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...

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...

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...

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...

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,...

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...

·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...

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...

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...