NEC PowerMate Professional 9000E Series User Manual page 128

7. Line the processor up with the guides in the retention
mechanism (see the following figure).
Locating retention mechanism guides
A – Guides B – Captive Nut Fasteners
8. Slide the processor into the retention mechanism. Ensure
that the alignment notch in the S.E.C. cartridge fits over
the plug in Slot 1. Push down firmly, with even pressure
on both sides of the top, until the S.E.C. cartridge is
seated.
4-30 Installing Options