Apple PowerBook (Duo 270C) - Manual (Page 244)

If you eject the computer manually while it is turned on, the
computer turns itself off. You will lose any information you did
not save.
When the dock is locked, you can’t use the square hole.
Installing a NuBus card
Installing a NuBus card in the Duo Dock is a technically
challenging procedure. We recommend that you attempt it only
if you are comfortable working with electronic equipment. You
should read all of the following instructions before you begin. If
the procedure sounds like something you don’t want to do
yourself, any authorized Apple service provider can install a
NuBus card for you.
Getting ready
You need the Duo Dock, a NuBus card, and a flat-blade
screwdriver.
v If your system is already set up: Turn off, disconnect, and
remove all equipment attached to the dock, but do not
unplug the power cord that connects the dock to an electrical
outlet or power strip.
v
228 Chapter 13: Building a PowerBook Duo System