Lenovo ThinkCentre M79, Hardware Maintenance Manual

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1. Remove the new hardware option or software. If you must remove the computer cover to remove a
hardware option, ensure that you review and follow the electrical safety information provided with your
computer. For your safety, do not operate the computer with the cover removed.
2. Run the diagnostic program to ensure your computer is operating correctly.
3. Reinstall the new hardware option or software following the instructions provided by the manufacturer.
Audio problems
This section provides solutions to audio-related problems.
No audio in Windows
Solutions:
• If you are using powered external speakers that have an On/Off control, ensure the following:
– The On/Off control is set to the On position.
– The speaker power cable is connected to a properly grounded, functional ac electrical outlet.
• If your external speakers have a volume control, ensure that the volume is not set too low.
• On the Windows desktop, click the speaker icon in the Windows notification area. Then click Mixer .
Ensure that the mute speakers settings are not selected and none of the volume settings is set too low.
• Some models have a front audio panel you can use to adjust volume. If you have a front audio panel,
ensure that the volume is not set too low.
• Ensure that your external speakers (and headphones, if used) are connected to the correct audio
connector on the computer. Most speaker cables are color-coded to match the connector.
Note: When external-speaker or headphone cables are attached to the audio connector, the internal
speaker, if present, is disabled. In most cases, if an audio adapter is installed in one of the expansion
slots, the audio function built into the system board is disabled. Therefore, you must use the audio
connectors on the audio adapter.
• Ensure that the program you are running is designed for use in the Microsoft Windows operating system.
If the program is designed to run in DOS, the program does not use the Windows sound feature. The
program must be configured to use SoundBlaster Pro or SoundBlaster emulation.
• Ensure that the audio device drivers are correctly installed. See Windows Help and Support information
system for more information.
Sound comes from one external speaker only
Solutions:
• Ensure that the speaker cable is inserted completely into the connector on the computer.
• Ensure that the cable that attaches the left speaker to the right speaker is securely connected.
• Click the speaker icon in the Windows notification area. Then click the speaker icon on top of the volume
control. Click the Levels tab and ensure that the Balance settings are set correctly .
CD problems
This section provides solutions to CD-related problems.
An audio disc or AutoPlay-enabled disc does not automatically play when it is
inserted into a CD drive
Solutions:
• If you have multiple CD or DVD drives installed (or a combination of CD and DVD drives), try inserting the
disc into the other drive. In some cases, only one of the drives is connected to the audio subsystem.
Chapter 8
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Troubleshooting and diagnostics
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