AT&T administration and, Installation And Maintenance Manual

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Adding a Shield to a
When you add an expansion carrier, you must install a
Power Supply Module
second Power Supply Module in it to power the additional
line and/or station modules. The second Power Supply
Module may induce excessive noise on the new line or
station module immediately to its right. Copper foil
shields can be installed to eliminate this noise. These
shields are packaged in the 391A Power Unit Shielding
Kit included with the expansion carrier.
Before installing the Power Supply Module on the
expansion carrier, install a copper-foil shield as follows:
1
2
3
4
5
6
Lay the Power Supply Module on a flat surface with
the right (as viewed from the front edge) side up.
Wipe the right side of the module free of any dust or
dirt.
Peel the backing paper from the smaller copper foil
shield to expose the adhesive.
Position the foil on the upper part of the module being
sure to tuck the foil tightly into the comer as shown in
Figure 2-18. Work out any air bubbles as you press the
foil firmly in place.
CAUTION:
Make certain of the position of the foil
before adhering it to the side of the module. Once
in place, the foil is difficult to remove.
Peel the backing paper from the larger copper foil
shield to expose its adhesive.
Position the foil on the lower part of the module as
shown in Figure 2-18. Work out any air bubbles as
you press the foil firmly in place.
2-70 Installing the Control Unit