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I own it...What is it??

Started by Doug Rose, December 23, 2014, 06:21:34 PM

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Doug Rose

I found this cleaning out the phone phone.  Metal approx 9"tall, by 6 by 6. Black Glass with a Bulldog MP. Looks like it had a watch case receiver that is not present. Pristine inside, need a paint job, just surface oxidation, no pitted or deep rusting. I'm going to part it out the Bulldog and chuck the rest unless you know what it is!

What is it???...Doug
Kidphone

unbeldi

#1
Looks professionally made.
The circuit diagram should tell the story, but is too blurry to decipher in the picture.
The induction coil is either a 3-winding transformer, or what I suspect perhaps has only two windings with center taps on each. On the secondary side one-half of the coil would be used for the transmitter, the other for the receiver.
The coil looks pretty robust, beefy, as if designed for higher than normal voltages.
If not given on the diagram, I would measure the DC resistances of the coils, which should tell more of the purpose.
I suspect it is an announcement station, of something like a rail way station, with a pushbutton to connect the transmitter, similar to the likes of the WECo 501A subset.  AFAIK, these kind of things were still used into the 60s and 70s, perhaps even later, and often made by specialty companies.
Why part it out? Seems pretty complete aside from the receiver.

AE_Collector

I first noticed the little yellow plastic wire clip holding the wire harness as it comes onto the door/lid. AE used clips like that in some phones, possibly 880 Speakerphones. Then I noticed that the Induction coil is AE as well. Other than that.....I have no idea what it is.

Terry

unbeldi

Quote from: AE_Collector on December 23, 2014, 08:55:52 PM
I first noticed the little yellow plastic wire clip holding the wire harness as it comes onto the door/lid. AE used clips like that in some phones, possibly 880 Speakerphones. Then I noticed that the Induction coil is AE as well. Other than that.....I have no idea what it is.

Terry
Yes, I agree.  I suspected that coil to be AE, the part number appears so typical, but I haven't tried to match it to anything.

unbeldi

#4
The push button has a 1500 ohm resistor on its terminals and there is another on the terminal strip.
I have an AE railroad subset that also uses a 1500 Ω ohm resistor on the switch. The switch shorts the resistor normally to provide full audio reception, but when the transmitter is connected into the circuit when the button is pushed, it enables the resistor to cut down on the sidetone, which could be very distracting for a dispatcher at a public location.

PS: here is a circuit diagram of my set:

Kenton K

Unbeldi,

What program do you use to draw those schematics?

Ken

Phonesrfun

He uses Digi-Key

http://www.digikey.com/schemeit/

He told me about it a while back and I have used it too.  It's free.
-Bill G

unbeldi

That answers it.
It's quite easy to use, had some minor issues initially, well still some, but they keep improving it.

Doug Rose

#8
Here is a better shot of the schematics....Doug
Kidphone

poplar1

This one also has the 1500 Ohm resistor: WE 295-AK converted with AE parts.

http://www.ebay.com/itm/321625299613
"C'est pas une restauration, c'est une rénovation."--François Martin.

Doug Rose

David...any idea of its use? I will clean it up and find a watchcase for it...Doug
Kidphone

poplar1

I always assumed these were for railroads. Your diagram shows a foot switch, which may have been used by a dispatcher.
"C'est pas une restauration, c'est une rénovation."--François Martin.

unbeldi

#12
The diagram includes the circuit schematic in the top small portion and it turns out to be essentially identical in concept to mine, if you compare.

The induction coil is a three winding coil with one of them toward the line,  D.C.-isolated by the capacitor. The primary is on the transmitter and battery circuit and the another is for the receiver, as I explained before. Counting what as primary, secondary or tertiary is almost meaningless, but usually the transmitter coil is called the primary.

So, this is indeed an announcer station for a railroad or similar public address system.

unbeldi

#13
David's eBay picture shows another one of these, with the same electrical construction, and it is interesting to note that the diagram there also designates a WECo 1148D transmitter arm as the telephone instrument, as does mine.

Here is a picture of my subset.  Mine is much smaller. It is based on an AE No. 32 Extension Box. Very neat and almost cute.
This one has a closed-core induction coil already.

[update: the images are misidentified as AE38. The container box is actually an A.E. Type 32 Extension Box.]

unbeldi

Quote from: poplar1 on December 24, 2014, 05:51:02 PM
I always assumed these were for railroads. Your diagram shows a foot switch, which may have been used by a dispatcher.

These type of devices were available with either/or a push button or a foot switch.  The foot switch is shown is broken lines, and therefore optional.