Lenovo P70-A User manual

Service Manual of
Lenovo P70-A Mobile
Phone
Lenovo

Repair Manual of Lenovo P70-A Mobile Phone
1
Document name Service Manual of Lenovo P70-A Mobile Phone
Version: V1.0
Date: Nov 3, 2014
Document No.:
Status:
Preface
This manual is intended for online repair guidance and after-sale repair guidance of
Lenovo P70-A mobile phone produced by the Company
The content of this manual will be upgraded according to the needs of technology
development.
Copyright
The copyright of this manual belongs to Lenovo Mobile; anyone who reproduces this
manual without written consent of the Company shall bear legal responsibility.

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Content
1.Appearance.............................................................................................................................5
2.Layout of main board.............................................................................................................6
3.Baseband.................................................................................................................................7
4.Main adverse analysis...............................................................................................................8
4.1LCD DISPLAY ...........................................................................................................................8
4.1.1No display on screen after power-on...................................................................................8
4.1.2LCD backlight without lighting ...........................................................................................9
4.2CAMERA DEFECTS...................................................................................................................10
4.2.1Rear camera defects ..........................................................................................................10
4.3RING AND VIBRATION..............................................................................................................11
4.3.1No vibration.......................................................................................................................11
4.3.2No ring...............................................................................................................................12
4.4CHARGING..............................................................................................................................13
4.4.1No charging display after plugging the charger in............................................................13
4.4.2Charging shown but not full charging ...............................................................................14
4.5KEYBOARD AND KEYBOARD BACKLIGHT................................................................................15
4.5.1Abnormal operation of side keys .......................................................................................15
4.5.2Abnormal operation of CTP keyboard...............................................................................16
4.6CALLING.................................................................................................................................17
4.6.1No voice heard from the other side during the call............................................................17
4.6.2No voice heard from your side during the call...................................................................18
4.7POWER-ON FAILURE................................................................................................................19
4.8LCD ON WHEN CLOSE TO THE EAR DURING THE CALL;LCD OFF WHEN AWAY FROM THE EAR.20
4.9RADIO FREQUENCY (RF).........................................................................................................21
4.10SOFTWARE DOWNLOAD FAILURE............................................................................................21
4.11PRODUCTION CALIBRATION ....................................................................................................22
4.11.1AFC calibration.............................................................................................................22
4.11.2AGC...............................................................................................................................23
4.11.3APC ...............................................................................................................................24
4.12FAULT IN COMPLETE SET TEST/REWORK .................................................................................26
4.12.1Switch spectrum & PVT template with excessive standard ...........................................26
4.12.2High Frequency Error ...................................................................................................27
4.12.3High Phase Error ..........................................................................................................27
4.12.4Power output problems..................................................................................................28
4.133G/4G FORECAST ...................................................................................................................29
4.13.1RSSI _Cal ......................................................................................................................29
4.13.2TPC _ Cal......................................................................................................................29
4.143G/4G COMPREHENSIVE TEST.................................................................................................31
4.14.1ACLR or SEM................................................................................................................31
4.14.2ILPC comprehensive test abnormal...............................................................................31

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4.14.3Frequency Err................................................................................................................31
5.Disassembly Guide..............................................................................................................32
6.Assemble Guide...................................................................................................................40

Version
No. Prepared by/ Modified by
Prepared/
Modified
on
Reason for
change Main changes

1. Appearance

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2. Layout of main board
Front of main board:
Back of main board:

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3. Baseband
Block diagram of hardware system

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4.Main adverse analysis
4.1 LCD display
4.1.1 Nodisplayonscreenafterpower‐on
White screen or blank screen without display; backlight
with lighting
Check whether the EMI device Z1601--Z1605 of
LCD circuit on main board is solder incompletely;
re-solder EMI device
OK
Check whether there is cold solder joint on other
device around LCD and on LCD connector.
Check the connection of LCD FPC is good and
re-assembled FPC whether phone is normal
N
N
Y
OK
Y
Check the display is normal after replacing LCD,
N
OK
Y

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4.1.2 LCDbacklightwithoutlighting
Check whether there are voltages more than
24V between both ends of C1612 when LCD
is lit.
OK
If the backlight circuit is
normal, it is the problem
of LCD
Check the welding condition of U1603 and
peripheral devices, including L1601,
D1601, C1612,C1611，R1605,R1606
Y
N
Y
YOK
Check whether the connection of FPC on
LCD module and connector on main board is
good and whether the LCD backlight is
normal after reconnection
N
Re-verify whether the LCD backlight is
normal after replacing LCD. OK
Y
N
LCD backlight without lighting