NEC Versa 550 Series, Service Manual

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Contents v
Section 3 Hardware Functional Overview
Functional Block Diagram ........................................................................................... 3-2
System BIOS........................................................................................................ 3-3
System Processor.................................................................................................. 3-3
Major Functional Blocks.............................................................................................. 3-4
System Logic Controller .............................................................................................. 3-4
Memory Subsystem ..................................................................................................... 3-6
DRAM Memory ................................................................................................... 3-6
ROM Memory ...................................................................................................... 3-7
I/O Subsystem ............................................................................................................. 3-7
Video Subsystem ......................................................................................................... 3-7
Video Chipset Controller ...................................................................................... 3-8
External VGA Capability ...................................................................................... 3-9
Keyboard Subsystem ................................................................................................... 3-9
PCMCIA Controller and Sockets................................................................................. 3-10
Hard Disk Subsystem................................................................................................... 3-10
Floppy Disk Drive Subsystem ...................................................................................... 3-11
Pointing Device Subsystem.......................................................................................... 3-11
Power Subsystem ........................................................................................................ 3-11
AC Power Adapter ............................................................................................... 3-11
Internal Battery Pack ............................................................................................ 3-11
Powerboard .......................................................................................................... 3-12
LCD Inverter Board Assembly.............................................................................. 3-12
Section 4 Field Service Guidelines
Preventive Maintenance ............................................................................................... 4-1
Cleaning the Notebook’s Exterior ......................................................................... 4-1
Cleaning the Notebook’s Interior .......................................................................... 4-2
Protecting the Disk Drives .................................................................................... 4-2
Handling the Computer Battery Packs................................................................... 4-3
Maintaining the LCD Quality ................................................................................ 4-3
Cleaning the Trackball .......................................................................................... 4-3
Required Tools and Equipment.................................................................................... 4-4
Illustrated Parts Breakdown.................................................................................. 4-5
Field-Replaceable Parts and Assemblies ....................................................................... 4-8
Cover-Display LCD Assembly .............................................................................. 4-8
System Unit Assembly ................................................................................... 4-9