Acer Aspire 7420 Service Guide

Chapter 253
BIOS Flash Utility
The BIOS flash memory update is required for the following conditions:
New versions of system programs
New features or options
Restore a BIOS when it becomes corrupted. 
Use the Phlash utility to update the system BIOS flash ROM.
NOTE: If you do not have a crisis recovery diskette at hand, then you should create a Crisis Recovery 
Diskette before you use the Phlash utility.
NOTE: Do not install memory-related drivers (XMS, EMS, DPMI) when you use the Phlash.
NOTE: Please...

54Chapter 2
Remove HDD/BIOS Utility
This section provide you with removing HDD/BIOS method:
Remove HDD Password:
If you key in wrong HDD password for three time, “HDD password error code” would display on the 
screen. See the image below.
If you need to solve HDD password locked problem, you can run HDD_PW.EXE
1.
Key in “hdd_pw 15494 0”
2.Select “2”
3.Choose one upper-case string
Reboot system and key in “0KJFN42” or “UVEIQ96” to HDD user password. 

Chapter 255
Remove BIOS Password:
If you key in wrong Supervisor Password for three time, “System Disabled” would display on the 
screen. See the image below. 

56Chapter 2
If you need to solve BIOS password locked problem, you can run BIOS_PW.EXE
1.
Key in “bios_pw 14452 0”
2.Choose one upper-case string
Reboot the system and key in “qjjg9vy” or “07yqmjd” to BIOS user password. 

Chapter 257 

58Chapter 2 

Chapter 359
This chapter contains step-by-step procedures on how to disassemble the notebook computer for 
maintenance and troubleshooting.
Disassembly Requirements
To disassemble the computer, you need the following tools:
Wrist grounding strap and conductive mat for preventing electrostatic discharge
Flat screwdriver
Philips screwdriver
Hex screwdriver
Plastic flat screwdriver
Plastic tweezers
NOTE: The screws for the different components vary in size. During the disassembly process, group the...

60Chapter 3
General Information
Pre-disassembly Instructions
Before proceeding with the disassembly procedure, make sure that you do the following:
1.Turn off the power to the system and all peripherals.
2.Unplug the AC adapter and all power and signal cables from the system. 
3.Place the system on a flat, stable surface. 
4.Remove the battery pack.
Disassembly Process
The disassembly process is divided into the following stages:
 External module disassembly
 Main unit disassembly
 LCD module...

Chapter 361
External Module Disassembly Process
External Modules Disassembly Flowchart
The flowchart below gives you a graphic representation on the entire disassembly sequence and instructs you 
on the components that need to be removed during servicing. For example, if you want to remove the main 
board, you must first remove the keyboard, then disassemble the inside assembly frame in that order.
Screw List
ScrewPart No.
A M2.5 x L6 86.00E33.736
B M2 x L4 86.00A02.140
C M2 x L4 86.9A552.4R0
G M3 x L4...

62Chapter 3
Removing the Battery Pack
1.Turn base unit over. 
2.Slide the battery lock/unlock latch to the unlock position. 
3.Slide and hold the battery release latch to the release position, then remove the battery from the main 
unit.