Linesman's Telephone 704C circuit diagram
 

I have acquired a linesman's field telephone number 704C. The telephone is in good condition and seems to be working. The 704C has an extra push button switch to provide a 20mA line current. Part of the circuit diagram stuck to the lid is missing and the rest of the circuit diagram is in very poor condition. The user instructions label stuck to lid is also missing some of the text. I have managed to find the diagram for a 704B, but the 704B does not have the circuit for the 20mA line current. Does anyone have a circuit diagram / user instructions for the 704C telephone. Any help finding a diagram would be much appreciated.

Re: Linesman's Telephone 704C circuit diagram
 

Have a look on here.
http://www.samhallas.co.uk/repository/n_index/index.php NB- it's GPO n diagrams, where the diagram you want is no +100, in case of tle 704, you want diagram 804.

Re: Linesman's Telephone 704C circuit diagram
 

See page two of this.

Re: Linesman's Telephone 704C circuit diagram
 

Thank you for the PDF containing the diagram for the 704C. I can now check that the phone is working correctly especially the 20mA line current circuit and how it works in conjunction with the CB / LB mode switch.