cromax x249 User manual

X249 L2 Service Manual
1. Technical Specifications
Below given remarks are for reference only.
Particular
Remarks
Key Matrix For Flashing
N/A
Chipset
MT6260D
Android Version
N/A
Frequency
360Mhz
Network Mode
GSM 900/1800
ROM
24Mb
RAM
32Mb
Internal SD Card memory
NO
Expandable Memory
32GB
Factory mode code
*#510838#
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.

X249 L2 Service Manual
3. L2 Level trouble shooting
3.1 Structural Parts Fault
3.2 Fail to Start Up
3.3 No Ringtone
3.4 LCD Abnormal Display
3.5 Charging Abnormal
3.6 Fail to Identify SIM
3.7 No Echo, Fail to Record (But There Has Ring Tone)
3.8 Keypad Fault
3.9 Receiver Fault
3.10 Earphone Radio Silent
3.11 ExternalAudio radio Silent
3.12 No Signal
3.13 Fail to Recognize T-Flash Card
3.14 Earphone Fault
3.15 Camera ShootingAbnormalities

X249 L2 Service Manual
3.1 Structural Parts Fault
Replace structural parts by referring to mobile phone disassembly steps.
3.2 Fail to Start Up
YES
YES
NO
NO YES
YES
NO
YES
NO
YES
NO
YES
check battery installed correctly
& battery voltage >3.4v?
re-install & recharge
check the connection between LCD
module and PCBAis reliable（cable
and LCD，cable with PCBA）
and LCD，cable with PCBA）
reassemble
replace LCD and make bad marks
re-download
normally download, keep
parameter when download
replace PCB
make bad mark on the bad PCBA
referring to PCBA Repair Instructions
OK
replace non-defective LCD
module to make sure if normal
fail to start up

X249 L2 Service Manual
3.3 No Ringtone
YES
YES
NO
NO
No
YES
NO
YES
NO
check solder of speaker is
ok?
repair welding of speaker
replace speaker
check if the speaker
circuit is normal
replace speaker
OK
amend the mainboard referring to
its repair instructions
replace the
mainboard
no ring tone

X249 L2 Service Manual
3.4 LCD Abnormal Display
YES
YES
NO
NO
YES
NO
No YES
NO
LCD abnormal display
check if the LED is damaged
replace LCD
analyze the circuit according to the
mainboard to make sure if it is the
mainboard problem
replace the mainboard
OK
amend the mainboard referring to its
repair instructions
check if LCD’s welding
part is pseudo welding
weld LCD and TP’s welding parts

X249 L2 Service Manual
3.5 Charging Fault
YES
YES
NO
NO
YES
NO
NO
check again by replacing battery
or charger
replace battery or charger
weld connector
repair the mainboard
check if the battery and charger
connector is soldering or missing
charging fault
OK
refer to the mainboard repair instructions
replace the main board

X249 L2 Service Manual
3.6 Fail to Identify SIM Card
YES
YES
NO
YES
NO
YES
NO
replace SIM card
check if SIM
connector is
soldering
weld SIM connector
check the periphery circuit of
SIM connector is normal
repair the mainboard by referring to
the mainboard repair instructions
check the connective way of
SIM card or replace SIM card
fail to identify SIM card
OK
replace the mainboard

X249 L2 Service Manual
3.7 No Echo, Fail to Record (But There Has Ringtone)
YES
YES
NO
YES
NO
Yes YES
NO
YES
NO
check MIC for soldering
defect
solder or replace MIC
replace the mainboard
no echo, fail to record (but there has ring tone)
check if MIC sound
hole is jammed
replace MIC and make bad
marks on the bad MIC
OK
replace MIC
clean MIC sound hole
check the periphery circuit of
MIC connector is normal
repair the mainboard by referring to
the mainboard repair instructions

X249 L2 Service Manual
3.8 Keypad Fault
YES
NO
NO
NO
YES
NO
YES
NO
YES
NO
check if the keypad is
assembled correctly
reassemble the keypad
re-paste the DOME
Is structural parts related to
DOME?
amend the related structural parts
check DOME is pasted correctly
keypad Fault
OK
analyze the circuit of the
mainboard keypad part
repair the mainboard by referring to
the mainboard repair instructions
replace the mainboard

X249 L2 Service Manual
3.9 Receiver Fault
YES
YES
NO
YES
NO
NO
YES
NO
NO
weld the pseudo-welding part
replace the mainboard
check if receiver is pseudo
welding
no voice in receiver
OK
replace the receiver
replace receiver
check the periphery circuit
of MIC connector is normal
repair the mainboard by referring to
the mainboard repair instructions

X249 L2 Service Manual
3.10 Earphone Radio Silent
YES
YES
NO
YES
NO
YES
NO
YES
NO
repair or replace the earphone
replace the mainboard
check if the earphone is
damaged
earphone radio silent
OK
check the pin of USB
port is soldering
solder the USB port
check the radio circuit
clean the matter
check if there is some
matter in the earphone
interface
repair the mainboard by referring to
the mainboard repair instructions

X249 L2 Service Manual
3.11 External Audio Radio Silent
YES
YES
NO
YES
NO
YES
NO
replace the speaker
replace the mainboard
check if the speaker is
pseudo welding
external audio radio silent
OK
check the phone reception
circuit
replace the FM antenna
check if the FM antenna is
damaged
repair the mainboard by referring to the
mainboard repair instructions

X249 L2 Service Manual
3.12 No Signal
YES
YES
NO
NO
YES
NO
NO
YES
NO
fix the antenna to the location
replace the mainboard
check the connection of
phone antenna
no signal
OK
check if the phone is in airplane
mode abnormality
adjust it to general mode
check the circuit of radio
frequency is OK
repair the mainboard by referring to
the mainboard repair instructions

X249 L2 Service Manual
3.13 Fail to Recognize T Card
YES
YES
YES
NO
YES
NO
YES
NO
YES
adjust its location
replace the mainboard
check if T card is installed
correctlly
fail to recognize T card
OK
check if T card is
damaged
replace the T card
check the circuit of T card
connector
replace the T card
connector
check if T card connector
is damaged
repair the mainboard by referring to
the mainboard repair instructions

X249 L2 Service Manual
3.14 Earphone Fault
YES YES
NO
YES
NO
NO
YES
NO
YES
repair or replace the earphone
replace the mainboard
check the USB interface of
earphone is soldering or broken
OK
check if the pin of mainboard USB
interface is soldering or out of shape
weld or replace the USB interface
check the related circuit of
USB outlet end
clean the matter
check if there is some
matter in the earphone
repair the mainboard by referring to
the mainboard repair instructions
earphone fault

X249 L2 Service Manual
3.15 Camera Shooting Abnormalities
YES
YES
NO
YES
NO YES
NO
NO
Thanks
For any Query or suggestion, Please write to [e-mail]
reinstall
check if the camera is
damaged
replace the camera
check the welding of
camera is good
camera shooting abnormalities
OK
check the circuit of
camera is normal
repair the mainboard by referring to
the mainboard repair instructions
replace the mainboard