Lenovo i909 Manual de manutenção - Página 27

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I908 Mobile Phone Maintenance Manual

Check whether or not there is pseudo soldering at L2108 and L2109 of the RF output

of PA;

V_ramp signal control circuit of PA:If there is pseudo soldering or disconnection

among R2103 (10K ohm), R2104 (18K ohm) and capacitor C2105(220pF), there will

be no power output from the PA.

Transceiver (U2101)

Check the power supply voltage of the transceiver (U2101). C2103, C2131, C2142, C2144,

C2147 and C2154are the filter capacitors of the transceiver power supply terminal. Check

the voltage at the connections between these capacitors and the transceiver. Then

check the peripheral circuit for possible pseudo soldering.

If the condition of the unit allows, it can be put into normal mode with full power output. Use

a frequency spectrometer analyzer to measure the output power of the various modules on the

launch circuit.Normally:

Power output of about 33dBm of GSM or 30dBm of DCS can be detected at the

A．

power output terminal of the antenna connector.

Power output of about 33dBm of GSM or 30dBm of DCS can be detected at the

B．

connecting point between the antenna switch power output terminal pin9 and

C2108;

Power output of about 32dBm and 30dBm can be respectively detected at the

C．

joint of pin 8 and pin 9 of output terminal of PA;

D．

Power output of around 4dBm can be detected at pin38 and pin39 of the transceiver

output terminal.

This should be helpful in determining the nature of the problem. Please deal with the

problem accordingly.

LENOVO

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