Acer Aspire 7420 Service Guide

Chapter 4103
Use the following procedure as a guide for computer problems.
NOTE: The diagnostic tests are intended to test only Acer products. Non-Acer products, prototype cards, or 
modified options can give false errors and invalid system responses.
1.Obtain the failing symptoms in as much detail as possible.
2.Verify the symptoms by attempting to re-create the failure by running the diagnostic test or by repeating 
the same operation.
3.Use the following table with the verified symptom to determine...

104Chapter 4
System Check Procedures
External Diskette Drive Check
Do the following to isolate the problem to a controller, driver, or diskette. A write-enabled, diagnostic diskette is 
required.
NOTE: Make sure that the diskette does not have more than one label attached to it. Multiple labels can cause 
damage to the drive or cause the drive to fail. 
Do the following to select the test device.
1.Boot from the diagnostics diskette and start the diagnostics program.
2.See if FDD Test is passed as the...

Chapter 4105
External keyboard
If any of these devices do not work, reconnect the cable connector and repeat the failing operation. 
Memory check
Memory errors might stop system operations, show error messages on the screen, or hang the system.
1.Boot from the diagnostics diskette and start the doagmpstotics program (please refer to main board.
2.Go to the diagnostic memory in the test items.
3.Press F2 in the test items.
4.Follow the instructions in the message window.
NOTE: Make sure that the DIMM is...

106Chapter 4
Check the Power Adapter
Unplug the power adapter cable from the computer and measure the output voltage at the plug of the power 
adapter cable. See the following figure
1.If the voltage is not correct, replace the power adapter.
2.If the voltage is within the range, do the following:
Replace the System board.
If the problem is not corrected, see “Undetermined Problems” on page 122.
If the voltage is not correct, go to the next step.
NOTE: An audible noise from the power adapter does not...

Chapter 4107
Check the Battery Pack 
To check the battery pack, do the following:
From Software:
1.Check out the Power Management in control Panel
2.In Power Meter, confirm that if the parameters shown in the screen for Current Power Source and Total 
Battery Power Remaining are correct.
3.Repeat the steps 1 and 2, for both battery and adapter.
4.This helps you identify first the problem is on recharging or discharging. 
From Hardware:
1.Power off the computer. 
2.Remove the battery pack and measure the...

108Chapter 4
Power-On Self-Test (POST) Error Message 
The POST error message index lists the error message and their possible causes. The most likely cause is 
listed first.
NOTE: Perform the FRU replacement or actions in the sequence shown in FRU/Action column, if the FRU 
replacement does not solve the problem, put the original part back in the computer. Do not replace a 
non-defective FRU.
This index can also help you determine the next possible FRU to be replaced when servicing a computer.
If the...

Chapter 4109
Index of Error Messages
Error Code List
Error CodesError Messages
006 Equipment Configuration Error
Causes:
1. CPU BIOS Update Code Mismatch
2. IDE Primary Channel Master Drive Error
(THe causes will be shown before “Equipment 
Configuration Error”)
010 Memory Error at xxxx:xxxx:xxxxh (R:xxxxh, W:xxxxh) 
070 Real Time Clock Error
071 CMOS Battery Bad
072 CMOS Checksum Error
110 System disabled.
Incorrect password is specified.
 Battery critical LOW
In this situation BIOS will issue 4 short...

11 0Chapter 4
System timer error RTC battery
Run BIOS Setup Utility to reconfigure system time, then 
reboot system.
System board
Real time clock error RTC battery
Run BIOS Setup Utility to reconfigure system time, then 
reboot system.
System board
Previous boot incomplete - Default 
configuration usedRun “Load Default Settings” in BIOS Setup Utility.
RTC battery
System board
Memory size found by POST differed from 
CMOSRun “Load Default Settings” in BIOS Setup Utility.
DIMM
System board
Diskette drive A...

Chapter 4111
Error Message List
No beep Error MessagesFRU/Action in Sequence
No beep, power-on indicator turns off and 
LCD is blank.Power source (battery pack and power adapter). See “Power 
System Check” on page 105.. 
Ensure every connector is connected tightly and correctly. 
Reconnect the DIMM.
LED board.
System board.
No beep, power-on indicator turns on and 
LCD is blank.Power source (battery pack and power adapter). See “Power 
System Check” on page 105.. 
Reconnect the LCD connector
Hard disk...

11 2Chapter 4
Phoenix BIOS Beep Codes
CodeBeepsPOST Routine Description
02h Verify Real Mode
03h Disable Non-Maskable Interrupt (NMI)
04h Get CPU type
06h Initialize system hardware
08h Initialize chipset with initial POST values
09h Set IN POST flag
0Ah Initialize CPU registers
0Bh Enable CPU cache
0Ch Initialize caches to initial POST values
0Eh Initialize I/O component
0Fh Initialize the local bus IDE
10h Initialize Power Management
11h Load alternate registers with initial POST 
values
12h Restore...