Northern Telecom BCS35 Replacement Manual page 35

Procedure 3–1
EPROM IC installation procedure
Step Description
1 Locate the two EPROM ICs on the
circuit pack.
2 Gently pry the EPROM IC from its
socket and set it aside. Use a gentle
rocking motion, alternately lifting each
end a little at a time to avoid bending
the pins.
3 Remove the new EPROM IC from its
packing material and place it on a
smooth flat surface so the pins are
facing down and the coded
identification label can be read from
the top.
4 Position the marked end of the new IC
over the marked end of the notch and
carefully insert the pins into the
socket.
5 Apply firm, even downward pressure
on the EPROM IC until it is fully
seated in the socket.
6 Do not remove the coded label from
the IC.
CAUTION
Since all DPP circuit packs are static sensitive, be
careful when handling them.
2
(continued)
DPP Card Replacement Guide BCS35 and up
EPROM circuit pack 19
1
Notes
This IC is labeled with a
coded number for
identification.
Use an IC extractor tool or a
small blade regular
screwdriver. Do not throw the
EPROM away; return it to NT.
Use this protective package
to store the old EPROM IC
until verifying the new one.
Notches or dots identify the
location of pin 1 on both ICs
and IC sockets.
The new IC may be supplied
with 24 or 28 pins. If the IC
l it
has 24 pins, instal to the
rear of the 28–pin socket.
IC–pin 1 lines up over
socket–pin 3.