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In this lesson, we will learn the maintenance steps of the microphone circuit

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When the microphone or the related circuit of the microphone does not work,

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we first check whether it is the fault of the main microphone or the secondary microphone

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So how to distinguish the failure of the main microphone and the auxiliary microphone?

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First, make a call and make a call when the speakerphone is not on

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If the other party cannot hear the sound, it can be determined that the circuit of the main microphone is faulty

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Everyone should pay attention to this does not mean that the main microphone is broken,

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but the circuit of the main microphone is faulty.

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The line from the main microphone to the microphone leads to the large audio,

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including the large audio

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So how to judge the failure of the secondary microphone?

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Turn on the handsfree to make a call, if the other party cannot hear the sound,

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then this is a fault in the secondary microphone circuit

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The second step is to measure the ground value of the microphone data line,

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which should be measured from the end pin of the microphone

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According to the actual structure of the circuit, the main microphone is mostly on the small board of the tail plug

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At this time, we give priority to replacing the small board of the tail plug to eliminate it,

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or check whether the small board of the tail plug has serious water ingress

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Severe water ingress, it is basically determined that

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there is a problem with the circuit of the small board of the tail plug,

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which causes the main microphone to not work

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If the above is ruled out,

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it is necessary to replace the extension cable connecting the small board and the large board

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This cable is used to transmit the microphone signal

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There are many designs of Android phones,

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that is, the small tail plug board is connected to the big mainboard through an extension cable.

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After replacing the small board of the tail plug,

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if the fault of the main microphone still cannot be solved,

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it is necessary to find the socket on the mainboard to connect the microphone signal

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Find the signal pin of the microphone on the seat to measure the ground value

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If the capacitor is connected in series in the microphone line,

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the ground value measured at the end must be infinite

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For the analysis method of this point,

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we can refer to how to measure the ground value of the series capacitor mentioned before

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For capacitors in series, you can measure the ground value at the end of the capacitor connected to the large audio

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Usually the main microphone is more damaged,

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because it is welded on the small board of the tail plug

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There are more components in its circuit,

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and the probability of its failure is relatively high

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This needs to be flexibly changed according to the structure of the actual circuit.

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This is the circuit analysis of the main microphone

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The maintenance analysis method of the secondary microphone is the same as the second step

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Because the secondary microphone is directly soldered to the mainboard,

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it has two pins that go directly to the mainboard

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It is also to measure the ground value to see if there is any abnormality

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Observe the appearance first.

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If the microphone is obviously corroded by water, you need to remove it and re-solder it

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That's all for this lesson