Centenary Neophone
PST Conversion

The Centenary Neophone can be converted to Plug and Socket but for the standard telephone (wired to diagram T.29849) there are two routes one could follow:-

  1. The capacitor will have to be physically removed as it is fitted to a circuit board (un-solder) and a new wire soldered to one of the tracks.  This makes the phone non-standard.
  2. The capacitor is short circuited by a soldered piece of wire and one of the dial leads is removed and connected to the line cord.  This retains the telephone as close to original and it is easier to convert back to standard than route 1.

You have to make your mind up as to which one you favour.

To convert to PST follow these instructions:-

Standard Telephone (T.29849)

Route 1 - Capacitor fully removed

  1. White of line cord to 4.
  2. Red of line cord to 7.
  3. Remove capacitor.
  4. Solder one end of a piece of wire to the circuit board track, where the capacitor was removed.  There will be two holes - it's the track that goes to one lead of the bell ringer.
  5. Connect the blue of the line cord to the other end of the wire and insulate fully.
  6. Remove the wire strap above terminals 4 & 5.
  7. Insert a 3.3k resistor between terminals 4 & 5.
  8. If a rectifier element is to be installed fit on terminals 6 & 2.

Route 2 - Capacitor short circuited

  1. White of line cord to 4.
  2. Remove the orange dial lead wire from dial terminal 3 and connect to the Red wire of line cord to 7. Insulate fully.
  3. Short circuit capacitor with a piece of wire soldered across the terminals.
  4. Connect the blue of the line cord to terminal 7.
  5. Remove the wire strap above terminals 4 & 5.
  6. Insert a 3.3k resistor between terminals 4 & 5.
  7. If a rectifier element is to be installed fit on terminals 6 & 2.

Kingston Communication variant 904 & 908 (T.34320)

  1. Completely remove the old line cord from all connected terminals.

  2. Either remove Metal Can 1.8uF capacitor from PCB or remove links marked like upside down horseshoe with line through (there are two of these) - it would be better to remove the links.

  3. Connect red wire of new line cord to terminal 7.

  4. Connect blue wire of new line cord to terminal 8.

  5. Connect white wire of new line cord to terminal 3.

  6. Insulate green wire of new line cord.

  7. Connect a 3.3k ohm resistor across terminals 3 and E (5).

 

Last revised: 28 July, 2006