After 2 Nokia 6150 phones , after connecting the power supply, press the power button when the meter rises to 50mA, and then rose to 100mA, suddenly rose to about 300mA 250mA at the back swing back and forth , when the phone is switched to normal in looking for the network , when it finds the network, swing back around 100mA , then the backlight after quenching , swing back around 10mA .

    3 Nokia 8810 phone , connected to the power supply, press the phone power button , ammeter rise to 50mA, and then on to 100mAi sudden rise to 250mA 150mA at the back swing back and forth to find the network when the phone is found after returning to the network to swing back and forth at 80mA , back when the background lights out swinging at 10mA .

    Current reference other phones under different conditions are shown in Table 1-1.

 

Fourth, resistance method

    Resistance method is also more common in mobile phone repair , which features a safe, reliable , current method used to determine when the phone there are short-circuit fault , this time to find fault with a part of the resistance method is very effective , in addition, resistance method used to find resistance , transistor is normal, if there is a fault between the circuit breaker also ; very convenient.

Fifth, the signal tracking method

    Signal tracking method is mainly used to locate faults RF circuits can also be used to find the audio circuit. So this method generally requires RF signal generator (1 ~ 2GHz), spectrum analyzer (1GHz or more ) , oscilloscope (20MHzI: 2_L) and other instruments.

1 . Overhaul circuit

    Phone circuit fault , such as a weak signal or no signal, follow these steps to test :

( A ) a signal generator generates a radio frequency signal of one channel (e.g., channel receiver 62 is frequency 947.4MHz), the level value is generally set at -50dBm.

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