[Milsurplus] Milsurplus Digest, Vol 112, Issue 5

Yahoo! Member Services mike.tara at att.net
Mon Aug 5 12:25:14 EDT 2013


how much are you asking for it



________________________________
From: "milsurplus-request at mailman.qth.net" <milsurplus-request at mailman.qth.net>
To: milsurplus at mailman.qth.net 
Sent: Saturday, August 3, 2013 6:38 PM
Subject: Milsurplus Digest, Vol 112, Issue 5


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Today's Topics:

  1. Re: Crosley REP with Bad Audio Output Tranny (John Hutchins)
  2. Re: Crosley REP with Bad Audio Output Tranny (Bruce Gentry)
  3. AN/GRR-5 (Richard C. Grosser)
  4. Need  transformer for BC-614 (Bill Fondren)
  5. 3A5 Filament Voltage Question (J. Forster)
  6. Re: 3A5 Filament Voltage Question (Al Klase)
  7. Re: 3A5 Filament Voltage Question (Bill Cromwell)


----------------------------------------------------------------------

Message: 1
Date: Sat, 03 Aug 2013 12:05:33 -0500
From: John Hutchins <jphutch60bj at gmail.com>
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] Crosley REP with Bad Audio Output Tranny
Message-ID: <51FD385D.2010107 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Dave -
IF the inside is tar - Then go to goodwill or thrift store and get a 
hotplate or electric skillet.
Get some ranch gloves or tongs heat up transformer and tar,  and pour it 
out.
Melting point of roof tar is 65.5 degrees Celsius, ~= 150 degrees F.
Hutch



On 8/3/2013 8:30 AM, David Stinson wrote:
> Thanks to everyone who helped with this.
> The output transformer is bad.  I do have an "open frame" replacement 
> that works well and will fit inside the original
> rectangular transformer case.  However, the original is potted.
>
> I could remove the end pieces and melt the gloop out with
> a propane torch.  Anyone have experiance in doing it some other way?
>
> 73 DE Dave AB5S
>
> ______________________________________________________________
> Milsurplus mailing list
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>
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------------------------------

Message: 2
Date: Sat, 03 Aug 2013 14:05:04 -0400
From: Bruce Gentry <ka2ivy at verizon.net>
To: Milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] Crosley REP with Bad Audio Output Tranny
Message-ID: <51FD4650.3070809 at verizon.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

If you can get the end off or otherwise open the case a bit, immerse it 
in gasoline for a week or so. Use a covered and loosely sealed container 
so fume pressure can escape when it needs to, but otherwise trap the 
fumes. Set it in a warm place outside, agitate it avery day. The pitch 
will dissolve.  For a faster but risker way, get a cheap hot plate you 
don't mind losing, and use a double boiler to steep the transformer in 
very hot kerosene.  Use a variac to keep the water in the bottom pan 
just simmering, and of course, do it outdoors where  an accidental fire 
won't harm anything. The transformer core and windings will usually pour 
out of the case easily after a couple hours. I haven't had it catch fire 
yet, but it can and you must be prepared if it does.  Now for a bit of 
history:  Between the World Wars, critical massive machine tools were 
preserved by mounting them on worn out railroad flat cars, then spraying 
and dousing them with molten tar. They could then be stored outdoors 
with little chance of rusting. When WW2 broke out, the cars were pushed 
through tunnels where they were showered in steam heated kerosene to 
wash the tar off.  The preservation was excellent, and the tar saturated 
kerosene was then used to fire the boilers.

      Bruce Gentry, KA2IVY

On 8/3/13 9:30 AM, David Stinson wrote:
> Thanks to everyone who helped with this.
> The output transformer is bad.  I do have an "open frame" replacement 
> that works well and will fit inside the original
> rectangular transformer case.  However, the original is potted.
>
> I could remove the end pieces and melt the gloop out with
> a propane torch.  Anyone have experiance in doing it some other way?
>
> 73 DE Dave AB5S
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net/
> Please help support this email list: http://www.qsl.net/donate.html
>


------------------------------

Message: 3
Date: Sat, 3 Aug 2013 12:07:49 -0700
From: "Richard C. Grosser" <richard at palmspringsairmuseum.org>
To: <Milsurplus at mailman.qth.net>
Subject: [Milsurplus] AN/GRR-5
Message-ID: <[email protected]>
Content-Type: text/plain;    charset="us-ascii"

I have a very good working AN/GRR-5 receiver (R-174/URR receiver, model
PP-308/URR power supply, cabinet CY-615/URR. The only modification is the
replacement of the selenium rectifier unit with diodes. I have also built a
plug-in adapter with a standard pj-55 phone jack for it.  I would like to
dispose of this unit either by selling it or trading it for a working
solid-state, general coverage receiver capable of receiving AM, CW and SSB.
Preferably one with VLF coverage. Is anyone interested in purchase or trade.
I will make photos available upon request.

Richard 




------------------------------

Message: 4
Date: Sat, 3 Aug 2013 12:37:12 -0700 (PDT)
From: Bill Fondren <bill.fondren at sbcglobal.net>
To: "milsurplus at mailman.qth.net" <milsurplus at mailman.qth.net>
Subject: [Milsurplus] Need  transformer for BC-614
Message-ID:
    <1375558632.1837.YahooMailNeo at web184305.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Hi Guys??? I am in need of an audio output transformer for a BC-614.? email?? bill.fondren at sbcglobal.net? Thanks? K5PML

------------------------------

Message: 5
Date: Sat, 3 Aug 2013 17:18:55 -0700 (PDT)
From: "J. Forster" <jfor at quikus.com>
To: ARC5 at mailman.QTH.net, boatanchors at mailman.QTH.net,
    Milsurplus at mailman.QTH.net
Subject: [Milsurplus] 3A5 Filament Voltage Question
Message-ID:
    <7199.12.226.214.5.1375575535.squirrel at popaccts.quikus.com>
Content-Type: text/plain;charset=iso-8859-1

I'm playing with an ART-4 Transmitter. This unit is for reporting the
blast intensity near an airplaned towed target tube (sock), hence the
closeness of the shell to target can be estimated.

Anyway, after tracing the circuit, it has an oscillator and an amplifier
stage.

The filament on the 3A5 is parallel wired.

The spec sheet says 1.4 VDC, Max. A current alkaline battery will put out
significantly more than that.

I want to run the thing off an adjustable DC supply, and allow some margin.

Does anyone know roughly what the minimum DC filament voltage to apply for
enough emission to work reasonably well? I just want to test the operating
frequency and get a rough idea of the modulation deviation.

Thanks,

-John

===================



------------------------------

Message: 6
Date: Sat, 03 Aug 2013 21:20:39 -0400
From: Al Klase <ark at ar88.net>
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] 3A5 Filament Voltage Question
Message-ID: <51FDAC67.1060104 at ar88.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi John,

I fail to see that 1.4 is defined as the maximum filament voltage, 
rather 1.4 is the voltage at which the typical characteristics are measured.
See: RCA HB3 page here: 
http://www.mif.pg.gda.pl/homepages/frank/sheets/049/3/3A5.pdf

I've always assumed that 1.4 is the nominal filament voltage, and that 
1.5 or maybe even 1.6 is not a reliability problem.  I also assume that 
you should get reasonable performance down to about 1 volts, the so 
called "end point" where the battery has delivered 80+ percent of it's 
available energy.

Here's another situation where I'd really like to see the original RCA 
applications notes that must have existed in one form or another. when 
these tubes were introduced to the market.

Regards,
Al


On 8/3/2013 8:18 PM, J. Forster wrote:
> I'm playing with an ART-4 Transmitter. This unit is for reporting the
> blast intensity near an airplaned towed target tube (sock), hence the
> closeness of the shell to target can be estimated.
>
> Anyway, after tracing the circuit, it has an oscillator and an amplifier
> stage.
>
> The filament on the 3A5 is parallel wired.
>
> The spec sheet says 1.4 VDC, Max. A current alkaline battery will put out
> significantly more than that.
>
> I want to run the thing off an adjustable DC supply, and allow some margin.
>
> Does anyone know roughly what the minimum DC filament voltage to apply for
> enough emission to work reasonably well? I just want to test the operating
> frequency and get a rough idea of the modulation deviation.
>
> Thanks,
>
> -John
>
> ===================
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net/
> Please help support this email list: http://www.qsl.net/donate.html

-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/



------------------------------

Message: 7
Date: Sat, 03 Aug 2013 21:38:25 -0400
From: Bill Cromwell <wrcromwell at gmail.com>
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] 3A5 Filament Voltage Question
Message-ID: <51FDB091.3090709 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 08/03/2013 09:20 PM, Al Klase wrote:
> Hi John,
>
> I fail to see that 1.4 is defined as the maximum filament voltage, 
> rather 1.4 is the voltage at which the typical characteristics are 
> measured.
> See: RCA HB3 page here: 
> http://www.mif.pg.gda.pl/homepages/frank/sheets/049/3/3A5.pdf
>
> I've always assumed that 1.4 is the nominal filament voltage, and that 
> 1.5 or maybe even 1.6 is not a reliability problem.  I also assume 
> that you should get reasonable performance down to about 1 volts, the 
> so called "end point" where the battery has delivered 80+ percent of 
> it's available energy.
>
> Here's another situation where I'd really like to see the original RCA 
> applications notes that must have existed in one form or another. when 
> these tubes were introduced to the market.
>
> Regards,
> Al

Hi,

I'm a heathen and have been running my battery tubes on alkaline 
flashlight cells. So far no problems. I haven't bothered to measure the 
no-load terminal voltage of the 'dead' cells - sorry. If I remember to 
turn the gear off those cells last a long, long time. All of that is 
pretty much subjective but I can testify that 1.5621300671 volts will 
apparently not harm the tubes but maybe 1.5621300672 volts would make 
them explode.

I'm putting together a TX/RX set with them for portable use and I'll 
make it a point get more detailed data because I will need to know how 
many battrys to take on field trips.

73,

Bill  KU8H


------------------------------

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