Micromax Q4202 User manual

Q4202 L2 Service Manual

A) Technical Specifications:

Particular

Remarks

Key Matrix For Flashing

LSK

Chipset

MSM8909

Android Version

Android 6.0

Frequency

1.1GHz

Network Mode

2G/GSM：B 2\3\5\8

3G/WCDMA ：B 1\8

4G/FDD：B3\5\40

Rom

8GB

RAM

1GB

Internal SD Card memory

MB can support up 32GB T card

Expandable Memory

MB can support up 32GB T card

Factory mode code

*#86428#

Good Earpiece volume

32 Ω±15%

Good Loudspeaker volume

8Ω±15%

Good MIC volume

2 Ω±15%

Good Vibrator volume

58Ω

Q4202 L2 Service Manual

Engineering Code

B) 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.

C) SERVICE DETAILS

D) SYMPTOMS :

1. Does not power on

LCD+TP

Earphone

connector

Vibrate

I/O

Front

camera

Main

camera

SIM

connector

Antenna

Batt

ery

conn

ector

GSM

Antenna

BWG

ANT

FJ ANT

Q4202 L2 Service Manual

NO.

Description

Reason

Solution

NO Power On

Software issue

Update Software

Battery capacity level is too low

Charging the Battery

Power On Key is fail

Change Key

Main PCBA issue

Refer to the L3 maintenance manuals or

change PCBA

2：Display issue/No display

NO.

Description

Reason

Solution

LCD+TP

Software issue

Update Software

LCD fail\ TP connection

issue

Change LCD

LCD backlight circuit issue

Refer to the L3 maintenance manuals or Change

PCBA

Side Key FPC

soldering

Power Key

Battery

connector

LCD connector

Q4202 L2 Service Manual

3：Proximity Sensor not working

Description

Reason

Solution

Proximity

sensor

Software issue

Download software

Sensor holder is not assembled well

Re-assemble the sensor holder

PCBA fail

Change PCBA/Refer to L3 repair

Inspect the sensor. If it is broken, change with a new one.

4：G-sensor not working

Description

Reason

Solution

Proximity

sensor

Software issue

Download software

Sensor holder is not assembled well

Re-assemble the sensor holder

PCBA fail

Change PCBA/Refer to L3 repair

5：Keys not working

NO.

Description

Reason

Solution

P- sensor

G- sensor

Q4202 L2 Service Manual

Key is not work

Key fail

Change Key

Key is not assembled well

Re-assemble

PCBA issue

Change PCBA/Refer to L3 repair

6：Charging issue

NO.

Description

Reason

Solution

Cannot charge

Adapter fail

Change adapter

Have charging icon,

But not charged

Battery fail or Battery

connect fail

Change battery or Change battery connect

FPC fail or FPC connect

fail

Change FPC or FPC connect

PCBA fail

Change PCBA/Refer to L3 repair

7：USB port issue

NO.

Description

Reason

Solution

Cannot connect

to PC

Data cable is fail

Change data cable

USB connect fail

Change USB connect

Side Key FPC

soldering

Side Key FPC

USB connector

Battery connector

FPC

Q4202 L2 Service Manual

FPC fail or FPC

connect fail

Change FPC or FPC connect

Main PCBA issue

Change main PCBA/Refer to L3 repair

8：Front Camera not working

NO.

Description

Reason

Solution

Colored screen when open

front camera

Camera issue

Change camera

Camera connect fail

Change camera connect

PCBA issue

Change PCBA/Refer to L3 repair

Cannot turn on front camera

Camera issue

Change camera

Camera connect fail

Change camera connect

PCBA issue

Change PCBA/Refer to L3 repair

9：Rear Camera not working

NO.

Description

Reason

Solution

Colored screen when open

front camera

Camera issue

Change camera

Camera connect fail

Change camera connect

PCBA issue

Change PCBA/Refer to L3 repair

Cannot turn on front

camera

Camera issue

Change camera

Camera connect fail

Change camera connect

PCBA issue

Change PCBA/Refer to L3 repair

USB connector

Front camera connector

FPC

Battery connector

Q4202 L2 Service Manual

10：Error Playing Video

NO.

Description

Reason

Solution

Flash Light

Software issue

Update Software

Flash light fail

Change flash light

PCBA fail

Change PCBA/Refer to L3 repair

11：Vibrator not working

NO.

Description

Reason

Solution

Vibrator

Setting issue

Open the vibration function

Soldering issue

Re-soldering vibrator

Soldering issue

Re-soldering Main FPC

Rear camera connector

Flash Light

drive IC

Flash Light

Q4202 L2 Service Manual

Main FPC connect fail

Change Main FPC connect

Moto issue

Change Moto

Main FPC fail

Change Main FPC

Main PCBA issue

Change main PCBA/Refer to L3 repair

12：WiFi/BT /GPS not working

NO.

Description

Reason

Solution

Software issue

Update software

antenna fail

Change antenna

PCBA issue

Change PCBA/Refer to L3 repair

13：RF (SIM) Network issue

NO.

Description

Reason

Solution

4G can not

4G did not open

Open the 4G

Main FPC connect

Vibrator soldering

Antenna

connector

Q4202 L2 Service Manual

searchable

Software issue

Update software

34G antenna is fail

Change 4G antenna

RF cable connect issue

Reassemble the RF cable connect

RF Cable fail

Change RF Cable

SUB PCBA issue

Change SUB PCBA

PCBA fail

Change PCBA/Refer to L3 repair

14：FM not working

NO.

Description

Reason

Solution

FM is not working

Software issue

Update software

Earphone issue

Change earphone

Earphone connect fail

Change earphone connect

PCBA fail

Change PCBA/Refer to L3 repair

15: Receiver not working

RF cable

connector

Antenna

connector

Ear phone connector

Q4202 L2 Service Manual

NO.

Description

Reason

Solution

Receiver

The volume to shut down

Press V +, transferred to the suitable volume

Dust with receiver

Clean receiver

Receiver issue

Change receiver

Volume key issue

Change volume key

PCBA issue

Change PCBA/Refer to L3 repair

16：Earphone not working

NO.

Description

Reason

Solution

Single output

from earphone

Earphone issue

Change earphone

Earphone jack smudges

Clean up the earphone jack

Earphone jack pin is weld weak

Strong weld the jack pin

Earphone jack is fail

Change earphone jack

Main PCBA fail

Change main PCBA/Refer to L3 repair

17：MIC not working

NO.

Description

Reason

Solution

Mic

Setting issue

Open the vibration function

Soldering issue

Re-soldering Mic

Soldering issue

Re-soldering Main FPC

Main FPC connect fail

Change Main FPC connect

Receiver connector

Ear phone connector

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