Digital Equipment DECstation 212LP, Service Manual

Page: 65 / 91

3–22 FRU Replacement
3.2.12 Math Coprocessor Replacement
Replace the math coprocessor as follows:
1. Remove the cover (Section 3.2.4) and open the system unit
(Section 3.2.5).
2. Locate the math coprocessor on the main logic board
(Figure 3–11 and Figure 3–12).
3. Remove the math coprocessor as follows:
• DECstation 212
LP
: Use a small, flat-blade screwdriver and
alternately lift each end of the coprocessor. (Figure 3–11).
• DECstation 316
SX
and DECstation 320
SX
: Use a special
tool to simultaneously lift each corner of the coprocessor.
(Figure 3–12).
NOTE
While lifting the coprocessor out of the socket be
careful not to damage it or the socket, or bend any
pins.
4. Before installing the new math coprocessor, straighten any
pins (if necessary) so they align with the holes in the socket.
5. Make sure pin 1 of the math coprocessor is aligned with pin 1
of the socket.
NOTE
Facing the front of the DECstation 212
LP
, the pin 1
location is indicated by a dot near the lower left corner
of the socket (Figure 3–11).
Facing the front of the DECstation 316
SX
and
DECstation 320
SX
, the pin 1 location is indicated by
a numeral 1 near the lower right corner of the socket
(Figure 3–12).
6. Install the new math coprocessor in the socket by alternately
pressing each end into the socket. Do this until it is firmly
seated in the socket (Figure 3–11 and Figure 3–12).