Lenovo ThinkPad T550 User Manual page 122

2. Reconnect the external monitor to your computer.
3. Refer to the manual shipped with the external monitor to check the resolutions and refresh rates that
are supported.
– If the external monitor supports the same resolution as the computer display or a higher resolution,
view output on the external monitor or on both the external monitor and the computer display.
– If the external monitor supports a lower resolution than the computer display, view output on the
external monitor only. (If you view output on both the computer display and the external monitor,
the external monitor screen will be blank or distorted.)
• Problem: You cannot set a higher resolution than the present one on your external monitor.
Solution: Make sure that the monitor information is correct. If necessary, update the monitor driver.
• Problem: The screen is unreadable or distorted.
Solution: Make sure that:
– The monitor information is correct and the appropriate monitor type is selected. Refer to the solution
to the above problem.
– Make sure that an appropriate refresh rate is selected by doing the following:
1. Connect the external monitor to the monitor connector, and then connect the monitor to an
electrical outlet.
2. Turn on the external monitor and the computer.
3. Right-click on the desktop, and click Screen resolution.
Note: If your computer cannot detect the external monitor, click the Detect button.
4. Click the icon for the desired monitor (the Monitor-2 icon is for the external monitor).
5. Click Advanced Settings.
6. Click the Monitor tab.
7. Select the correct screen refresh rate.
• Problem: Wrong characters are displayed on the screen.
Solution: Did you follow the correct procedure when installing the operating system or program? If you
did, have the external monitor serviced.
• Problem: The Extend desktop function does not work.
Solution: Enable the Extend desktop function. See "Changing display settings" on page 39.
• Problem: If you use the Extend desktop function, you cannot set a higher resolution or higher refresh
rate on the secondary display.
Solution: Change the resolution and the color depth to lower settings for the primary display. Refer
to the solution to the above problem.
• Problem: Display switching does not work.
Solution: If you use the Extend desktop function, disable it, and change the display output location. If
a DVD movie or a video clip is playing, stop the playback, close the program, and then change the
display output location.
• Problem: The screen position on the external monitor is incorrect when that monitor is set for a high
resolution.
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User Guide