Micromax Q427+ Service Manual

Q427+ L2 Service Manual

Particular

Remarks

Key Matrix For Flashing

NA

Chipset

MT6735P

Android Version

Android 6.0

Frequency

1.3GHz

Network Mode
2G: 850MHz/900MHz/1800MHz/1900MHz

3G: B1 B8

Data Segment

GPRS, EDGE, HSPA+ 21Mbps, FDD-LTE, TDD-LTE

Rom

16G

RAM

2G

Internal SD Card memory

12G

Expandable Memory

64G

Factory mode code

Press vol+/ Vol-/ power key at the same time

Good Earpiece volume

32Ω± 15%

Good Loudspeaker volume

8Ω± 5%

Good Mic volume

2.2kΩ± 5%

Good Vibrator volume

30Ω± 5%

1：Technical Specifications

Q427+ L2 Service Manual

Main
camera

Earphone
connector

Vibrator

Charge
connector

Front
camera

SIM
connector

TP
Connetor

SIM
connector

Battery
connector

RF coaxial
line

RF
Antenna

Main
FPC

LCD
connector

GPS
ANT

SPK
RF ANT

T-Flash
connecto

Volume
key FPC

Battery

Wifi /BT
ANT

Fingerprint
FPC

2：CAUTIONS

I. Flashing & Servicing must be undertaken by qualified personnel only.

II. Ensure all work is carried out at an anti-static workstation and that an anti-static wrist strap is worn.

III. Use only approved Tools & components as specified in the parts list.

IV. Ensure all components, modules, screws, and insulators are correctly re-fitted after servicing and

alignment

V. Ensure all cables and wires are repositioned correctly if Handset disassembled

VI. Electrostatic discharge can easily damage the sensitive components of electronic products.

Therefore, Service Centre must adhere the precautions which mentioned above.

3、service Details

Q427+ L2 Service Manual

S.NO

Possible Cause

Validation steps

Action

1

Shorting

Check shorting with Multi meter

Replace PCB if found
faulty

2

Battery

a) Clean the 3 or 4 golden color

point(its terminals)on the battery

b) Check voltage with Multi meter

Value must be 3.7V DC or above

Replace if found faulty

3

Battery

Connector

a) Check battery connector
b) Keep Multi meter on 20V DC and

check value must be 1.5 to 3.5V DC

Re-solder/Replace if
found faulty

4

SW failure

Flashing with latest software

Flashing

5

Power on Key

Key failure

Re-solder/Replace if
found faulty

6

PCB

Suspected PCB faulty

Refer L3 repair

Side Key

Battery
connector

1. Does not power on

Q427+ L2 Service Manual

S.NO

Possible Cause

Validation steps

Action

1

No display

SW issue

Flash the handset with latest SW

LCD issue

Re-assembly LCD/Replace it

PCBA issue

Re-assembly PCBA/Replace it

PCBA issue

Re-Solder the LCD connector or change it

2

Colored screen

LCD issue

Re-assembly LCD/Replace it

3

Dark screen

LCD issue

Re-assembly LCD/Replace it

SW issue

Flash the handset with latest SW

LCD backlight circuit issue

Refer L3 repair

LCD backlight is set

too low by person

Reset the value of backlight

LCD
connector

LCD

2：Display issue/No display

Q427+ L2 Service Manual

S.NO

Possible Cause

Validation steps

Action

1

TP not working

SW Issue

Flash the handset with latest SW

TP issue

Re-assembly TP/Replace it

PCBA issue

Refer to L3 repair

PCBA issue

Re-Solder the TP connector or change it

2

TP not working proper
TP issue

Re-assembly TP/Replace it

PCBA issue

Refer to L3 repair

TP

TP

3：Touch panel

Q427+ L2 Service Manual

S.NO

Possible Cause

Validation steps

Action

1

Proximity sensor fail

SW Issue

Flash the handset with latest SW

Sensor holder is not
assembled well

Re-assemble the sensor holder
PCBA issue

Change PCBA

S.NO

Possible Cause

Validation steps

Action

1

G-sensor is not working

SW Issue

Flash the handset with latest SW

Set problem

Reset mobile

PCBA issue

Change PCBA

Proximity
sensor

G-sensor

4：Proximity Sensor

5：G-sensor