Acer Aspire 8940 Service Guide

Chapter 4191
Troubleshooting
Common Problems
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...

192Chapter 4
Power On Issue
If the system doesn’t power on, perform the following actions one at a time to correct the problem. Do not 
replace non-defective FRUs:
Computer Shuts down Intermittently
If the system powers off at intervals, perform the following actions one at a time to correct the problem.
1.Check the power cable is properly connected to the computer and the electrical outlet. 
2.Remove any extension cables between the computer and the outlet.
3.Remove any surge protectors between the...

Chapter 4193
No Display Issue
If the Display doesn’t work, perform the following actions one at a time to correct the problem. Do not replace 
non-defective FRUs:
No POST or Video
If the POST or video doesn’t display, perform the following actions one at a time to correct the problem.
1.Make sure that the internal display is selected. On this notebook model, switching between the internal 
display and the external display is done by pressing Fn+F5. Reference Product pages for specific model 
procedures....

194Chapter 4
Abnormal Video Display
If video displays abnormally, perform the following actions one at a time to correct the problem.
1.Reboot the computer.
2.If permanent vertical/horizontal lines or dark spots display in the same location, the LCD is faulty and 
should be replaced. See “Disassembly Process” on page 50.
3.If extensive pixel damage is present (different colored spots in the same locations on the screen), the LCD 
is faulty and should be replaced. See “Disassembly Process” on page 50....

Chapter 4195
LCD Failure
If the LCD fails, perform the following actions one at a time to correct the problem. Do not replace non-
defective FRUs:
Start
Check LCD 
modu le?Swap 
LCD cable /LCD  panel
OK
NG
Check MB LCD 
con n ector an d 
cable ?
OK
Reassemble
Re-plu g LCD cable
OK
NG
Swap M/B 

196Chapter 4
Built-In Keyboard Failure
If the built-in Keyboard fails, perform the following actions one at a time to correct the problem. Do not replace 
non-defective FRUs:
STAR T
Keyboar d FPC
wel l connec te d?NoCo n n ec t
it  w el l
Ke yboa rd O K?NoReplace
keyboard
R epl ace  M /B 

Chapter 4197
TouchPad Failure
If the To u c h P a d doesn’t work, perform the following actions one at a time to correct the problem. Do not 
replace non-defective FRUs:
Start
Check M/B T/P 
FFCRe-assemble th e 
T/P  F F C  to   M/B
OK
NG
Ch eck 
To u c h P a d
OK
Swap/Reassemble 
th e T/P  board  or 
T/P  F F C
OK
NG
Swap M/B 

198Chapter 4
Internal Speaker Failure
If the internal Speakers fail, perform the following actions one at a time to correct the problem. Do not replace 
non-defective FRUs:
Sound Problems
If sound problems are experienced, perform the following actions one at a time to correct the problem.
1.Reboot the computer.
2.Navigate to Start´ Control Panel´ System and Maintenance´ System´ Device Manager. Check 
the Device Manager to determine that:
• The device is properly installed. 
• There are no red Xs or...

Chapter 4199
7.Select Speakers and click Configure to start Speaker Setup. Follow the onscreen prompts to configure 
the speakers.
8.Remove and recently installed hardware or software.
9.Restore system and file settings from a known good date using System Restore. 
If the issue is not fixed, repeat the preceding steps and select an earlier time and date.
10.Reinstall the Operating System.
11 .If the Issue is still not resolved, see “Online Support Information” on page 265.
Internal Microphone Failure
If...

200Chapter 4
b.Select Set up microphone.
c.Select the microphone type from the list and click Next.
d.Follow the onscreen prompts to complete the test.
8.If the Issue is still not resolved, see “Online Support Information” on page 265.
HDD Not Operating Correctly
If the HDD does not operate correctly, perform the following actions one at a time to correct the problem. 
1.Disconnect all external devices.
2.Run a complete virus scan using up-to-date software to ensure the computer is virus free. 
3.Run the...