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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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13th Feb 2019, 12:12 am | #1 |
Diode
Join Date: Feb 2010
Location: Oldham, Greater Manchester, UK.
Posts: 5
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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.
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19th Feb 2019, 12:06 am | #2 |
Nonode
Join Date: Oct 2014
Location: West Midlands, UK.
Posts: 2,181
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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. |
19th Feb 2019, 12:15 am | #3 |
Octode
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
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Re: Linesman's Telephone 704C circuit diagram
See page two of this.
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20th Feb 2019, 2:54 pm | #4 |
Diode
Join Date: Feb 2010
Location: Oldham, Greater Manchester, UK.
Posts: 5
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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.
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