Figure 9-42 Secondary Handset Microphone Circuit Diagram - Huawei U8815 Maintenance Manual

U8815
Maintenance Manual

Figure 9-42 Secondary handset microphone circuit diagram

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The primary and secondary microphones on the U8815 board collect different audio signals
by processing the MICs on the handset upper and lower parts, filtering the environmental
noises. The two microphones are powered by means of HSED_MICBIAS (headset MIC
PM8029 HSED_BIAS1), SND_MICBIAS (secondary MIC PM8029 HSED_BIAS2), and
MSM_MICBIAS (primary MIC 7227A MIC_BIAS).
Troubleshooting Process
Failure: No sound is picked up or transmitted during a call.
Solution:
Figure 9-43 shows the troubleshooting process for sound failure.
Issue 1.0 (2012-02-13)
Analysis
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
9 Principles and Failure Analysis
55