BLU Products BLU VIVO IV, Service Manual

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Page 2 of 22
Contents
1. OUTLINE ............................................................................................................... 3
1.1. Mobile Introduction ................................................................................................................................ 3
1.2. Motherboard Components Distribution ................................................................................................ 5
2. SIGNAL FLOW AND FAULT ANALYSIS ............................................................ 6
2.1. RF Part ..................................................................................................................................................... 6
2.1.1. Block Diagram of the RF Section ..................................................................................................... 6
2.1.2. Signal flow of the RF Transmitting Part ........................................................................................... 6
2.1.2.1. Transmitting Path ............................................................................. Error! Bookmark not defined.
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 .......................................................................................................................... 16
2.2.4.1 Analysis of the keyboard fault .................................................................................................... 17
2.2.4.2 Analysis of Display module circuit ............................................................................................. 18
2.2.4.3 FM Module ................................................................................................................................. 18
2.2.4.4 Camera Module ........................................................................................................................... 19
2.2.4.5 IO Interface ................................................................................................................................. 20
2.2.4.6 SIM Card Circuit ....................................................................................................................... 20 7
2.2.4.7 BT/WIFI/GPS Circuit ................................................................................................................. 21
2.2.4.8 G-sensor Circuit .......................................................................................................................... 21
2.2.4.9 M-sensor Circuit ..................................................................................................................... 22
2.2.4.10 Gyroscope Circuit ................................................................................................................... 22