GEC MURAPHONE
CONVERSION TO PST

Conversion of the early Muraphone (wired to diagram KS10287 Issue A)

The terminal layout of the phone is shown below - the terminals are marked in the plastic.

Using a standard BT line cord wire the phone as follows:-

1. Remove any link between E and L1.

2. White of line cord to terminal L1.

3. Red of line cord to terminal L2.

4. Green of line cord - spare - insulate.

5. Disconnect red on 2uf capacitor.

6. Connect the blue wire of the line cord to the red wire and insulated.

7. Fit a 3.3k ohm resistor between E and L1.

8. Fir a rectifier element between MR and R.

9. Check transmission and replace transmitter if bad.  Click here for more information.

Conversion of the later Muraphone K (wired to diagram KS10992 Issue C)

The terminals are marked on the terminal block.

Using a standard BT line cord wire the phone as follows:-

1. Remove the strap between 11 and 12.
2. Connect the 3.3k resistor between 11 and 12.
3. White of the line cord to 12.
4. Remove the strap between 13 and 14.
5. Red of the line cord to 14.
6. Blue of the line cord to 4.
7. Green of the line cord to 3.
   

Last revised: January 19, 2008