Micromax A74 L1 User manual

A74 L1&L2
service manual

2
content
1、Product introduce..………..p3-p4
2、Disassembly guide ……….p5-p17
3、Structure parts diagram…..p18
4、Repairing guide …………...p19-p29

3
Product introduce

4
Product introduce
Model ：
Product size：134*67*10.25
Platform：MTK6572，dual-core 1GHz
Memory：4GB+4Gb (Nand&sdram+RAM）
System：Android 4.2
Frequency band: WCDMA：2100，GSM：900/1800MHz
Battery：1500mAh
charger: Travel charger
USB cable: MICRO 5PIN
earphone：3.5jack
LCD&TP：4.5 FWVGA, Capacitance TP
Camera：0.3M and 5.0M CMOS
Support：BT2.1，WIFI，FM。
Support：3D graphics accelerator，accelerator sensor, distance sensor, light
feeling sensor。

5
Hot gun
Tweezer
Solder iron
Tommy bar
Cross Screw driver
1. Tools list
Tweezer /Cross screw driver/ Solder/Tommy bar/hot gun
Disassembly guide

6
2. Battery caver disassembly
open the battery cover，as the Fig. 1
Fig. 1
Disassembly guide
Battery
cover

7
3. Back caver disassembly
1）Unscrew 12 screws in back cover ，as the Fig.2；
Fig. 2
Disassembly guide

8
Fig. 3
2）Disassemble back cover with Tommy bar ，as the Fig.3；
Disassembly guide
Back
cover SPK

9
4.Main board and front cover disassembly
1）The main components of distribution，as the fig.4；
Fig.4
Disassembly guide
Main PCBA LCD con.
Front
CAM con.
Back CAM.
USB con.
Earphoe
con.
TP con. T card
con. SIM con. Main FPC
Sub PCBA
vibrator
RF cable
Battery con.

2）remove two screws and open the LCD con.& TP con. ，and remove the
volume key FPC & power key FPC as the fig.5；
10
Fig.5
Disassembly guide
TPcon.
LCDcon.

3）open the main board and remove the RF cable con. And main FPC
con..as the FIG.6
11
Fig.6
Disassembly guide
RF cable con. Main FPC con.
Main board

remove the light sensor and camera，as the fig.7；
12
5. Front and Back camera & light sensor disassembly
Fig.7
Disassembly guide
Back
cam.
Front
cam.
Light sensor&holder
Light sensor con.

13
Fig.9
remove the Speaker camera and receiver，as the FIG.9；
7. Speaker & receiver disassembly
Disassembly guide
receiver

14
Fig.10
8. RF cable and Main FPC disassembly
Remove the RF cable and Main FPC ，as the fig.10
Disassembly guide
RF cable
Main FPC

15
Fig.11
9. Sub PCBA disassembly
remove the sub PCBA from the ，as the fig.11；
Disassembly guide
Sub PCBA
vibrator

16
Fig.12
10.MIC disassembly
Remove the MIC，as the fig.12；
Disassembly guide
MIC con.

17
Structure parts diagram
3in1 module
(LCD, TP & front cover
Back
cover
Battery
cover
Main
PCBA sub PCBA 5M camera
0.3M camera
Main FPC
Light
sensor
Sensor
holder
receiver
SPK
RF cable

18
Repairing guide
1. LCD
a. Check if the SW is correct, otherwise to upgrade the SW;
b. Check the LCD if is ok, otherwise change a new LCD;
c. If that the LCD loose, re-assemble the LCD and test;
d. Checking the LCD connector if is ok, otherwise re-solder it or change a new one;
e. Checking the circuit around the LCD connector.
LCD
connector

19
2. Camera
a. Checking the camera is assemble ok, re-assemble the camera and test;
b. Using the good camera to do cross test, it can check if the camera is ok;
c. Checking the camera connector if is ok as below picture, otherwise to
re-solder or change a new one;
d. Checking the circuit around the camera connector.
Repairing guide
Back Camera
connector Front Camera
connector

20
3. TP
a. Checking the SW and upgrade the SW;
b. Checking the FPC of TP and re-assemble it;
c. Using the good TP to do cross test;
d. Checking the TP connector, otherwise re-solder or change a new one;
e. Checking the circuit around the TP connector.
Repairing guide
TP Connector