BELLSET No. 1

A wooden boxed magneto bell with two external gongs used with C.B. or Automatic table telephones.

This Bellset was originally called the "Bellset, Magneto, C.B." and was fitted with a Bell, Magneto 1000ohms. This bell ringer was later changed to the Bell No. 1A unmounted.

The early cases had a small key lock on the front door, but this was later replaced by a spring loaded captive screw fitted to the left hand side of the casing.

The GPO also inherited a number of bellsets from the National telephone Company and these were also numbered Bellset No. 1.

It was fitted with a 2uf Capacitor, a 1000ohm Ringer (comprising of two 500ohm coils) and a two winding Induction Coil (primary coil is 17ohms and secondary coil is 26ohms).

Generally used with Telephones No. 2, No. 10 and No. 150 etc (Candlestick telephones).

The Bellset was also made in a number of iterations - please see table below. Many were adopted from the sale of the National Telephone Company to the GPO.

The wooden casing is called a Case No. 1 and could be constructed of American Walnut, Black Chuglam, Pyinma, Halou, Tasmanian Myrtle or African Mahogany.

Bellset No. 1 with Bias Spring, was also available for Telephones No. 76, No. 82 and No. 124. This variant used a "Bell No. 1A, unmounted, with Bias Spring" as the ringing mechanism. Probably marked "BS" on the rear of the case.

Click here for more information on Bias Springs.

The ringer mechanism is a "Bell No. 1 unmounted" and is a 1000 ohm magneto ringer, 16c/s only (AC). The Bell-gongs No. 2 are 2.5" / 64mm in diameter.

The differences between the Mark 234 and the Mark 235 appear to be either hard wiring the capacitor directly and not via the hinges or just relocating the capacitor into the main body of the Bellset.

Do not confuse this Bellset with a Bell No. 1A, which has a smaller case and comprises only of a bell ringer and two gongs.

This Bellset was universally used by the GPO with table telephones and recovered Bellsets were refurbished and reused. In many cases they were made into wall telephones.

Introduced circa 1908.

By 1946 this Bellset had been superseded by the Bellset No. 25.

This Bellset can difficult to find nowadays, but a conversion kit is now available to fit to any Wooden or Bakelite Bellset. Click here for more information.

The Bellset Includes:-
1 x Case No. 1.
1 x Bell No. 1A, Unmounted.
1 x Bell-gong No. 2, Oxidized.
1 x Bell-gong No. 2A, Oxidised.
2 x Washers, Locking 1-2BA.
1 x Capacitor, MC No. 102.
1 x Coil, Induction No. 14.
4 x Screws for fixing.

Bellset No. 1 Mark 235

Identifying a Bellset No. 1

	Mark
Includes	Blank	234/5	NT10	NT12	NT19
Bells No. 1, unmounted	1	1	-	-	-
Bells No. 11, unmounted	-	-	1	1	-
Bells NT No. 1002A	-	-	-	-	1
Coils Induction No. 3 or 14	-	-	1	1	1
Coils Induction No. 4 or 14	1	1	-	-	-
Condensers MC No. 2 or 30 (4⅜" x 1⅝" x 1⅝")	1	-	-	1	1
Condensers MC No. 3 or 30 (4⅜" x 1⅝" x 1⅝")	-	1	-	-	-
Condensers MC No. 6	-	-	1	-	-
Bell Gong No. 2	-	-	2	2	-
Bell Gong No. 3 (Aluminium)	-	-	2	2	-

The above was taken from the GPO Rate Book (1928).

Wiring Diagrams - LD 38 (Mark NT19), N501 (1919) and N501 (1929).

Drawing - Bellset - 1751 (Mark 235).
Drawing - Case - 7276.

The following manufacturers made some of these Bellsets:-
Ericsson - their model N3090.
GEC - their model K8175 with diagram numbered KS6724.
STC - their model 4060B (Mark 235).
ATM - (Mark 235) - with diagram numbered T3387.

UK Military number - YA2494.

Adjustment of Magneto bells

Click here for the difference between a Bell and a Bellset

Restoring wood

Use as a bell only

Whilst this Bellset is generally associated with a telephone, it can be wired up as a simple bell. It cannot be used with batteries as it is a magneto (AC) ringer.

Connect your wiring with either two wires or a telephone line cord. This will be country dependant.

These instructions are for the UK system and use a standard telephone cord:-

Locate the two terminal plates either side of the bell ringer.
Connect the white wire of the new line cord to the left hand terminal.
Remove the links between terminals T & L2 and E & L1.
Connect a 3.3k resistor between E and L2.
Connect the blue wire of the new line cord to terminal L2.
Insulate the red and green wires of the new line cord as these are unused.

Pictures

Pictures showing Bellset No. 1 Mark 235 with the capacitor (bottom of left hand picture)
and the Coil Induction No. 4 (above the capacitor)

Bellset No. 1 Mark 234
The capacitor is mounted on the Bellset door.
The wiring for the capacitor is connected to the main body wiring via the hinges.
The Bell ringer is fitted with a bias spring.
Made by Siemens Brothers their Number Q2217

Picture of Bellset No. 1 Mark 235 with Coil Induction No. 18
This Bellset has most probably been factory refurbished by the GPO as the Induction coil is of the
later type and the terminals are on the base, instead of on the bottom of the front casing.
Note the second paster diagram, pasted over the original paster

Early Bellset No. 1

These Bellsets below are early examples, they can be GPO or NT examples.
The capacitor in both styles, fits inside the base.

These were probably manufactured at the W.E. factory by B.T.M.C. of Antwerp