WWI 1917 Field Telephone Ringer Problems

[dsk]

Thank you for the diagram.
This makes it possible to decide the termination.
Red is common, Yellow is transmitter, and Green is Receiver. This makes 2 wires on R (both transmitter, and receiver)
This old telephone has a hook switch, and when you go off hook you should transmit and listen all the time. To test short the line terminals, or connect another known working phone. be careful with battery voltage, if you don't know, use approx 3V. Magnets may have lost some magnetism, but it seems like using them helps.

One of the really interesting thing are this WW1 phone may be used together with a fully electronic field telephone sold today.

dsk

[dsk]

They are actually EE-3 field phones otherwise called 1917 Camp telephones (Models A or B).

Eric

Great
I don't know much about those, but it was 2 versions? one with buzzer, and one without?
dsk

PS slightly off topic but my phone from WWI looks like this:
(Norwegian made by Elektrisk Bureau)

[hatrick]

If I'm not mistaken, both of my phones are the Model A.  I think the Model B was pretty much the same with the addition of a telegraph key.

dsk - thanks for the detailed info on how to wire my 4-wire handset to the 3 wire phone box.  I'll give that a try on Saturday when I can start working on these again.

Here are some pictures of my phones.

[hatrick]

more pics...

[HowardPgh]

I have a Kellogg set like that. It has a telegraph key in it also.
I am missing the hookswitch on mine.(anybody have one to sell?)
Howard

[hatrick]

Howard,

I know this is probably pretty obvious, but us the handset hook just folded up into the box?

Eric

[HowardPgh]

Not folded back inthe box-sadly it's gone.-Howard

[hatrick]

So I tried wiring the 4-wire handset as dsk instructed above with one of the wires from the handset transmitter/microphone to the yellow terminal, one of the wires from the handset receiver to the green terminal and then I soldered the second wire from the transmitter/microphone and the second wire from the receiver together and attached the pair to the red terminal.  This seems to work ok but not great.  Wired this way, the 4-wire handset is only about 40% volume compared to the 3-wire handset and I still cannot hear myself when I am talking into it.  Is there any other options?  In looking at the 3-wire handset, it looks like the second wire from the receiver is attached to the transmitter/microphone terminal inside the handset before coming out to the phone hence the 3 wires out.  

Still no ringer on one of the phones. I'll try cleaning the contacts this weekend. The second phones ringer seems ok.

Also, since you mentioned the approx. 3 volts to power these, I hope I am ok using 3 c-cell batteries since that is what fits perfectly in the battery compartment.

Thanks,
Eric

[dsk]

If we simplify the diagram, some details will be more easy to understand.

The battery may be 3 cells forming 4.5 volts, so its probably right.
To test the handset separate, just connect a battery between Y and G (4.5V will be fine for the test) e.g. from the battery terminals on the phone. Then you should just hear yourselves in the handset.
If we deem the ringer to have high resistance to voice signals, equal to be ignored in the circuit, you will observe the need of a short circuit between L1 and L2 to hear yourselves.  Listening circuit will be L1--Hook sw---R--Receiver--G--Ind coil secondary ---L2  (L2--back to L1 has to be something)

The ringer circuit may have a bad capacitor, try to short the cap to test.

The inductor has a switch operated when cranked, and 2 connectors to the moving coil who need to be clean.

dsk

[hatrick]

I haven't had a chance to do much in terms of testing the handsets of the phones based on dsk's latest instructions but I will try to do that in the next couple of days so I can hopefully get the handsets taken care of.

An interesting development with the one phone with the problematic ringer.  I disconnected the two phones from eachother and the one phone that seems to be the problem cranked very smoothly and easily and it's own ringer seemed to be working great.  Good sound as you cranked the phone ringer.  As soon as I connected the two phones together, the one phone's ringer became much harder to turn and was no longer ringing either itself or the other phone.  It was receiving a pretty good ring from the other phone when the other phone was cranked.  Any ideas on why the ringer doesn't work when the two phones are wired together but works great when they are disconnected?

Thanks,
Eric

[dsk]

This is more difficult, but my it may be the switch on the inductor, if it stays closed it will be almost shorting the ringers. It will also be more heavy to turn the crank on the other phone tan without a connection between the phones, but not as heavy as a direct short.

dsk

[hatrick]

So am I correct in understanding that it may be the inductor on the phone that seems to be fine causing the problem?  I'm not even sure where the inductor is but is there any way to test it and or fix it?

Thanks,
Eric


P.S. sorry for my lack of electrical expertise.

[dsk]

So am I correct in understanding that it may be the inductor on the phone that seems to be fine causing the problem?  I'm not even sure where the inductor is but is there any way to test it and or fix it?

Thanks,
Eric


P.S. sorry for my lack of electrical expertise.

Experience is something s just coming, and suddenly you have some

With an ohm meter yous should have a  much lower reading if the switch stays closed. Since you have 2 telephones it should be easy to compare. Just measure between the 2 line terminals. (on hook position)

My guess is a reading of approx 40 ohms on the bad one, and unlimited or at least several thousand at the good one.

dsk

[hatrick]

I think I will have to pick up an ohm meter so I can test some of this stuff properly.  I'll pick one up in the next day or two since all I have is a volt/dwell/rmp meter for my car right now..

Thanks,
Eric

[dsk]

About getting the right meter, it has been an issue about whats good or not, if you are able to lend a meter, you buy a little time to make the right choice. An old fashioned analog meter may often be better than a lo cost digital one.  On the other hand I usually use my digital meter, and does only use the olde meter a few times each year.  I'm quite happy with my newest lo cost Chinese meter like this: http://tinyurl.com/chys59l.  I fried my old one trying to measure voltage who showed up to be far more than 1000V. (dangerous) and didn't want to spend lots on a new one. (approx $25, p&p incl.)

dsk