Acer Altos R720 Series, User Manual

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5 Troubleshooting 144
• Make sure the memory modules comply with the system
requirements.
• Make sure the memory modules have been populated according
to the system requirements.
• Remove and reseat the memory modules.
• Make sure the CPU comply with the system requirements.
• Make sure the CPU is populated according to the system
requirements.
If you are using a video controller board, do the following:
1 Verify that the video works using the onboard video controller.
2 Verify that the video controller board is fully seated in the
mainboard connector.
3 Reboot the system for changes to take effect.
4 If there are still no characters on the screen after you reboot the
system and POST emits a beep code, write down the beep code
you hear. This information is useful for your service representative.
5 If you do not receive a beep code and characters do not appear,
the video display monitor or video controller may have failed.
Contact your service representative or authorized dealer for help.
Characters are distorted or incorrect.
Check the following:
• Are the brightness and contrast controls properly adjusted on the
video monitor? Refer to the documentation that came with the
video monitor.
• Are the video monitor’s signal and power cords properly
connected.
• Is the video monitor working correctly when plugged into a
different system?
System cooling fan do not rotate properly.
If the system cooling fan is not operating properly, it is an indication of
possible system component failure.