Lenovo A859 Service-Handbuch - Seite 31

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Repair Manual of Lenovo S920 Mobile Phone

If it is possible to repair the complete set, the output power of each module on

transmission channel can be detected through spectrum analyzer probes when keeping the

phone in the constant state of maximum power. Under normal circumstances,

A. About GSM 33dBm and DCS/PCS 30dBm output power can be detected on the

output end of RF connector.

About

3dBm

output

C2102,R2105,C2101,R2102 of PA input end;

C. About 32dBm or 29dBm output power can be respectively detected on pin26

connection of PA output end;

D. About 3dBm output power can be detected on Transceiver (U2101) output end.

4.4 WCDMA forecast

Fault: RSSI fails

Cause: There are problems in receiving channel

Repair manner:

RSSI_cal

RSSI Fail？

Whether TX module U2102

and RF connector CON2101

are in cold solder joint?

Check whether Band1 and the

surrounding circuit devices are

in cold solder joint or partially

pasted

Fault: TPC fails

Cause: There are problems in transmission channel

Repair manner:

power

can

detected

Re-weld

matching

circuit