This Instruction describes the Telephone No. 145 and indicates the method of installation and maintenance.
Description
The
Telephone No. 145 supersedes Telephone No. 125 and has been
introduced for use in C.B. and auto areas to provide telephone facilities, on an incoming
basis only, at cab ranks and in other similar outdoor positions. The instrument has,
therefore, been designed to be weather resistant. A bell is not incorporated in the
instrument and it is, therefore, necessary to provide a Bell No. 67A
as a separate item.The Telephone No. 145 weighs approximately 30 lb. It has an enamelled cast-iron case, measuring approximately 15in by 6in by 5in overall, fitted with a spring loaded controlling device for the door. Contained in this cast iron case are a protector, terminal block and weatherproof container. The weatherproof container is mounted on the rear of a hinged panel, and encloses a Coil Induction, No. 27, Capacitor, MC No. 102 and gravity switch springs.
This hinged panel and associated apparatus is known as a Telephone No. 145, incomplete. The gravity switch mechanism, including the restoring spring, is fitted to the front of this hinged panel and the end of the switch arm is formed into a prong which supports the Telephone No. 164, which is fitted with a Mouthpiece No. 18, a Transmitter, Inset, No. 13 and a Cord, Instrument, No. 3/63, 18in.
Through the back of the outer case are four countersunk holes, tapped five/sixtenth inch Whitworth thread, for fixing purposes. Provision is made in both the top, and bottom, of the case for the entry of 0.75in conduit. When the telephone is issued, the conduit holes are fitted with wooden plugs. In addition, four holes (tapped No. 4 BA and fitted with screws) are provided in the top of the case for fixing a Bracket, Mounting, CC which is used to carry a Bell No. 67A. Removable enamelled steel plates, on which the exchange number should be sign written, are fitted on both sides of the telephone case.
INSTALLATION
Position
Although the instrument is weather-proofed, it is advisable to fit it in a sheltered position to give the longest possible service, and ensure the greatest comfort to the user.
When the telephone is to be fitted to a lamp standard or similar support, a suitable bracket should be made locally, and the telephone secured to this bracket by means of four bolts which should pass through the bracket into the tapped holes in the case.
Bells
Unless the telephone is to be fitted to a wall, it will be simpler to attach the bell directly to the telephone. To fix the bell in this manner, a Bracket, Mounting, CC, which includes all the necessary nuts and bolts for securing a Bell No. 67A to the bracket, should be requisitioned.
Wiring
Cable, I.R.V., Core T, 1-pair/12.5, Circular, should be used for wiring between the telephone and bell. This wiring (whether the bell is attached to the telephone case or not) and the external lead-in must be enclosed in Conduit No. 2. The lead-in conduit should be brought in at the bottom. of the case, and that carrying the wiring to the bell should be led out at the top of the case. Both conduits should be secured to the case by means of lock nuts. To prevent moisture from entering the conduits, the ends remote from the case should be made to point in a downwards direction, employing bends and elbows, if necessary. These ends should also be fitted with Bushes, Conduit, Brass to Prevent abrasion of the cables.
Labels
The exchange name and number should be sign written on one (or both) of the removable metal plates especially provided on the sides of the case.
Prevention of rust on conduit, screw-heads, etc. When the fitting work has been completed and the label(s) replaced, a coat of Paint, Black, for ironwork should be applied to all screw-heads, around all bolt-holes on the outside of the telephone case and to every joint in the conduit to prevent the formation of rust.
MAINTENANCE
Access is gained to the protector, the terminal block and to the weatherproof container housing the induction coil, capacitor and gravity switch springs by loosening the captive screw in the centre at the top of the inner panel and swinging the panel outwards and downwards on its hinges.
During a maintenance visit the correct action of the gravity switch plunger should be verified, and if the plunger tends to stick, a small drop of Graphite Colloidal in Oil should be applied to the candle-wick in the oil hole at the top of the plunger. The spring which controls the doors should also be examined and the spring (Part No. 2/SSP/529) should be replaced if it is weak or broken. The felt washer should be kept moist by the occasional application of one or two drops of Graphite Colloidal in Oil and the screw which fixes the spring device to the door should be examined and tightened if necessary.
PRECAUTIONS
(a) The induction coil, capacitor and gravity-switch springs are located in a watertight container fitted with a rubber gland in the interior of the telephone. This container must not be opened under damp atmospheric conditions. If necessary the whole panel (Telephone No 145, Incomplete) must be removed from the case by withdrawing the two panel securing screws at the bottom of the panel and disconnecting the cordage from the terminal block in the outer case. The panel should then be taken to the officer's headquarters or to the nearest exchange where the container can be opened to allow any repairs to be effected.
(b) The telephone is issued with cords of the cab tyre type (Cordage, Instrument No. 2/M and 3/M and Cords, Instrument, No. 3/63 KB, 18in). These cords are designed for use in damp situations and should not be replaced by other types, except as a temporary measure.
Replacements
(a) Cords Cordage, Instrument, No. 2/M and 3/M and Cords, Instrument, No. 3/63 KB, 18in should be replaced only by the same type of cordage and a spare stock of these items should be held.
(b) Capacitor, MC, No 102
will normally be available for replacement purposes.
(c) Gravity switch Springs
Access to the gravity switch springs is difficult, and where this item is found to be out of adjustment, the panel (Telephone No. 145, Incomplete) should be replaced under normal maintenance exchange procedure.
(d) Coil, Induction, No 27
Where a Coil, Induction, No. 27 requires to be changed, the replacement item should be taken from the spare stock held for use with 300-type telephones (see A 5201).
(e) Mouthpiece No 18
If replacement of the Mouthpiece No. 18 is necessary, and spares are not held locally, a Mouthpiece No. 15, supplies of which will be held for replacement purposes on Telephones No. 164, may be substituted as a temporary measure. A new Mouthpiece No. 18 should be obtained under the maintenance exchange procedure.
(f) ProtectorEarly issues of Telephone No. 145 were fitted with Protectors, G and, if these items are faulty, the telephone should be exchanged for n later issue of Telephone No. 145 fitted with Protectors and Fuses, No. 12.
(g) Transmitters, Inset, No. 13
These must always be used for replacement purposes (shown to the right).