Floppy Disk Drive Subsystem; Pointing Device Subsystem; Power Subsystem; Ac Power Adapter - NEC Versa 550 Series Service Manual

FLOPPY DISK DRIVE SUBSYSTEM

The Floppy Disk Drive Subsystem consists of an FDD controller provided by SMC
37C665IR and the built-in floppy disk drive. The floppy disk drive supports standard 3.5-
inch 720KB and 1.44MB mini-diskettes.

POINTING DEVICE SUBSYSTEM

The pointing device subsystem consists of the built-in trackball device on the system top
cover assembly and a pre-programmed Motorola G10 Lapkat micro-controller that inter-
faces the mouse device to the Motherboard. An external PS/2 port also supports the use of
an external PS/2 compatible mouse where the system automatically detects on system
power up and then disables the internal trackball.

POWER SUBSYSTEM

The Power Subsystem consists of the following major sections:
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External AC Power Adapter
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Internal Battery Pack

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Powerboard (on Motherboard)
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LCD Inverter Board (in LCD Panel Assembly)
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Power Conservation Logic (part of Motherboard)

AC Power Adapter

The computer is equipped with a universal AC power adapter that converts AC voltage (90
to 265VAC, 47 to 63Hz) into DC voltage used to operate the notebook and charge the
batteries.
Internal Battery Pack
The NEC Versa 550 Series notebooks utilizes NiMH (Nickel Metal-Hydride) that provides
DC power for the notebook (and for the NVRAM and real time clock battery on the Moth-
erboard) when the AC Adapter is not connected to the computer.
NOTE: Do not move the notebook when the
HDD LED is activated on the LCD status bar.
This protects the hard disk drive from any acci-
dental damage or loss of data.
Hardware Functional Overview 3-11