Mobile phone Basic Troubleshooting
Mobile phone Basic Troubleshooting
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This type of problem are arise in mobile phone . how to solve this type of problem below details ..............
- No power on
- Battery voltage problem
- Network problem
- Display problem
- CTP problem
- Camera problem
- Receiver & Speaker & MIC no sound
- Vibrator problem
- Earphone problem
- WIFI/BT problem
- Light/Proximity sensor problem
No power on
No power on
Check point
Check point
- if fixed battery mobile phone no power on at first charging the device minimum 15/20 minutes
- Check the battery voltage with the digital multi meter (3.6-4.2V), you need to charge when voltage is too low.
- Check the USB port, make sure no man-made damage or intrusion corrosion.
- Check the battery connector, make sure no out of shape or damage or poor contact.
- Check power switch key FPC/button.
- Check the mainboard, make sure no intrusion corrosion.
- Update the software.
Check with DC power supply & See the current value
Check with DC power supply & See the current value
Phone’s current consumption and check point:
Phone’s current consumption and check point:
- If Current=0mA, check power path and power switch path.
- If 0mA<current<10mA, check main clock(26MHz Crystal).
- If 10mA<current<100mA, Update software and check CPU/Memory.
- If current>400mA, check whether leakage or short circuit.
- Check I/0 connector & ID pin must be clean
Battery voltage problem
Battery voltage problem
- Check the battery, make sure no man-made damage or bad battery(such as intrusion/corrosion/swell).
- Charge the battery.
- Test the voltage of VBUS on the USB connector, if the voltage is not 5.2V, maybe the charger or the USB connector problem, change and test it again.
- Test the voltage of VBUS test point on the mainboard, if the voltage is not 5.2V, maybe the main FPC or the mainboard problem, change and test it again.
- Test the voltage of VBAT test point on the mainboard, if the voltage is 0V or low, short VBAT and VBUS to activate the battery.
- If the problem still exists, please change the mainboard.
Network problem
Network problem
- Check the SIM card, if SIM can't been read, check the SIM card and the SIM slot.
- Check software, software version may result in bad signal.
- Check the antenna FPC, make sure no man-made damage
- Check the antenna spring and the RF socket, make sure they are OK.
- Check the coaxial cable, make sure it is good.
- Check the IMEI code, make sure it is right. *#06#
- Check the psnNumber,
- •If the phone is formatted, you need to write calibration parameters and WIFI/BT MAC address.
Display problem
Display problem
- Check the LCD, make sure no man-made damage or intrusion corrosion.
- Check software, make sure it is right, for some phone, different LCD version has different software, need to select right software.
- Check whether LCD is assembled well.
- Check the LCD FPC connector/connector on the mainboard, make sure it is in good condition.
- Cross-validate the mainboard, if it is mainboard problem, change the mainboard
CTP: capacitive touch panel
CTP: capacitive touch panel
- Check the CTP, make sure no man-made damage or intrusion corrosion.
- Check software, make sure it is right, for some phone, different CTP version has different software, need to select right software.
- Check whether CTP is assembled well.
- Check the CTP FPC connector/connector on the mainboard, make sure it is in good condition.
- Check the VGP1/SCL0/SDA0/RST/INT test point on the mainboard.
- Cross-validate the mainboard, if it is mainboard problem, change the mainboard.
Camera problem
Camera problem
- At First Update software
- Check camera soldering point /base.
- Always make factory setting after replace the camera.
- If the HS has two camera, first remove front camera and restore setting then check.
- If back camera is ok check front camera.
MIC & Receiver & Speaker no sound
MIC & Receiver & Speaker no sound
Following Problems will happen if the Mic is Faulty:
Following Problems will happen if the Mic is Faulty:
- No sound or Less Sound during phone call.
- The other Person cannot hear your Voice / Sound.
- Sound with interruption or Changed sound.
Check With multimeter
Check With multimeter
- Check MIC hole.
- Check Sub-PCBA, MIC & FPC.
- Check MIC terminal voltage (1.8 to 2.8 volt) .
- Check bias voltage.
- Check MIC related component have any missing.
- Check headphone connector / Headphone symbol
Following Problems will happen if the Receiver is Faulty:
Following Problems will happen if the Receiver is Faulty:
- No sound during phone call.
- Low sound during phone call.
- Sound with interruption.
- receiver noise
Check With multimeter
Check With multimeter
- Check Volume first.
- Make Restore settings.
- Check the (+) Positive and (-) Negative of the Speaker.
- Check Receiver (Receiver resistivity 32 ohm)
- Check bias voltage.
- Check Receiver related component have any missing.
- Check headphone connector / Headphone symbol.
- Dust clean (filter cloth ).
Following Problems will happen if the Speaker / Loudspeaker is Faulty:
Following Problems will happen if the Speaker / Loudspeaker is Faulty:
- Ringer / Loud Speaker not working
- Low sound from the Speaker
- Sound coming from Speaker but with interruption
- Sound not clear
- Cannot Play Music or No Sound from Video
- Phone Not Ringing during incoming call
- Phone Vibrates but won’t ring
Check With multimeter
Check With multimeter
- Check Volume first.
- Make Restore settings.
- Check the (+) Positive and (-) Negative of the Speaker .
- Check Speaker (Speaker resistivity 8 ohm)
- Check bias voltage.
- Check Ringer related component have any missing.
- Check headphone connector / Headphone symbol.
Vibrator problem
Vibrator problem
Following Problems will happen if the Vibrator is Faulty:
Following Problems will happen if the Vibrator is Faulty:
- Vibrator not working.
- Vibration with interruption.
- Vibration Hangs.
- Phone will ring but wont vibrate.
Check With multimeter
Check With multimeter
- Check Settings in Mobile Phone for Vibrator. Check if Vibrator is ON or OFF.
- Make Restore settings.
- Check the (+) Positive and (-) Negative of the Vibrator .
- Check Vibrator (Vibrator resistivity 8~16 ohm)
- If the problem is not solved then disassemble the mobile cell phone and clean tips and connector of Vibrator / Motor.
Earphone problem
Earphone problem
- MIC problem, check the earphone cable, then check the MIC pin of the earphone socket, make sure it is good and touch the earphone well.
- One side/both side of the earphone doesn't work, Check the earphone socket and check the small components of earphone circuit.
- Doesn't show earphone icon when the earphone is plugged in, Check the earphone socket and small component of earphone circuit.
WIFI/BT problem
WIFI/BT problem
- Check whether it is WIFI/BT setting problem or old software problem.
- Weak WIFI/BT signal, short transmission distance but can't turn WIFI/BT on, check the WIFI/BT antenna FPC and the antenna spring on mainboard, make sure they are good, no broken and damaged.
- Check the small components around the antenna spring on the mainboard, make sure they are OK.
Proximity sensor problem
Proximity sensor problem
- Check whether there are dust cover the light/proximity sensor area on the TP.
- Check whether photosensitive gum cover assemble well, no losing, no excursion, no extruding.
- Check the sensor on the mainboard and the small components around it.
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