Compaq 400 486 DX2/40 MHZ 250 MB 4 MB 9.5 Personal Computer User Manual


 
o Battery pack -- The Nickel Metal Hydride battery pack is accessed
through the battery compartment.
To access the remaining system unit components, open the computer and
remove the keyboard assembly. These components include the following:
o Integrated trackball assembly -- This optical trackball is centrally
located at the bottom of the keyboard assembly. The assembly consists of
the trackball, retaining ring, and connector. The trackball assembly
connects directly to the system board and is secured by two screws. It
cannot be replaced with the mechanical trackball used in the Compaq
Models 400 and 410. The optical trackball and mechanical trackball are
not interchangeable among computer models.
o System board -- The system board is mounted directly to the system
chassis. All removable components connected to the system board, except
for the PC Card rails, must be removed prior to removing the system
board. The system board is unique and cannot be replaced by the one
used in the Compaq Models 400 and 410.
o Processor upgrade -- Models 420 and 430 are equipped with either a
DX4/75 MHz or a DX4/100 MHz processor on the system board. There are no
upgrade provisions for these models.
o Real-Time Clock Battery -- This battery is located in the left rear area
of the system board.
o PC Card rails -- The PC Card rails are replaceable and are secured by
two screws from the bottom of the system board and a clip on top of the
rails. The rails are not interchangeable with those used in Models 420
and 430. The clip is common between all models. The header attaches
directly to the system board and cannot be removed. The top and bottom
PC Card ejection levers are replaceable, but are not interchangeable
with those used in the Models 400 and 410.
o Diskette drive -- The diskette drive attaches to the system board by a
bracket and three screws. It is connected by a diskette drive cable and
LIF connector. The bracket attaches to the drive with four screws. The
drive is protected by an insulator between the system board and the
drive.