Blu VIVO 4.8 Service Manual
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BLU VIVO 4.8
Service Manual
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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
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1. Outline
1.1. Mobile Introduction
Product Hardware Definition
Base Chip Set
BB
MT6589
PMIC
MT6320
Transceiver
MT6167
Camera DSP/MMP
NA
RFPA
SKY77590
FM
MT6628
BT
MT6628
Audio
CODEC&PA
YD145
Memory
Samsung KMK8U000VM-B410
TP IC
Mxt224
Peripheral
Configuration
LCD
4.77"
Backlight driver
SGM3141BYD10G/TR
CAMERA
8 million pixel
Memory card
NA
Antenna
monopole
Basic
Performance
Indicators
Leakage current
≤ 90uA
Standby current
≤ 7mA
Call current as
maximum power
TBD
Board-level power
GSM
32.5dBm
DCS
29.5dbm
Board-level receiver
sensitivity
GSM
-108dbm
DCS
-108dbm
TRP
GSM
28.8dbm
DCS
28.0dbm
TIS
GSM
-105dbm
DCS
-106dbm
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System Block Diagram
CPU
MT6589
PMIC
MT6320
BATTRY
CAMERA
FM、BT、
WiFi、GPS
LCD&CTP
KEYPAD
MEMORY
MT6167
SKY77590
YD145
SPK
HP
REC
single SIM
CARD
MIC
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1.2. Motherboard Components Distribution
2. Signal Flow and Fault Analysis
2.1. RF Part
2.1.1. Block Diagram of the RF Section
RF Block Diagram
A
N
T
PA &
Ant Switch
SKY7759
0
Transceiver
MT6167
CPU
MT6589
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2.1.2. Signal flow of the RF Transmitting Part
2.1.2.1. Transmitting Path
Maintenance Flow Chart of the Transmitting Issue:
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（NO launch） Connect the PC and the phone with maintenance line,
then making the phone into the RF state with META software
Check Transceiver to see
if IQ signals exist.
Check the PA output to
see if there is RF signal in
Y
Check CPU
N
Check RF coaxial
switch or matching
network.
Y
Check the Transceiver
to see if there is RF
signal output.
N
VBAT,PA_EN,BAN
DSW_DCS,VAPC
Replace PA
Y
Check CPU
Y
Check Transceiver if LE、
SCLK/SDAT、
RFVCOEN、VCXOEN
have the correct signal.
N N
N
Y
Replace Transceiver
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2.1.2. Signal Flow of the RF Receiving Part
2.1.3.1. Receiving Path Components
Receiving path is shown in the following figure:
Maintenance flow chart of the receiving Issues：
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