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Repair Manual of Lenovo P70-A Mobile Phone

4.14

3G/4G comprehensive test

4.14.1

ACLR

SEM

Fault: ACLR or SEM

Cause: No calibration or PA

（

U901,U902

）

is in cold solder joint; check the Point problem circuit

components or RF transceiver (U801) doesn’t work well.

Repair manner:

4.14.2

ILPC

comprehensive

test

abnormal

Fault: ILPC

Cause: No calibration or just passing calibration.

Repair manner: The same as 4.5.1.

4.14.3

Frequency

Err

Fault: Frequency Err

Cause: No calibration, or suffered outside interference

Repair manner: Recalibrate 3G/4G and test; replace X801.

ACLR or SEM

Whether it is OK after recalibrating WCDMA/LTE?

Re-weld PA or replace PA and the devices in

transmission circuit?

Re-weld or replace

transceiver

Summary of Contents for P70-A

Page 1: ...Service Manual of Lenovo P70 A Mobile Phone Lenovo ...

Page 2: ...ended 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 ...

Page 3: ...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 1...

Page 4: ...Repair Manual of Lenovo P70 A Mobile Phone 3 4 14 3 Frequency Err 31 5 Disassembly Guide 32 6 Assemble Guide 40 ...

Page 5: ...Version No Prepared by Modified by Prepared Modified on Reason for change Main changes ...

Page 6: ...1 Appearance ...

Page 7: ...Repair Manual of Lenovo P70 A Mobile Phone 6 2 Layout of main board Front of main board Back of main board ...

Page 8: ...Repair Manual of Lenovo P70 A Mobile Phone 7 3 Baseband Block diagram of hardware system ...

Page 9: ...klight 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 ...

Page 10: ...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 Y OK 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 lighti...

Page 11: ...normal 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 Y OK 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 se...

Page 12: ...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 ...

Page 13: ... 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 ...

Page 14: ...placing 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 voltage 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 Y OK ...

Page 15: ...E Circuit components is normal R523 R524 R551 R571 R663 R662 Replace U630 module device and then recheck Replace 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 ...

Page 16: ... 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 OK N OK Y OK FPC is fracted Replace side keys FPC N ...

Page 17: ...ration 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 ...

Page 18: ... the other side during 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 ...

Page 19: ...heck 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 ...

Page 20: ... N Replace the main chip U503 Y Power on the phone on separate main board whether there is high current N Y The 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 power FPC N Y Re weld Y Check whether the main power supply of U503 is normal VCORE VPROC VIO18 VTCXO VIO28 VRF 28 VRF18 VMC etc N Re w...

Page 21: ...D during the call Check whether P Sensor related circuit is normal Or replace p sensor IC U1502 Replace the application of gum of touch screen and re paste Y p sensor FPC Problem Y Check whether G SENSOR and touch screen is normal If G SENSOR and touch screen is normal I2C is normal or else U401 is abnormal Whether the touch screen is well pasted with the shell N ...

Page 22: ... cold solder joint Shooting Re download software when it is normal after replacing elements Check whether TCXO X801 is oppositely pasted Software can t be normally downloaded or the phone can t Power on be turned on Re weld USB connector or use another KB to verify it Y N Re weld X801 N Y N Whether flash U701 is oppositely pasted Check whether USB connector is in cold solder joint Re weld U401 Y W...

Page 23: ...ld X801 Check whether there is MT6166 U801 4 11 Production calibration 4 11 1 AFC calibration Fault AFC calibration Fail Reason RF test cable is not connected well during calibration TCXO is oppositely pasted or in cold solder joint Shooting Notes Remember to recalibrate after replacing elements AFC calibration Fail Reconnect and calibrate N Y N Re weld X201 Y N Y Recalibrate N Replace PA U801 Y ...

Page 24: ...ther X801 is in cold solder joint Re weld Re weld or replace Whether Rx is in cold solder joint Re weld Re weld Whether C809 are in cold solder joint Whether U801 Rx is in cold solder joint Check the baseband chip U401 Re weld Re weld or replace 4 11 2 AGC Fault AGC calibration Fail Reason RF test cable is not connected well during calibration the devices in receiving cable are in cold solder join...

Page 25: ...e and fixtures are well connected Reconnect and calibrate 2G 3G frequency fails LTE frequency fail Replace components PA input circuit are welded with disconnection Whether PA is in cold solder joint Replace PA 4 11 3 APC Fault 1 Fault APC calibration Fail Cause RF test cable is not connected well during calibration PA is oppositely pasted PA and peripheral circuit are in cold solder joint The pat...

Page 26: ... high Cause The cable isn t well connected in calibration Shooting Fault 3 Fault After repeated calibration the power is still low Cause Some element patches of PA and surrounding VAPC input are displaced or PA is damaged Shooting After repeated calibration the power is still low Related PA may be partially damaged recalibrate Replace Vramp circuit N Calibration power is too high ...

Page 27: ...ency bands are excessive Cause The cold solder joint or damage to components in V_ramp of PV may result in the excessive switch spectrum Shooting Measure to see whether the voltage of PA is in the normal range 1 8V or less Switch spectrum and Ramp Mask with excessive standard Check whether the input and output matching is in cold solder joint Replace the elements in cold solder joint Replace PA if...

Page 28: ...cuit of TCXO Shooting 4 12 3 High Phase Error Fault Phase Error exceeds standard in complete set test Cause The capacitors of power supply part of PA and transceiver are in cold solder joint or in short circuit with other resistance Shooting Excessive Frequency Error Check whether X801 is in cold solder joint or damaged Replace the elements in cold solder joint Recalibrate ...

Page 29: ...atch RF power amplifier PA A Whether the control signal of PA U901 U902 is high level about 2 8V if it is low level there is no output of PA B Check the PA power supply part to see whether the power supply voltage is in the normal range typically 3 6V 4 2V C Whether the RF input parts of PA are in cold solder joint D Whether the RF output parts of PA is in cold solder joint E Part circuit of VPA_P...

Page 30: ...0dBm output power can be detected on the output end of RF connector B About 3dBm output power can be detected on matching circuit parts of PA input end C About 32dBm or 29dBm output power can be respectively detected on pinD11 connection of PA output end D About 3dBm output power can be detected on Transceiver U801 output end 4 13 3G 4G forecast 4 13 1 RSSI _Cal Fault RSSI fails Cause There are pr...

Page 31: ...ector J1001 Tx module U901 and the surrounding circuit devices are in cold solder joint Whether 3G 4G PA U901 U902 is oppositely pasted or in cold solder joint N N N Whether the duplexer U1001 through which 3G 4G transmission channel passes is in cold solder joint Reconnect and calibration Re weld Re weld Y Y Y Re weld Y ...

Page 32: ...ll Repair manner 4 14 2 ILPC comprehensive test abnormal Fault ILPC Cause No calibration or just passing calibration Repair manner The same as 4 5 1 4 14 3 Frequency Err Fault Frequency Err Cause No calibration or suffered outside interference Repair manner Recalibrate 3G 4G and test replace X801 ACLR or SEM Whether it is OK after recalibrating WCDMA LTE Re weld PA or replace PA and the devices in...

Page 33: ...enovo P70 A Mobile Phone 32 5 Disassembly Guide 1 Remove the battery cover Divides the battery cover is separated from B shell from your mobile phone at the bottom right hand as shown in figure 1 and 2 Figure 1 Figure 2 ...

Page 34: ...driver to take out the 8 screws 8 red circle marked as shown in figure 3 Figure 3 3 Remove the B shell Break open outward the top right corner to B shell According to the order 1 4 of the figure 4 in turn to open B shell Or use A teardown piece is separated from A shell Figure 4 ...

Page 35: ...e red circle marked two screws of antenna pedestal Figure 5 4 Separate the A shell and PCB mainboard LCD motor TP side key camera battery FPC Open the CTP LCD s FPC cover then pull out the FPC Then separate the A shell of the joint surface and side key camera battery FPC moto as shown in figure 6 Figure 6 ...

Page 36: ...a bracket on mall plate then remove the battery and the main board and small plate connection coaxial line Use the screwdriver loosen three screws shown as the figure 7 8 9 from A shell motherboard Loosen screws from small plate also will be motherboard cock as a whole Figure 7 Figure 8 ...

Page 37: ...Repair Manual of Lenovo P70 A Mobile Phone 36 Figure 9 ...

Page 38: ...ed the TP temperature at 80 for 10 minutes with suction cups on the TP from A shell will be removed Notice First from the right side of the TP split up in central with teardown card along the clockwise direction TP is separated from A shell In separate to the top when should pay attention to protect the FPC slow down to action avoid the FPC is torn After the TP removed use film to protective the L...

Page 39: ...air Manual of Lenovo P70 A Mobile Phone 38 Figure 12 Figure 13 8 Remove the motor camera FPC side key Use the soldering iron to remove the motor wire side key FPC from the motherboard as shown in figure 14 ...

Page 40: ...Repair Manual of Lenovo P70 A Mobile Phone 39 Figure 14 ...

Page 41: ... of Lenovo P70 A Mobile Phone 40 9 The motor camera side key FPC samples as shown in the figure 15 Figure 15 6 Assemble Guide Please refer to disassembly Guide assembly process in contrary to the disassemble process ...

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