TELEPHONE MANUFACTURING Co. (TMC)
TELEPHONE S52597

TMC produced this compact telephone for Telephone Rentals and probably other suppliers. This telephones has two capacitors (in the same casing) an induction coil and a bell ringer, with 2 gongs, on the base plate.

Can be found with TR or Telematic embossed in the centre of the handset handle and TR Services printed on the dial label..

In the body of the phone is an 8 way style terminal array with only 6 or 7 terminal connections populated and unlike Ericsson and GEC compacts, is the only terminal block within the phone.  The terminal block has screws instead of nuts.  The internal diagram will advise if the circuit is 6 or 7 terminal.  When terminal 7 is used, it is hardwired to gravity switch hook spring 3.

The base plate accommodates the capacitor, the bell ringer, bell gongs (barrel shaped) and induction coil.  The base plate also has oblong slots covered with mesh, which stop insects and foreign objects entering the telephone.

The case is straight edged at the bottom, has a full size base plate and two cable entry holes on the rear, which have ebonite grommets.  Some models only have one cable entry hole in the case.

Very similar to the S52596.

The cylindrical capacitor, which is the GPO Capacitor M.C. 97, was introduced circa 1947, whilst PVC insulated wire was first used in telephones in the late 1940's.

Click here for more information on compact telephones.

Diagram S52597 (6 terminal type)

 

Diagram S52597 (7 terminal type)

How to convert this telephone to the UK PST System

6 terminal type
Using a standard UK line cord:-

1. Remove and discard the old line cord.

2. Feed the new line cord through the casing entry hole and tie it or knot it to the metal loop inside the phone.

3. Connect the White wire of new line cord to terminal 4.

4. Install a 3.3k resistor between 4 & 5.

5. Connect the Red wire of new line cord to terminal 6.

6. Connect the Green wire of new line cord - spare - insulate.

7. Disconnect the green wire on 2uf capacitor and connect this to the Blue wire of the new line cord (insulate with tape).

8. Check transmission and replace transmitter if bad and always fit a Rectifier element across the receiver on terminals 1 & 2.  Click here for more information.

7 terminal type
Using a standard UK line cord:-

1. Remove and discard the old line cord.

2. Feed the new line cord through the casing entry hole and tie it or knot it to the metal loop inside the phone.

3. Connect the White wire of new line cord to terminal 4.

4. Install a 3.3k resistor between 4 & 5.

5. Connect the Red wire of new line cord to terminal 6.

6. Connect the Green wire of new line cord - spare - insulate.

7. Disconnect the green wire on 2uf capacitor insulate with the end of the wire with tape.

8. Connect the Blue wire of the new line cord to Terminal 7.

9. Check transmission and replace transmitter if bad and always fit a Rectifier element across the receiver on terminals 1 & 2.  Click here for more information.

Additional Pictures

Rear view - note the twin cable entry holes with ebonite grommets

View of the base plate - 5 oblong sound exit slots covered with mesh

Internal view of the case - No components are mounted within the case
6 Terminal type

Internal view of the base plate showing components
6 Terminal type

Capacitor markings - In this case there is no date
S113550 is the TMC code for this capacitor

The "TR" symbol is found on the handsets of phones produced for Telephone Rentals

7 Terminal type

7 terminal type