Acer Aspire one 521 Series, Service Manual, Page: 123 / 177

Chapter 4 113
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.
2. Make sure the computer has power by checking at least one of the following occurs:
• Fans start up
• Status LEDs light up
If there is no power, see “Power On Issue” on page 112.
3. Drain any stored power by removing the power cable and battery and holding down the power button for
10 seconds. Reconnect the power and reboot the computer.
4. Connect an external monitor to the computer and switch between the internal display and the external
display is by pressing
Fn+F5 (on this model).
If the POST or video appears on the external display, see “LCD Failure” on page 115.
5. Disconnect power and all external devices including port replicators or docking stations. Remove any
memory cards and CD/DVD discs. Restart the computer.
START
Power On ? No
Go to No Power
troubleshooting
step
Replace external
DDRAM module
Remove and
replace thermal
module
Replace the
main board
Reconnect
SDRAM Module
LCD Module OK?
Replace LCD
Panel and
Cable
Ext. DDRAM module
connected properly?
Ext. DDRAM
module functional?
CPU Thermal
Module properly
connected?
No
No
No
No