Compal NBLB2, Service Manual

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To determine if the computer‟s built-in speakers are functioning properly, perform the
following procedures. Figure 6-9 outlines the process. First adjust the speaker volume
to an appropriate level. Start with Procedure 1 and continue as instructed.

Procedure 1: Audio source test

Procedure 2: Earphone test

Procedure 3: Connection check

Procedure 4: Replacement check
10.1 Procedure 1 Audio source test
Try different audio sources (e.g. an audio CD and digital music file) to determine
whether the fault is in the speaker system or not. If not all sources have sound
problems, the problem is in the source devices. If all have the same problem,
continue with Procedure 2.
10.2 Procedure 2 Earphone test
Connect a set if earphones or external speakers. If these function correctly, go to
Procedure 3. If they do not function correctly, the system board may be defective or
damaged. Replace it with a new one.
10.3 Procedure 3 Connection check
Disassemble the computer following the steps described Replacement Procedures
and make sure the speaker cable is firmly connected to the system board. If the
stereo speakers are still not functioning properly, go to Procedure 4.
10.4 Procedure 4 Replacement Check
If the stereo speakers don't sound properly, the stereo speakers may be defective or
damaged. Replace them with new ones. If the stereo speakers still do not work
properly.