I need help -- old wooden phone will not disconnect

[wheelhorse12]

I am in need of some technical assistance.  I am hoping that someone from the forum can provide some guidance.  Please let me start by apologizing for my ignorance of the technical workings of a telephone. 

The issue – I recently purchased an old wooden crank telephone.  I was hoping that I could use this phone to receive calls.  The phone appears to be in remarkable original condition.  I don't know for sure who the manufacture is, but the handset is marked Western Electric.  Inside the phone contains a 3-bar magneto and all of its original components including a wiring schematic.  I have attached some images for reference.

I connected my phone lines (L1 – green & L2 – red) to the phone and was able to get a dial tone immediately.  With the handset down and turning the crank the bells ring and I am able to make an outside call (although it is random who I get).  The problem is I am unable to receive calls.  The phone appears to never disconnect the line.  The only way to disconnect the line is to unplug the phone.  I really don't know what to do.

I have researched throughout the web and came across an excellent article about converting local battery to common.  My other ignorant question is do all magneto phones use a local battery?  Looking at my wiring diagram, there is no indication of a battery.  I'm confused. 

I need your help, I'm really lost.

Thanks in advance
Kevin

[G-Man]

I suspect this set was a product by Telephone Repair and Supply/Dan Mac.

First, disconnect one of the bell wires. Since there is not a condenser in series with it the line is seized by the windings. At some point you will need to add one but for now see if you still receive dial-tone and can talk-out on it. If not, the try strapping the battery terminals together and seeing if it remedies the problem.

This is not the correct way but if it works! Let us know the results and if needed we can provide further assistance.

[AE_Collector]

The short answer is that Magneto phones are not compatible with today's common battery phone systems. Lots of modifications will be needed to make it work somewhat properly on a present day phone line. Lots of reading here on the Classic Rotary Forum will get you there though!

Terry

[Phonesrfun]

Terry is right.  That phone will not work on a modern phone line.  Particularly, you do NOT ever want to crank the phone while it is connected to the line.  You could damage the phone company equipment, because ringing current is approx 75 or 80 volts, and modern lines are not set up to have the subscribers sending ringing current back to the central office. If you are reasonably good at soldering and building an electronic project, there is a project on this forum that I co-wrote that you can build that will allow you to connect your phone to the line successfully.  You will, however, still not be able to send ringing voltage back up the phone line.

Another member of this forum, (Stub), built the circuit and it works quite well for him.

I can do a search and find the project if you would like.

[Phonesrfun]

Here is the link to a link



http://www.classicrotaryphones.com/forum/index.php?topic=5616.msg68091#msg68091

[G-Man]

Typically, no it would not work without the hack you are proposing. However, since it has a non-standard induction coil that appears to have options for local battery and perhaps common battery service*, thought we might want to take it one step at a time in attempting to guide him through the process of getting his phone to operate correctly without major modifications.

The first step is to disconnect the bells to see if that would stop the line from being seized while the handset  is on-hook. Next is a simple test to see if dial tone is rendered when the handset is off-hook.

My eyesight is rather poor so I find it difficult to clearly read the schematic but it appears that possibly the transmitter may work if the battery terminals are strapped together.  We can then take other steps. If he needs to cut-into the wiring harness to implement the hack then fine! But let it be the last resort instead of the first step.

Since Telephone Repair and Supply/Dan Mac were legendary in their building services, it would be a shame to destroy their legacy if it turned-out to be unnecessary.

*Stromberg Carlson, Leich and others built instruments with these types of induction coils so their phones could be wired for either L.B. or C.B. service.

[dsk]

We will never agree about how to solve this.  
My suggestion is to:
  put a strap between L1 and L1
  connect the line between the 2 battery terminals.
  disconnect the white lead betwin inductor and ringer, and put in a 1µF 200V capacitor betwin the ringer and the left battery terminal.
  A resistor of 200 -330 ohms betwin handset terminals 2 and 3 may reduce some noise.


Good luck.

dsk

Almost forgot the last point; tell us how it turns out.

[HowardPgh]

Wheelhorse
The battery connections are shown on the upper right of your diagram.
Rather than alter such a good looking phone, get another magneto type phone and make an intercom system!!

[Dennis Markham]

(DSK, I had to delete your post as it was causing some type of problem where only a blank page would appear.  I believe it had to do with the schematic drawing you uploaded.  Apparently you had some trouble uploading it.  I don't know if it was the size or perhaps the file extension.  If you can, reduce the size and try it again?)

~Dennis

[dsk]

Had some problems uploading this picture.

In a period the telco modified old magnetos with dials.
They even used it with local battery for the transmitter.

It is a lot arguments against doing this, But in the twenties they did.

So the simplest way to use your phone is to just put it up, put a capacitor in series with the ringer, find some batteries, and go on. A dial may even be put on the line without any further changes on the phone itselves.
Unscrew the handle on the generator, and just store it in the phone will prevent sending ringing current out on the telephone line.

dsk