( 2 ) the state of the phone and locked into the test on the same channel and the signal generator set ( Motorola phones use the test card can be locked into test status and channel ; special computer software to use original Nokia phones offer to enter the test status and lock the channel . )

( 3 ) the signal generator RF signal is injected into the phone's antenna port , and then use the spectrum analyzer observations phone receiver RF part of the whole process , observed spectral waveform and level value ( low-frequency part with an oscilloscope ) , and with the standard value compared in order to identify the point of failure .

2 repair transmission circuit

    Phone launch aspects of failure , without launch, launch shutdown , according to the following steps for testing:

( 1 ) so that the phone is in test mode and locked in one transmit channel ( eg channel 62 transmitter frequency is 902.4MHz).

( 2 ) with a spectrum analyzer to observe the emission spectrum and the handset level value path , and compared with the standard value, in order to identify the point of failure .

3 audio circuitry overhaul

    Failure audio circuits are the ringer , speaker mute , can not hear each other speak and so on. Such failures to find a very easy and intuitive to use an oscilloscope , due to the current high mobile phone audio circuitry degree of integration, so that more and more simple audio circuits from the maintenance point of view, just replace several related components can be found failures.

1, the cleaning method

    Mobile phone mobility is caused by damp and easy water main reason for the structure of the particularity of the phone ( contacts , reed more ) is the key cause of failure is bad , and as such , the mobile phone repair , and cleaning method appears particularly important. When cleaning, the entire motherboard will generally be lower ( better to remove the display ) , who put in an ultrasonic cleaner with anhydrous alcohol for cleaning , after cleaning , use a hair dryer before the power test machine .

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