cromax A121 User manual

A121 L2 Service Manual
Product introduce
Model ：A121
Product size：146.2*74.2*10.2mm
Platform：MSM8212，1.2GHz Quad
Memory：4GB+1GB (Nand&sdram+RAM）
System：Android
Frequency band: WCDMA：900+2100 ，GSM：850/900/1800/1900
Battery：2000mAh
Charger: Travel charger
USB cable: MICRO 5PIN
Earphone：3.5jack
LCD&TP：5.0HD IPS, resolution: 1280*720，Capacitance TP
Camera：2.0M and 8.0M CMOS
Support：GPS，BT4.0，WIFI，WAPI
Support：3D graphics accelerator，accelerator sensor, distance sensor, light
feeling sensor，Double MIC noise reduction
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A121 L2 Service Manual
1. Tools list
Tweezer
Cross screw driver
Solder
Tommy bar
Hot gun
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A121 L2 Service Manual
2. Battery cover disassembly
Open the battery cover，as the Fig. 1
3. Back caver disassembly
Unscrew 9 screws in back cover，as the Fig.2
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A121 L2 Service Manual
Disassemble back cover with Tommy bar，as the Fig.3
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A121 L2 Service Manual
4. Main board and front cover disassembly
The main components of distribution，as the fig.4
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A121 L2 Service Manual
Remove 3 screws and open the LCD con. & TP con，remove the volume key
FPC & power key FPC, as the FIG. 5
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A121 L2 Service Manual
Open the main board and remove the RF cable con. And main FPC con..as
the FIG.6
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A121 L2 Service Manual
5. Camera & light sensor disassembly
Remove the light sensor and Front camera and Back camera，as the fig.7
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A121 L2 Service Manual
6. Power key FPC & volume key FPC disassembly
Remove the power key FPC and volume key FPC with the iron，as the fig.8
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A121 L2 Service Manual
7. Sub PCBA disassembly
Remove the sub PCBA from the, as the fig.9
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A121 L2 Service Manual
8. Receiver, speaker, Main MIC and Back MIC Rubber disassembly, as the
FIG.10
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A121 L2 Service Manual
9. RF cable, Main FPC and vibrator disassembly
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A121 L2 Service Manual
10. Structure parts diagram
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A121 L2 Service Manual
11. Structure parts diagram
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A121 L2 Service Manual
Repairing guide
1. LCD
Check if the SW is correct, otherwise to upgrade the SW;
Check the LCD if is ok, otherwise change a new LCD;
If that the LCD loose, re-assemble the LCD and test;
Checking the LCD connector if is ok, otherwise re-solder it or change a new
one;
Checking the circuit around the LCD connector.
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A121 L2 Service Manual
2. Camera
Checking the camera is assemble ok, re-assemble the camera and test;
Using the good camera to do cross test, it can check if the camera is ok;
Checking the camera connector if is ok as below picture, otherwise to
re-solder or change a new one;
Checking the circuit around the camera connector
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A121 L2 Service Manual
3. Touch Pannel
Checking the SW and upgrade the SW;
Checking the FPC of TP and re-assemble it;
Using the good TP to do cross test;
Checking the TP connector, otherwise re-solder or change a new one;
Checking the circuit around the TP connector.
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A121 L2 Service Manual
4. Ringer
Checking the shrapnel of speaker if is ok;
Checking the resistance of speaker if is ok, otherwise to change a new one;
Checking the FPC if is ok;
Checking SPK-FPC if connector with sub-board is ok.
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A121 L2 Service Manual
5. Reciever
Checking the shrapnel of receiver if is ok;
Checking the resistance of receiver if is ok, otherwise to change a new one;
Checking the connector point on the main board if is ok, as below picture;
Checking the receiver circuit if is ok.
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A121 L2 Service Manual
6. MIC and Vibrator
Checking the MIC and Vibrator is cold soldering, re-solder it;
Change the MIC and Vibrator;
Checking the circuit of MIC and Vibrator;
Checking the FPC if connect ok.
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