cromax X458 User manual

X458 L2 Service Manual
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X458 L2 Service Manual
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CAUTIONS
Please read this service manual carefully and make sure all elements of anti-static are in
place before the repair work is carried out.
Servicing and alignment MUST be undertaken by qualified personnel only.
Please use specified tools and equipments for servicing, in which the parameters need to
be calibrated with specified criteria.
Chapter 1 Specification
Content
1. Brief Introduction
2. Exploded View
3. Tools
4. Disssembly
5. Picture of main board
A&B side of PCBA
A&B of PCBA Layout
6. Trouble Shooting Guide
7. CIT testing

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Specification :
Network: 850/900/1800/1900MHz
Display: 3.5“ HVGA 320*480
Camera: VGA(1.3M by Software)
BT:3.0
Memory: 64M+128M
Lithium Battery: Standard (1050mAh)
USB Data cable: USB 1.1
Features & Functions
Dual SIM Dual Standby Single working
Full touch
FM BT
WIFI
Multi-Media application
0.3MP with sw upgarde to 1.3MP
T-Flash（Support 8G T Card）
3.5“ HVGA 320*480
MP3、MP4、AVI 、3GP
USB1.1，Mini USB

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Chapter 2 Exploded View

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Chapter 3 Tools
Power Supply
Multimeter
Solder iron
Hot Air Gun
Solder wire, Flux
PC, Download cable
Others
Pick
Screw
Driver
Tweezer
Wrist
grounding
strap
Antistatic
gloves
Cable

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Chapter 4 Disassembly
1. Disassembly Process
1. Remove the battery cover
2. Unfasten the 4 screws by screw driver
4. Unfasten the 2 screws by screw driver.
5. Remove the TP connector.
3. Prize up the back cover
6. Stick protection film for front cover.
.

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Finished.
7. Remove the TP
8. Remove the LCD by electric soldering iron

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Chapter 4 Picture of PCBA
5.1 Side A
PCBA (Side A) Location of components
5.2 Side B
PCBA (Side B) Location of Components
(J201)battery
conector
I/O connector
U101
CPU
U800 wifi
chip
Mic
Camera
connector
U301
26MHZ
LCD
Connector
(U302)
RF PA
(U401)
FLASH
(J401)
Audio jack

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5.3 PCBA Layout side A
5.4 PCB Layout Side B

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CHAPTER 5 TROUBLESHOOTING
CANNOT POWER ON-CURRENT SWING INSTABILITY
Upgrade the
software is normal?
Cannot power on
Replace the
structural member.
Check the battery is
normal?
Check the battery
connector in normal?
Replace the PCBA is
normal?.
Replace the battery.
NO
NO
yes
NO
Replace the battery
connector.
yes
yes
Replace the PCBA.
NO

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REPAIR FLOW FOR PHONE DEAD
Phone dead
Upgrade the software can
settle the defect issue?
Clean and reinstall
the keypad or replace
the touch panel.
Check battery connector
and battery touch point if
is dropped or dirty?
Check the keypad if stuck
or touch panel do not work
to make the phone “dead”?
Replace the PCBA
Clean or replace
the battery or
battery connector.
YES
YES
No
No
No

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NO DISPLAY OR DISPLAY ABNORMALITY
No display or display
abnormality after power on
Check LCD connector
is OK or not
Resolder the LCD
connector can settle
the defect issue?
Replace the PCBA.
Check LCD if damage or
liquid flow out
Change LCD
Yes
Clean or reweld
the LCD connector
Yes
Change the LCD can
settle the defect issue?
No
Upgrade software
No

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INSERT SIM REPAIR PROCESS
NO
Replace SIM card
Replace the
PCBA.
Insert SIM
Clean or replace
SIM connector.
Clean or reweld the
SIM connector
Check SIM connector
is OK or not
OK
Check if all the SIM
pins are clean
NO
NO
Upgrade software can
settle the defect issue?
NO

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N0/WEAK SIGNAL TROUBLE SHOOING
No or weak
signal
Inspect the antenna and
antenna connector to see
if there’s any distortion
Replace the
defective
components.
Check and replace RF
connector to see if there’s
any signal
Replace the PCBA.
YES
YES
Replace RF
connector
NO

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NO/LOW SOUND FROM SPEAKER
Set the phone as
normal mode
Replace the PCBA
No sound or noise
Remove the speaker and
measure with multimeter
to see if there’s any
sound.
Replace speaker.
The phone is in
Silent mode.
Check and replace
FPC is ok or not.
.
Replace FPC.
Yes
NO
yes

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RECEIVER LOW VOICE OR NO VOICE
Measure the signal
with oscillograph
under calling mode
Receiver is low.
Check if receiver
connector is damaged.
Resolder or clean the
receiver connector.
Check if the receiver is
broken or damaged
Yes
NO
NO
Replace the
receiver .
Replace the PCBA.

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NO/LOW SOUND FROM MIC
No/Low sound from
MIC
NO
Yes
Check if there’s
MIC cover
Install the MIC
cover.
Press power on and side
button to test mode and
activate echo loop,
Replace the MIC
Replace the PCBA
YES

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Check charger and cable without
problem, or change good one
Upgrade the
software is normal?
No charge
DOES NOT CHARGE –NO CHARGE IN
YES
NO
NO
NO
NO
Change battery
Check if I/O connector
works normal
Replace the PCBA.
Replace the charger
or cable without
Re-solder or replace
the I/O connector

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CAN’T READ T-FLASH CARD
Can’t read
T-Flash card
NO
NO
Check if T-Flash slot
appearance was ok?
Replaced the
T-Flash slot
Check if T-Flash
FPC is normal?
Re-solder or
replace
FPC.
NO
Check if the T-Flash
connector is normal?
Re-solder or replace
the T-Flash connector.
Replace the
PCBA.
NO

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WIFI DEFECT REPAIR FLOW CHART
YES
NO
WIFI can’t open，
Can’t work normal
Software update and check
the function is OK or not
Upgrade Software
Check the WIFI antenna is
normal?
Check WIFI connector is
normal?
Replace the RF
connector
Replace the PCBA.
NO
Replace the
antenna.