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Table of Contents
Related Manuals for Micromax A27
Summary of Contents for Micromax A27
- Page 1 A27 Service Manual...
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Page 2: Table Of Contents
Table of Contents 1. Circuit diagram instruction ..................3 1.1 Main board explored view ................3 1.2 Detailed Description of Circuit Chart ............4 1.3 RF circuit ......................4 1.4 Base band circuit ..................... 5 1.5 Function circuit ....................5 2．Fault maintenance .................... -
Page 3: Circuit Diagram Instruction
1. Circuit diagram instruction .1 Main board explored view T-card connector direction sensor RF amplifier receiving filter FLASH SC6820 Battery connector 四方向传感器 射频放大器 接收滤波器 RF transceiver 26M crystal connector Earphone connector SIM connector TP connector WIFI/BT IC 32.768 Crystal IC LCD PAD... -
Page 4: Detailed Description Of Circuit Chart
1.2 Detailed Description of Circuit Chart RF PA transceiver (U112) U114 transceiver U103 SIM card 1 Key pad SIM card 2 Camera BT/WIFI T-card 1.3 RF circuit This phone is designed on SC6820 platform. RF main chip integration SR1019, PA use RDA6163A, TCXO uses 26MHz crystal oscillator. (1) Receiving circuit The GSM or DCS signal received from a base station via antenna is inputted from the pin 27 of U101, send U104/U105 to pin A20/B20/A19/B19. -
Page 5: Base Band Circuit
power amplifier and duplex switch. The I/Q signal is inputted to be performed signal modulation as the modulation signal. The modulated TXIF signals restrain its third harmonic by harmonic suppression filter. The follow-up TXIF signal will be sent to a discriminator on the offset frequency phase lock loop (OPLL). -
Page 6: Fault Maintenance
Camera 2．Fault maintenance Note: The PCBA repairing is a very important work during the final production of cellular phones. The speed and quality of repairing decides the yield and production efficiency. The repair idea is very important for a good repairing technician. Make sure not to heat a board right away once a phone reaches at hand. -
Page 8: Trouble Shooting And Flow Chart
3 Trouble shooting and flow chart 3.1 Unable to power on the handset Failure to power on Re-mount battery or Check battery mounted correctly & battery voltage >3.4V? replace battery Check if Keyboard backlight can be lighted Check if LCD is Pay attention to Download software! Ok? connected correctly... -
Page 9: No Ring Tone
3.2 No ring tone No ringtone Check soldering of Solder speaker.OK? speaker Replace speaker and OK! Mark the test failed speaker Mark the Check the speaker circuit mainboard with no short ciruit or open analysis result circuit Replace new mainboard... -
Page 10: Lcd Display Fault
3.3 LCD display fault Abnormal LCD Display Check If the lcd is damaged Replace new LCD Check if the lcd connector is Solder the lcd connector soldered well Check If the LCD is mounted Re-mount the lcd inverse Replace the new mainboard... -
Page 11: Charging Fault
3.4 Charging fault Failure to Charge Check charger or Replace new Replace new Charger charger Check battery is good or not Replace new battery Check charger connector for Solder charger connector soldering defect Check charging circuit of Mark the mainboard mainboard for fault with analysis result Replace new mainboard... -
Page 12: Camera Fault
3.5 Camera fault Failure to use camera Check camera for damage Replace new camera Check if camera is soldered or Solder camera connector assembled well or Re-assemble camera Mark the mainboard Check camera circuit for fault with analysis result Replace new mainboard... -
Page 13: Fail To Identify Sim Card
3.6 Fail to identify SIM card Failure to identify SIM card Check if SIM card is inserted correctly Reinsert or change new According to insertion direction SIM card Check Solder or replace SIM SIM connector for soldering connector defect Mark the mainboard Check SIM circuit for fault with analysis result Replace new mainboard... -
Page 14: Mic Fault
3.7 MIC fault Unable to record No sound in microphone Solder or replace new Check mic for soldering defect micphone Check if mic sound hole is Clean mic sound hole and jammed re-assemble mic Mark the mainboard with Check mic circuit for fault analysis result Replace new mainboard... -
Page 15: Keypad Fault
3.8 Keypad fault Keypad doesn’t work correctly Check : DOME is pasted and Paste the DOME or keymat is assembled correctly assemble keymat again Is there any dirty on keypad Clean keypad surface and surface? test Is sidekey soldered well? Solder or replace sidekey No short circuit Replace new mainboard... -
Page 16: Receiver Fault
3.9 Receiver fault No voice in receiver Is receiver ok ? Replace new receiver No broken wire Check receiver connector for Solder receiver connector soldering defect Check receiver circuit for any Mark the mainboard with fault analysis result Replace new mainboard... -
Page 17: Vibrate Fault
3.10 Vibrate fault Vibrator fault or No vibration Is vibrator soldered well ? Solder vibrator or replace vibrator Check : Wire of vibrator Replace vibrator isn’t broken Check vibrator circuit Mark the mainboard with No short circuit or open circuit analysis result Replace new mainboard... -
Page 18: Fm Fault
3.11 FM fault Failure to open FM or FM can’t scan any station Software version is correct Re-download software Earphone can be detected and Replace earphone audio output is ok Check FM circuit Mark the mainboard with No short circuit or open circuit analysis result Replace new mainboard... -
Page 19: Bluetooth Fault
3.12 Bluetooth fault Bluetooth can’t work Software version is correct Re-download software Is BT antenna assembled Re-assemble BT antenna correctly? Check BT circuit Mark the mainboard with No short circuit or open circuit analysis result Replace new mainboard... -
Page 20: No Signal
3.14 No signal No RF signal Is RF antenna assembled correctly? Re-assemble BT anntena Is the phone set into Flying Return to Normal mode mode? Mark the mainboard with Check RF circuit for any fault analysis result Replace new mainboard... -
Page 21: Failure To Identify T-Flash Card
3.15 Failure to identify T-flash card Failure to read T-flash card Is T-flash card inserted correctly? Re-insert T-flash card Check: the T-flash card is ok? Replace new card Clean socket or replace Check card socket is clean and socket no physical fault Mark the mainboard with Check card circuit for any fault analysis result... -
Page 22: Earphone Fault
3.16 Earphone fault Failure to use earphone Check: earphone is ok? Replace new earphone No damage Check earphone connector for Solder earphone connector soldering defect Is there any foreign matter in Clean or replace connector earphone connector? Check earphone circuit for any Mark the mainboard with fault analysis result... -
Page 23: Unable To Use Usb
3.17 Unable to use USB Uable to use USB Check : USB cable is ok, no pin of Replace new USB cable connector is broken Check if USB connector is Solder or replace USB solder ok, no short circuit connector Replace new mainboard...