Lenovo ThinkCentre M71z, Hardware Maintenance Manual

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Monitor problems
Note: Many monitors have status-indicator lights and built-in controls for adjusting brightness, contrast,
width, height, and other picture adjustments. However, the controls vary from monitor type to monitor type.
Select your symptom from the following list:
• “Wrong characters appear on the screen” on page 43
• “The monitor works when you turn on the computer, but goes blank after some period of computer
inactivity” on page 43
• “The monitor works when you turn on the computer, but goes blank when you start some application
programs” on page 43
• “The image appears to be flickering” on page 43
• “The image is discolored” on page 44
Wrong characters appear on the screen
Symptom: Wrong characters appear on the screen.
Action: Have the computer serviced. For details, see “Additional information resources” on page 30.
The monitor works when you turn on the computer, but goes blank after some period
of computer inactivity
Symptom: The monitor works when you turn on the computer, but goes blank after some period of computer
inactivity.
Action: The computer is probably set for energy savings with the power-management feature. If the
power-management feature is enabled, disabling it or changing the settings might solve the problem.
If these actions do not correct the problem, run the diagnostic programs (see “Diagnostics” on page 51 for
instructions). If you need technical assistance, see “Additional information resources” on page 30.
The monitor works when you turn on the computer, but goes blank when you start
some application programs
Symptom: The monitor works when you turn on the computer, but goes blank when you start some
application programs.
Action:
Verify that the necessary device drivers for the application programs are installed. Refer to the documentation
for the affected application program to see if device drivers are required.
If these actions do not correct the problem, run the diagnostic programs (see “Diagnostics” on page 51 for
instructions). If you need technical assistance, see “Additional information resources” on page 30.
The image appears to be flickering
Symptom: The image appears to be flickering.
Actions:
• The monitor might be operating in a low-refresh rate display mode. Set the monitor to the highest,
noninterlaced refresh rate supported by your monitor and the video controller in your computer.
• The monitor might be affected by interference from nearby equipment. Magnetic fields around other
devices, such as transformers, appliances, fluorescent lights, and other monitors might be causing the
Chapter 5
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Troubleshooting and diagnostics
43