Page 2 of 24
Contents
1. OUTLINE............................................................................................................... 3
1.1. Mobile Introduction ................................................................................................................................3
1.2. Motherboard Components Distribution................................................................................................5
2. SIGNAL FLOW AND FAULT ANALYSIS............................................................ 5
2.1. RF Part .....................................................................................................................................................5
2.1.1. Block Diagram of the RF Section .....................................................................................................5
2.1.2. Signal flow of the RF Transmitting Part ...........................................................................................6
2.1.2.1. Transmitting Path..............................................................................................................................6
2.1.2. Signal Flow of the RF Receiving Part...............................................................................................8
2.1.3.1. Receiving Path Components .........................................................................................................8
2.2. Baseband part........................................................................................................................................10
2.2.1 Block diagram of the Baseband part....................................................................................................10
2.2.2 Power Management............................................................................................................................. 11
2.2.3 Audio Section......................................................................................................................................12
2.2.3.1 Audio Codec Circuit ...................................................................................................................12
2.2.3.2 MIC& Receiver Loop .................................................................................................................13
2.2.3.3 Headset Loop ..............................................................................................................................14
2.2.4 Baseband Fault issues..........................................................................................................................15
2.2.4.1 Analysis of the keyboard fault ....................................................................................................16
2.2.4.2 Analysis of Display module circuit.............................................................................................16
2.2.4.3 FM Module .................................................................................................................................17
2.2.4.4 Camera Module...........................................................................................................................17
2.2.4.5 IO Interface.................................................................................................................................18
2.2.4.6 SIM Card Circuit.......................................................................................................................187
2.2.4.7 BT/WIFI/GPS Circuit .................................................................................................................19
2.2.4.8 G-sensor Circuit..........................................................................................................................19
2.2.4.9 M-sensor Circuit .....................................................................................................................20
2.2.4.10 Gyroscope Circuit...................................................................................................................20
