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Plain Jane wood wall phone-Inherited

Started by WesternElectricBen, January 05, 2013, 04:21:43 PM

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WesternElectricBen

#15
Here are some pictures of the schematic: There are different viewing angles of the same sketch
Ben

dsk

Great  :D
It should work if you do this:
1: Remove the generator handle (just to ensure you not sends current out on the line.)
2: Move GN from receiver to 4/B (Disconnect battery)
3: strap YL/B to GN

4: Connect the telephone line to L1 and GN (polarity doesn't matter)

Now it should work, please report back how it sounds.


If you want to know what you have done now, you have swapped Transmitter and Receiver circuits and got a kind of anti side-tone bridge.
The DC current will mainly go trough the transmitter and the coil winding 1-2. The coil winding  5-6 lets a little bit of the dc pass, but has a main function as an anti side-tone balancing network. The receiver will be connected to the coils winding 3-4 who acts as the secondary winding of the transformer.  The function will be about as in the Siemens W48, but with slightly less good impedance matching.

Since you connects the line to terminal GN, the capacitor acts as a DC blocker and lets the ringer work only when lo frequency current are applied.

If you don't move remove the handle of the generator or in other ways prevent using the generator, you may send out ringing current on the line. This current may be tough for the other equipment. e.g the exchange. So remove this handle.

When you have got the circuit working, we may look at a way to change it so you only rings the bells on that telephone.

dsk


dsk

It is actually even a simpler way to do this.

Keep using batteries for the transmitter, Connect the telephone line to L1 and GN/6.
It should work here, but we have not protected your receiver from DC current.
This is not important, if you don't want to use it quite much, on the other hand it is solved by moving the receiver cord (Brown/Black) from GN/6 to L2.