Dial Replacement (Instructions For Trained Technician); Ordering Guide - Lucent Technologies 520B Manuel D'utilisation

Install the Switchhook Assembly by reversing the above procedure. Insert the new Switchhook Assembly
in place of the old one. Push the movable part of the new Switchhook Assembly to the Explosive
Atmosphere Wall Telephone set by tightening the four flat-head screws using an appropriate size
screwdriver. Depress and release the movable part of the Switchhook Assembly to ensure that it is
properly installed.
After ensuring that all defects due to any cause, even though seemingly slight, have been corrected,
reconnecting the line wires at the protector to return the Explosive Atmosphere Wall Telephone set to
service.

DIAL REPLACEMENT (INSTRUCTIONS FOR TRAINED TECHNICIAN)

To replace the dial, first make sure the telephone line wires are disconnected at the protector. Remove
the faceplate by loosening and removing the three front cover screws as described above. Loosen the
No. 8-32 Allen Setscrew until the locking pin pops out. The apparatus unit may now be screwed off the
base. Care should be taken to avoid contamination of the threads with dirt or grit. Remove the apparatus
unit to an area where the danger from explosive atmospheres does not exist. Loosen the terminal screws
securing each wire from the dial, taking care to note the terminal location of each wire color. Loosen the
screws securing the dial to the mounting bracket. Complete the screw removal as required. Carefully lift
the dial out of the telephone so the seal remains undamaged. Insert the replacement dial, taking care to
insure the seal remains in place and undamaged, and secure the dial to the mounting bracket. Secure the
dial wires to the correct terminal location for each wire color by reversing the above procedure.
WARNING: Damage of any type to any component of the set while replacing either a dial,
Switchhook Assembly, or Handset with Cord, will require the Explosive Atmosphere Wall
Telephone set to be returned to the Lucent Technologies Service Center for repair or
replacement.
To replace the apparatus unit, remove all dirt and grit from the threads of both base and apparatus unit,
apply anti-seize compound to threads, and screw the unit to the base with a minimum of eight turns until
the leaf springs of the base make contact with the apparatus unit. Align the apparatus unit with the base
to permit depression of the locking pin into the hole in the base. Depress the locking pin and tighten the
No. 8-32 Allen Setscrew. The cover may now be secured to the apparatus unit by means of the three
mounting screws.
After ensuring that all defects due to any cause, even though seemingly slight, have been corrected,
reconnect line wires at the protector.

Ordering Guide

2520B Telephone Set, 25320B-03 Black —
Comcode: 103873030
Handset, G11A4-Type (with cord) —
Comcode: 101942969
Handset, G11A9-Type (with cord) —
Comcode: 101942977
Touch-Tone Dial, 72H-3A2 —
Comcode: 106025323
Switchhook Assembly —
Comcode: 840404628
9