 05:10 AM - Re: OT: PCB coating removal  (rampil)
     2. 08:29 AM - Re: Re: OT: PCB coating removal  (rayj)
     3. 05:30 PM - Re: Re: OT: PCB coating removal  (Robert L. Nuckolls, III)
 
 
 
________________________________  Message 1  _____________________________________


Time: 05:10:02 AM PST US
Subject: AeroElectric-List: Re: OT: PCB coating removal
From: "rampil" <ira.rampil@gmail.com>


I don't recall a crystal in my old 1013A, but be that as it may, it seems odd
that someone would use an xtal to generate audio tones unless they needed
extraordinary frequency precision (an a lot of divider steps).

You might try a bit of MEK on a corner of the board. it should not hurt the components,
but might remove the PCB and component printing. The old 
potting compounds were pretty resistant to attack.

--------
Ira N224XS


Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=457398#457398


________________________________  Message 2  _____________________________________


Time: 08:29:37 AM PST US
Subject: Re: AeroElectric-List: Re: OT: PCB coating removal
From: rayj <raymondj@frontiernet.net>


Thanks Ira,

I'll give mek a try. The board is from an old telephone lineman's test 
hand set so it's generating 12 tones for dialing.

Raymond Julian
Kettle River, MN

The things we admire in men, kindness and generosity, openness, honesty, 
understanding and feeling are the concomitants of failure in our system. 
And those traits we detest, sharpness, greed, acquisitiveness, meanness, 
egotism and self-interest are the traits of success. And while men 
admire the quality of the first they love the produce of the second. 
-John Steinbeck, novelist, Nobel laureate (1902-1968)

On 06/24/2016 07:08 AM, rampil wrote:
>
> I don't recall a crystal in my old 1013A, but be that as it may, it seems odd
> that someone would use an xtal to generate audio tones unless they needed
> extraordinary frequency precision (an a lot of divider steps).
>
> You might try a bit of MEK on a corner of the board. it should not hurt the components,
but might remove the PCB and component printing. The old
> potting compounds were pretty resistant to attack.
>
> --------
> Ira N224XS
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=457398#457398
>
>


________________________________  Message 3  _____________________________________


Time: 05:30:04 PM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Re: OT: PCB coating removal

At 10:27 AM 6/24/2016, you wrote:
>
>Thanks Ira,
>
>I'll give mek a try. The board is from an old telephone lineman's 
>test hand set so it's generating 12 tones for dialing.

   Brings back memories . . . the DTMF tone encoders
   of bygone times were indeed crystal controlled.
   Here is an exemplar component.

http://tinyurl.com/hzxdjgw

   Very popular devices in the ham radio repeater
   communities 40 or so years ago.


   Bob . . . 

 

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