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

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4.2 Camera defects
4.2.1 Rearcameradefects
OK
Check to see whether the EMI
device is complete and welding is
in good condition; if not; repair
EMI device(Z1701—Z1705)
Recheck after replacing front
camera
Check to see whether
the front camera is
abnormal
N
Y
N
N
Recheck after overlaying welding
Y
N
Whether the camera is OK
after replacing the camera
module
Check to see whether the camera
module connector is welded well;
whether the camera is OK after
overlaying welding the connector?
N
YOK
Check to see whether the camera
module is in the right position by
disassembling and whether the module
is OK after reassembling module
N
Y
OK
Check to see whether the main
chip U401 are normally
welded?
Re-weld or replace U401
N
Can not take photos

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4.3 Ring and vibration
4.3.1 Novibration
Replace the motor to see whether
it is ok? Check to see whether the
circuit around the motor is
normal
(
R1808，C1811
)
OK
Y
N
Check whether the motor is interfered by
structure; Recheck whether it is normal after
reassembling the phone.
OK
Y
No vibration
N
Replace U503 chip
N

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4.3.2 Noring
Check to see whether the main chip U503 is
damaged. Replace it if damaged.
N
N
Replace Speaker and recheck whether it is
normal?
Check to see whether the SPK circuit is
normal?(D1405,D1406,C1413,B1405,B1406,R
505,R506)
Use earphone to test whether there is sound; if
there is sound from earphone, there is audio
signal to input. Check whether J1803 KB
connector device is of cold solder joint; recheck
whether it is ok after re-welding，Replace the
KB connector FPC to try again
；
OK
OK
OK
Y
Y
Y
No ring

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4.4 Charging
4.4.1 Nochargingdisplayafterpluggingthechargerin
Check whether the charging is normal
after replacing the charger (J801). Replace the charger
No charging display after
plugging the charger in
N
Y
Replace the battery and see whether the
charging is normal? Measure the battery
volta
g
e to see whether it is less than 3V
Replace the battery
Y
N
Check to see whether U630 module
device is well welded? Whether it is
normal after re-welding
Y
OK
N
Replace U503 YOK

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4.4.2 Chargingshownbutnotfullcharging
Check to see the Voltage of VCHG is
normal (5.0V), Check the VCDT Circuit
& ISENSE Circuit components is normal
(R523, R524, R551, R571,R663,R662 )
Replace U630 module device and
then recheck
Re
p
lace U503
Replace the battery and then check whether it
is fully charged
Charging shown but not
full charging
OK
Y
N
N
N
OK
Y
OK
Y
Re-solder the USB connector
or change for another FPC ;
Re-solder or change the
components which is damaged
or in poor soldering
Y

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4.5 Keyboard and keyboard backlight
4.5.1 Abnormaloperationofsidekeys
N
Abnormal side key
Re
p
lace U401/U503
Check whether there are conditions like cold
solder joint and short circuit on keyboard
FPC ? Whether it is ok after re-welding?
Check whether there are conditions like cold solder
joint and missing device on the circuit device of side
keys and power key .
( R1806,R1807,D1802,D1803,R1801,D1801,C1801 )
Y
O
K
N
OK
YOK
FPC is fracted, Replace
side keys FPC
N

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4.5.2 AbnormaloperationofCTPkeyboard
CTP keyboard is invalid
Whether the CTP test is normal?
It is the problem of CTP connector J1601
or main chip U401 welding
CTP damaged,
replace it
Y
Replace CTP
Y
N
N
Replace one CTP to see whether
it is the problem of touch screen
or main board?

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4.6 Calling
4.6.1 Novoiceheardfromtheothersideduringthecall
No voice heard from the other
side durin
g
the call
Replace the headphones and then re
check whether it is normal
N
Y
OK
N
Replace U503
Check whether
B1403,B1404,C1428,C1427,D1403,D140
4,are well welded. Re-weld and test
Use earphone and hands-free to verify
whether there is voice?
N Cold solder joint
of main
chip(U503) or
main chip(U503)
is abnormal
Y Y OK

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4.6.2 Novoiceheardfromyoursideduringthecall
Re-weld
Check U503 and
C1402,C1403,R1401,R1402,R1403R1404 is OK
N
No voice heard from your side during the call
Check whether receiver and the peripheral devices are
well welded; whether it is ok after re-welding?
Y
Check whether receiver module device is well
welded. Replace this device and see whether it is
ok? OK
N
Y

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4.7 Power-on failure
Failed to Power-on
Check whether the 26MHz on X801
is normal? Whether there is 26MHz
signal
Check whether X801 is well
welded
Y
N Re-weld and recheck
Re-weld and recheck
N
Replace the main chip U503
Y
Power on the phone on separate main
board , whether there is high current?
N
YThe main board is damaged;
replace the main board and check
the failure board step by step
Check whether the power key FPC is
assembled well , reassembling the
p
ower FPC ?
N
YRe-weld
Y
Check whether the main power supply of U503 is
normal?
（VCORE,VPROC,VIO18,VTCXO,VIO28,VRF
28,VRF18,VMC, etc.）
NRe-weld or
replace device
U301 to recheck