Repairing 800 series Telecom/PMG phones

NUMBER CODE
The first digit "8",indicates an 800 series telephone. The second and third digits (01 to 99) identify type variations such as wall and table,automatic and C.B. manual,and will be used also to signify any successive models,e.g. 801 –Automatic table telephone with automatic transmission regulation. 811 –C.B. manual table telephone with automatic transmission regulation. The 4th digit is used to indicate special facilities,e.g. 8011
indicates an 801 telephone with press button recall.
GENERAL
800 series telephones comprise a number of easily replaceable units and sub-assemblies. When a fault develops,replace the defective unit or sub-assembly. Do not repair the printed circuit board or adjust the bell,dial or gravity switch.

SUB-ASSEMBLIES
Base Sub-assembly BSA-1. Metal base plate with rubber feet,two captive case-fastening screws and five screws to attach the printed circuit assembly and the bell assembly. Printed Circuit Assembly PCA-1. Printed circuit card on which are mounted gravity switch,induction coil,capacitor,fixed resistors,varistors,terminal studs and flexible "quick connect"links.

Polarised Bell Assembly PBA-1. Metal base combining sub-base for polarised bell movement and dial mounting brackets,bell movement,two steel gongs,loudness control and bell-cord. Case Assembly (Colour) CAC-1. Case moulding,extended number ring and clip,ventilator segment,2 plastic plungers (captive),2 case-securing clips.

Handset Complete (Colour) HCC-1. Handset body,transmitter inset and moulded transmitter adaptor,receiver 4T and moulded receiver adaptor,moulded receiver cap and transmitter cap. Dial Assembly. Dial,dust cover,gasket ring,mounting ring and dial cord.

Before commencing to replace sub-assemblies inside the telephone,unplug the telephone and take it to a convenient working position. When a subscriber requests that the plug on a normal straight line service be made captive,this should be done in the manner set out in the Technician’s Handbook,pages IA32 and 33. When it is necessary to replace the cover of a socket or plug,make sure that you securely tighten the cover-holding screw but do not overtighten or the plastic cover may be damaged. When you replace a defective –sub-assembly,place it in the container in which you obtained the spare unit and return it to your depot for despatch to the Workshops.

REPLACEMENT OF PRINTED CIRCUIT ASSEMBLY.

Replace the complete assembly when faulty –do not replace individual components. All cords are terminated with "quick connect"sleeves. To remove the conductor,grasp the upper portion of the metal sleeve with long nosed pliers and lever upwards using the other hand to hold down the base and as a fulcrum. Long nosed pliers are also best to replace the sleeves. Do not disconnect sleeves by straining on the conductor,and do not bend the terminals.

CORDS.
The telephone entry points of the line and handset cords may be reversed if required.
The conductors of the two cords should be twisted together inside the instrument,to keep them clear of the gravity switch. Line cords are available in 3 conductors (4’6",6′or 10′) or 6 conductors (4’6"only). New telephones are supplied with 3 conductor line cords. 6 conductor cords are fitted by Installation staff if the facility requires the use of more than 3 conductors.

To remove the dial,deflect the moulding shoe and lift the quick connect sleeves from the tags. Do not adjust the speed cr weight of the dial but replace it when defective. Defective dials should be returned to the Sifting Room with cords attached. Dials BTM type 71708A,71816 and BP0 No.21 have been supplied with 801 telephones. A standard A.P.O. dial for 801 telephone should be available in 1965. Pending the availability of a standard A.P.O. dial,Dial BTM type 71816 will be the only dial purchased as a replacement dial for the 801 telephone. When replacing dial BTM type 71708A or BPO No.21 the adaptor (number ring) must be replaced with an adaptor ABC-2. If the adaptor ADC-2 is not available the complete set of mouldings is to be changed. To remove the Dial Label Holder,-
1. Dial BTM Type 71706A and 71816 –insert a pin in the bottom of the plastic holder;press the pin,and at the same time,turn the label anti-clockwise.
2. Dial BPO No.21 –the dial label holder is lifted off using the suction cup which is supplied. The suction cup is stored behind the receiver inset and must be replaced in this position..

B27 Replacing the dial label and label holders-
1. BTM Dials –Replace the label holder on the finger plate so that the small hole lines up with the centre of the "0"finger plate hole. Hold the dial steady and rotate the label holder clockwise until it snaps into position.
2. BP0 21 Dials –Some BPO 21 dials have no spring behind the label to prevent it from turning. When replacing the label on such a dial,pack it out with a cardboard disc or secure it with a small amount of glue. The label holder presses into position.
BELL ADJUSTMENT
The loudness of the bell is adjusted by the knurled wheel on the base plate. This is the only adjustment of the bell permitted in the field as special jigs are required to enable the bell movement to be adjusted correctly. When a bell assembly is defective,replace it. The bell assembly mounts with only one screw and connects with "quick connect"tags. Make sure that the subscriber knows how to adjust the loudness of the bell. REFITTING TELEPHONE CASE
(i) Check that the cord conductors are properly terminated and are clear of the gravity switch arms and bell gongs and do not overhang the base plate to be pinched by the case.
(ii) Position the case over the dial so that the number ring is ready to fit around the neoprene dial gasket ring at the finger stop.
(iii) Press the rear of the case down on the base,watching that no cord conductors are caught.
(iv) Press forward on the rear and down on the front of the case near the finger stop to ensure that the number ring fits around the finger stop and gasket.
(v) Invert the telephone and fasten the two screws.