AC Repair and Adjustment Procedures
FRP 12: Clock Wire Replacement
HMM-168-A
Cray Research/Silicon Graphics Proprietary
79
7.
Remove the clock module and the PEM where the defective cable
connects. Then remove additional modules to provide clear and safe
access to these rails. Refer to
FRP 5
. Put the modules in a protected
location that is ESD safe.
8.
Record the location of the defective wire.
Complete
through
for one end of the clock wire.
9.
Locate the rail connector to which the wire connects (for example,
connector zag), and identify the pin location of the wire (for example, pin
location zag04). Record the locations.
10. Use tweezers or your fingers to carefully remove the foam plug (P/N
57176200) from the slot where the clock wire enters the rail. (Each
connector slot contains an oval piece of foam, which tears easily.)
Figure 29. Connector Foam (Plug)
11. To aid you in dropping the connector into the card cage, loosen the wires
that plug into the connector where the defective wire is located. In other
words, remove tie straps that secure the wires to the wire rack in that
cabinet. Do not unbundle the wires.
12. Place ESD-safe foam or plastic in the bottom of the card cage to catch any
screws, etc., that you might drop in subsequent steps.
13. Use the 0.05-in. hex wrench to remove the 2 hex screws (and brass spacer
if applicable) that secure the connector to the rail. Then loosen (but do not
remove) the remaining hex screw in the adjacent connector that is closer
to the power supply. Refer to
. Be careful not to lose any screws;
set the screws in a secure location.
NOTE: This figure shows how wires pass through the slots in the foam.