Lenovo A680 Service Manual

Lenovo Confidential

A680 SERVICE MANUAL

V1.0

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Lenovo Confidential

Documents statement:

 This document is intended for use by qualified service

personnel only.

 The documents only are used for service reference.

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TABLE OF CONTENT

Section page

1. Product Figures ......................................................................... 5

1-1. Exploded view .................................................................. 5

1-2. Product Main Function ..................................................... 7

1-3. General Specification ....................................................... 8

2. Block Diagrams ......................................................................... 9

2-1. System Diagrams ............................................................. 9

2-1-1 BBIC Diagrams ...................................................... 10

2-2. Power Management Diagrams ....................................... 11

3. Flow Chart of Troubleshooting ................................................ 12

3-1.Baseband ........................................................................ 12

3-1-1. Phone does not start up troubleshooting ............... 12

3-1-2. SIM troubleshooting .............................................. 15

3-1-3. MIC troubleshooting .............................................. 17

3-1-4. T-Flash troubleshooting ........................................ 19

3-1-5. Speaker troubleshooting ....................................... 20

3-1-6. Earpiece troubleshooting ...................................... 21

3-1-7. Vibra troubleshooting ............................................ 22

3-1-8. Camera troubleshooting ........................................ 23

3-1-9. FM radio troubleshooting ...................................... 25

3-1-10. Display troubleshooting ....................................... 27

3-1-11. Bluetooth WIFI GPS troubleshooting .................. 30

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3-1-12. Keyboard troubleshooting ................................... 32

3-1-13. Charge troubleshooting ....................................... 34

3.2 RF ................................................................................... 36

3-2-1.GSM/DCS RX troubleshooting ............................... 36

3-2-2.DCS/GSM TX Part ................................................. 37

4. Main Element Specifications ................................................... 39

4-1 Baseband part ................................................................. 39

4-1-1. BBIC(U401) .......................................................... 39

4-1-2. WIFI/GPS/FM/BT IC(U1101) ................................. 48

4-1-3. Charge IC(Q601) .................................................. 51

4-1-4. NAND+SDRAM(U501) .......................................... 52

4-2. RF part ........................................................................... 56

4-2-1. RF PA(U101) ........................................................ 56

4-2-2. RF TRANSCEIVER (U201) ................................... 59

5. Test Instructions ...................................................................... 65

6. Glossary .................................................................................. 66

7. Warnings and cautions ............................................................ 68

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U101 RF PA

Damage caused by failure：
Call fault

J601 duo electrical
connector

Damage caused by failure：
does not boot; power down;

J1001 /J1002 SIM card

Damage caused by failure：
does not know the SIM card

U601 Power Management

Damage caused by failure：
large currents;does not boot;

X601 32.786 Crystals

Damage caused by failure：
Unbootable

U401 BBIC

Damage caused by failure
does not boo;crashes

U501 NAND SDRAM

Damage caused by failure：
does not boot; showing
white; storage
failures,;software problems

J901 Headphone Jack

Damage caused by failure：
Headphones silent;
not receive FM

U203/U205/U102 RX filter

Damage caused by failure：
Call failed

U201 RF-TR

Damage caused by failure：
Does not boot;
RF faults

X201 26M Crystals

Damage caused by failure：
Can not boot;

J1003 T-flash card

Damage caused by failure：
does not know the T-flash
card;

U1101 MT6627 IC

Damage caused by failure：
WIFI/GPS/FM/BT does not
work

U902 G-sensor IC

Damage caused by failure:
The screen can not be
rotated

J902 USB connector

Damage caused by failure：
Not charging,;
data transfer faults

J801 LCD connector

Damage caused by failure：
Does not display

J803 back camera

Damage caused by failure：
Camera does not work

J802 CTP connector

Damage caused by failure：
No Touch

1. Product Figures

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ITEM

Part No.

Model

QULITY

1

HQ11110038000

MT6627N

1

2

HQ11100182000

MT6582V/X

1

3

HQ11100134000

MT6323GA

1

4

HQ11100133000

MT6166A

1

5

HQ11120059000

KMK5U000VM-B309

1

6

HQ11160067000

SN2145B

1

7

HQ11160064000

sky77590

1

8

HQ11180003000

BMA220

1

J804 front camera

Damage caused by failure：
Camera does not work

Part name

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PCS1900

1850～1910
1930～1990

1-2. Product Main Function

 Support Camera

 Music player

 Support T-Flash card

 Support WIFI

 5.0" FWVGA LCD

 Support GSM900&DCS1800&PCS1900&WCDMA2100

&WCDMA900 Network

 Support bluetooth

 Support FM radio
 Support dual SIM card
 Support G-sensor

 Support GPS

 Support Distance sensor
 Support Torchled

1-3. General Specification

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2. Block Diagrams

2-1. System Diagrams

Remark：FM/GPS/WIFI/BT to Four in Chip;

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2-1-1 BBIC Diagrams

Mediatek MT6582 is based on four core ARM architecture (28 nm A7 architecture,
frequency of 1.3 Ghz, can be seen as MT6572 quad-core upgraded or modified MT6589,
in addition the CPU or the first td-scdma and WCDMA dual-mode integrated in the same
single chip (can be seen as MTK6582 will bring TD baseband chips, the disputed). At the
same time, mediatek will also launch MT6582m MT6582 cheap version. Including
mediatek MT6582 highest level support 720 p resolution screen; Mediatek MT6582M is
the highest level can only support the QHD screen. Frequency is 1.3 Ghz, collocation of
GPU models for SGX still 544.

Typical application diagram is shown in nether figure

Application Diagram of MT6582

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2-2. Power Management Diagrams

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3. Flow Chart of Troubleshooting

3-1.Baseband

3-1-1. Phone does not start up troubleshooting

Power-on Sequence and Protection Logic:

The PMU handles the powering ON and OFF of the handset. There are three
ways to power-on the handset system :

① Push PWRKEY (Pull the PWRKEY pin to the low level)
② RTC module generate PWRBB to wakeup the system
③ Valid charger plug-in (CHRIN voltage is within the valid range)

Pulling PWRKEY low is the typical way to turn on the handset. The Vcore buck
converter will be turned-on first, and then Va/Vio/Vm LDOs turn-on at
the same time. After that, the supplies for the baseband are ready and it will
send the PWRBB signal back to PMU for acknowledgement. To successfully
power-on the handset, PWRKEY should be kept low until PMU receives the
PWRBB from BB. Besides, the system reset ends at the moment when the
Vcore/Va/Vio/Vm are fully turned-on to ensure the correct timing and function.

If the RTC module is scheduled to wakeup the handset at some time, the
PWRBB signal will directly control the PMU. In this case, PWRBB becomes
high at the specific moment and let PMU power-on just like the on-sequence
described above. This is the case named RTC alarm.

Charger plugging-in will also turn on the handset if the charger is a valid
charger. However, if the battery voltage is too low to power-on the handset
(UVLO state), the system won’t be turned-on by any of the three ways. In this
case, charger will charge the battery first and the handset will be
powered-on automatically as long as the battery voltage is high enough.

States of mobile handset and regulator

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Troubleshooting flow chart

Main related component: BBIC(U401) ， NAND+SDRAM(U501), XTAL CRYSTAL

（X201),RF-TR(U201), PMIC（U601）,Power button.

Power ON/OFF and download circuit

 BBIC POWER OUT CIRCUIT

 MINI USB CIRCUIT

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J1201

Check the clock generation circuit

(related to BBIC,X201,U201,U501)

Check the baseband circuit

(related to BBIC,U501,keypadfpc,LCD)

Check the VBAT circuit component

(related to U301,U201,U501,LCD,keypad

Download troubleshooting

Main related component: BBIC(U401)，NAND+SDRAM(U501),RF-TR(U201), XTAL

CRYSTAL（X201）, MINI USB(J902).

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3-1-2. SIM troubleshooting

Troubleshooting flow chart

Main related component: BBIC(U401), SIM connector(J1001,J1002)

SIM CIRCUIT

 SIM1&SIM2

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3-1-3. MIC troubleshooting

Troubleshooting flow chart

Main related component: BBIC(U401),MIC

MIC circuit

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J1003

3-1-4. T-Flash troubleshooting

Troubleshooting flow chart

Main related component: BBIC(U401)，T-FLASH CONNECTOR(J1003).

T-Flash circuit

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3-1-5. Speaker troubleshooting

Speaker circuit

Troubleshooting flow chart

Main related component: BBIC(U401),SPEAKER

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3-1-6. Earpiece troubleshooting

Troubleshooting flow chart

Main related component: BBIC(U401),EARPIECE

Earpiece circuit

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