Acer Extensa 450 Maintenance Manual

							1.4 Product Overview
All members of the Extensa 450 Series are high performance notebooks powered by
the 75MHz IntelDX4 processor and Windows 95 tm Operating System software. 
As a standard feature, all members of the Extensa 450 family also contain the
following features:
·4MB of RAM memory (user-expandable to 32MB)
·128 bytes of battery-backed up CMOS RAM 
·512 KB of video RAM
·340 Million Byte Hard Drive (user replaceable)
·Support for one PCMCIA Type I or II option (Type III if floppy drive is removed
with option)
·Ergonomic keyboard with palm rest (2.7 mm travel); built-in touchpad pointing
device
·Most standard external device interfaces including serial, parallel, PS/2,
external VGA, and serial infrared wireless port 
·Removable 3.5, 1.44 MB Floppy Drive (second Lithium Ion battery or a type III
PCMCIA device can be installed in its place with option)
·Choice of LCD displays (10.4 Dual Scan Color or  9.4 Active Matrix Color
LCD).
·AC Adapter with autosensing (100 VAC to 240 VAC, 50 to 60 Hz); 34 Watts of
DC output power
·10.8 Volt, 2400 mAH capacity,  Nickel-Metal Hydride (NiMH) primary battery
pack
·Provisions for secondary 10.8V, 1460 mAH capacity, Lithium-Ion Battery Pack
(with removal of Floppy Drive)
·Power management features for longer portable operation away from AC power.
        
 General  Description 1-3 
						

							Figure 1-2  Extensa 450 Series Features
      
1-4  General  Description 
						

							1.4.1 External Ports
As shown in Figure 1-3, the notebook computer contains the following external
ports:
·Serial Infrared (SIR) Port for wireless connection with a similarly equipped
printer or computer
·9-Pin Serial Port for attaching any RS-232 type serial device to the Notebook
·15-Pin External VGA Monitor Port for attaching an external monitor
·6-Pin PS/2 Port to attach an external Keyboard or Mouse
·Second 6-Pin PS/2 Port for attaching an external Keyboard/Mouse 
·AC Adapter Connector for attaching the AC Adapter to the notebook
Figure 1-3  Notebook External Ports
        
 General  Description 1-5 
						

							1.4.2 Touchpad Pointing Device
All members of the Extensa family feature a built-in Touchpad pointing device
located near the center of the keyboard’s palmrest. With light presure, the cursor
can quickly be positioned to the desired point; a quick double tap on the Touchpad
and you have selected an object. Two select buttons (switches) are located along the
front edge of the notebook
.
1.4.3 Keyboard 
The Extensa Series Keyboard is an 83/84-key, IBM enhanced-type keyboard with
the standard character and function keys plus 12 programmable function keys (F1
through F12).
Using the Special Function (Fn) key which assigns multiple functions to keys, the
keyboard can emulate the IBM 101/102 keyboards using 83 keys (84 on
international models).
The keyboard has a 2.77 mm stroke and features a special keyboard interface chip
that can detect multiple levels of key input (good simulation of N-key rollover for up
to 10 keys).  
Some of the major features of the keyboard include:
·2.77-mm Key movement 
·Integrated numeric keypad
·“Inverted T Cursor Control Key layout
Figure1-4 Extensa Touchpad 
      
1-6  General  Description 
						

							The notebook keyboard is available in the following versions:
·U.S. English - This version (also known as the domestic version) has 81 keys
and is generally used in the United States and Canada.
·U.K. English - This version (also known as the international version) has 82
keys and is generally used in England, Germany, and other European
countries with the appropriate keycap changes.
nNote: The Extensa Series Notebook Computer User’s Reference Manual contains de-
scriptions of  keyboard special function keys. A six-pin Mini-DIN connector can at-
tach to either an external PS/2 keyboard (or 101 Keyboard via an adapter), PS/2
Mouse, or the optional PS/2 Numeric Keypad.
1.4.3.1   Controls and Indicators
As shown in Figure 1-6, Extensa Series Notebook Computers contain a set of three
buttons (switches) and five LED displays just above the keyboard including: 
·Power, Setup, and Standby/Suspend Buttons (Switches)
·Caps Lock indicator. This LED indicates that the keyboard is locked in the
uppercase mode. To switch to the lowercase mode, press the Caps Lock key.
·Num Lock indicator. This LED lights when you press the NumLk key to toggle
on the numeric keypad lock function. When the LED is On, the embedded
numeric keyboard keys generate AT-keypad characters and functions when
pressed in conjunction with the Shift key. When the indicator is Off, pressing
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Figure1-5 Extensa Keyboard
        
 General  Description 1-7 
						

							the Fn key with the appropriate keys provides cursor movement, paging and
other functions in the normal mode. 
·Scroll Lock indicator. This LED lights to indicate that the keyboard is locked
in the scroll mode.
·Hard Disk Drive Activity Indicator. Indicates when notebook is accessing the
hard drive.
·Standby Indicator. Lights when Notebook is in Standby mode.
1.4.4  Standard Power Features
Notebook power for the Extensa 450 Series Notebook Computers is provided by an
AC Adapter and a rechargeable 10.8 V, 2400 mAh Duracell nickel metal hydride
(NiMH) battery pack that installs in a power bay near the front of the notebook
(right side).
 A second lithium ion battery may optionally be installed in the Floppy Drive bay
when the Floppy Drive is removed from the Notebook. 
Figure1-6 Extensa Series Controls and Indicators
      
1-8  General  Description 
						

							All members of the Extensa 450 family feature TI’s patented power management
subsystem (hardware and software) that provides longer portable operation and
protection of files during low battery conditions.
1.4.5  Wireless Connection With Serial Infrared Port
The Extensa series notebooks are equipped with a Serial Infrared (IR) port  that
offers wireless communication with a variety of IRDA-compliant devices made by
other manufacturers.
nNote: Prior to communicating with an external device equipped with a serial  infra-
red interface, the appropriate third-party drivers must be installed on your note-
book.
1.4.6 Preloaded Software
All members of the Extensa 450 Notebook family are preloaded with the Windows
95 Operating System. In addition, Extensa Models 455 and 455T come standard
with the following application packages installed:
·Microsoft Works
·Quicken SE
·Lotus Organizer
·Microsoft Entertainment Pack No. 4
1.4.7   Notebook Expansion Capabilities
Expansion capabilities built into the Extensa notebook series include:
·User installable expansion RAM memory (to a maximum of 32 MB)
·By removing the floppy drive, you can add either a second battery pack or a
Type III PCMCIA device with option.
·A Cable Connect PS/2 Numeric Keypad option, P/N 2581381-0001, can be
attached to either of the two external PS/2 Ports.
·A parallel device can be attached to the notebook’s external 25-pin parallel port
(EPP/ECP compatible).
·With the port adapter installed (supplied with the notebook), the notebook’s
expansion bus is adapted to provide the following external ports:
–Serial RS-232 Port for attaching any serial device
–External VGA Port for driving an external color monitor
–Second PS/2 Port for attaching an external keyboard or mouse
        
 General  Description 1-9 
						

							·Third Party External PS/2 keyboard (or external mouse)
1.5  Standard Test Features 
The Extensa Series Notebook Computers use modular design and built-in test
features to reduce the mean time to repair. A power on self-test automatically
verifies the operational state of the primary circuits and a powerful suite of
diagnostic tests are available to further test selected parts of the system.
1.6  Notebook Assemblies and
Subassemblies
The Extensa Series Notebooks are modular in design and can be disassembled for
maintenance purposes using a standard set of flat-bladed, Phillips-head and
hexagonal screwdrivers. The major assemblies that comprise a typical notebook in
the Extensa family are shown in Figure 1-7 and briefly described in the following
paragraphs.
Figure 1-7  Notebook Assemblies
      
1-10  General  Description 
						

							1.6.1 Cover-Display Assembly
The Cover -Display Assembly contains the LCD screen and associated high voltage
power supply and video circuitry. The Cover -Display Assembly contains three
field-replaceable components including:
·LCD Assembly
·Inverter Board 
·Slide Pot/Converter Board
The Cover -Display Assembly attaches to the System Base Assembly through four
top mounted screws and six  mounting screws on the bottom of the computer.
1.6.2  System Base Assembly
As shown in Figure 1-7, the majority of the notebook’s field replaceable units (FRUs)
are located in the system base assembly. These FRUs include:
·Main Board Assembly
·Hard Disk Drive Assembly
·Memory Board Assembly
·Up to two Dual Inline Memory Modules
·Serial Infra-red Board Assembly
·Floppy Drive Assembly
·Secondary Battery Board Assembly
·Power Supply Board Assembly
·Battery  Pack Assembly
·Top Case Assembly
·Touchpad Assembly
·Keyboard Assembly (removed in Figure 1-7 for clarity)
·Battery Board Assembly
        
 General  Description 1-11 
						

							1.7  Extensa 450 Series Notebook
Specifications
Specifications for the Extensa 450 Series Notebooks are provided in Table 1-6.
Table 1-6   Extensa 450 Notebook Features
Specifications Models 450/450T Models 455/455T
Memory:
Standard:4MB 4MB
Maximum32MB 32MB
Display
LCD Type:
10.4 Dual Scan Color 9.4 Active Matrix
Color 
Simultaneous LCD/Ext.
VGAYes Yes
Video RAM Size:512 KB 512 KB
Video BusVLBUS with Graphics
AcceleratorVLBUS with Graphics
Accelerator
Keyboard/Pointing
Device, 
Ergonomic KeyboardYes Yes
Built-In TouchpadYes Yes
Storage
Floppy Drive: 3.5, 1.44MB 3.5, 1.44MB
Hard Drive: 340 Million Byte 340 Million Byte
Interfaces
Serial (RS232) PortYes (Port Adapter) Yes (Port Adapter)
Parallel Port
(EPP/ECP), Ye sYes
External VGA PortYes (Port Adapter) Yes (Port Adapter)
External PS2 PortsYes (2nd PS/2 Port on
Adapter)Yes (2nd PS/2 Port on
Adapter)
Serial Infrared PortYes Yes
PCMCIA SupportType I/II (III Optional) Type I/II (III Optional)
      
1-12  General  Description