LG LG-YD636 Service Manual Download Page 14 | Manualshive

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3.1.3

Checking VCTCXO Circuit

Circuit Diagram

Test Point

Checking Flow

Check U101 Pin 3

◆

Refer to Graph

3

-1(a)

Check U101 Pin 4

◆ Refer to Graph

3

-1(b)

19.2MHz OK?

+2.85V OK?

No

Yes

VCTCXO Circuit is Ok
See next Page to check
Duplexer

Check U401

No

Yes

Changing U101

U101. 3

U101. 4

Waveform

Graph

3

-1(a)

Graph

3

-1(b)

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Summary of Contents for LG-YD636

Page 1: ...CDMA MOBILE SUBSCRIBER UNIT LG YD636 SINGLE BAND CDMA MOBILE PHONE SERVICE MANUAL ...

Page 2: ... Input Method Inputting of telephone numbers included 1 Telephone Number and NAM Programming Method CHAPTER 2 Circuit Description 1 RF Transmit Receive Part 2 Digital Voice Processing Part CHAPTER 3 Trouble Shooting CHAPTER 4 Safety ...

Page 3: ...ding process and then searching signal 2 NAM Input Method Inputting of telephone numbers included 1 Telephone Number and NAM Programming Method Press 159753 in idle state Then the following Menu is appeared 1 Service Menu 2 Test Screen 3 Test Call 4 Vocoder Set 5 Verify ADM 6 Error Screen 7 Del Error SlotCycle Idx Phone Model Press 1 to program the telephone number and NAM Phone model displayed th...

Page 4: ...Enabled NAM 1 CDMA Home System Reg NAM 1 CDMA Foreign SID Reg NAM 1 CDMA Foreign NID Reg NAM 1 CDMA Home SID NID NAM 1 Lock out SID NID NAM1 CDMA Primary CH A NAM1 CDMA Primary CH B NAM1 CDMA Secondary CH A NAM1 CDMA Secondary CH B Editing this items is not recommended 3 FCC TEST MENU 1 FCC TEST MENU Press 159753 in idle state Left Right Key in an effort to move to the DEBUG MENU2 Select CDMA FCC ...

Page 5: ... RF signal is amplified by the Power Amp in order to have enough power for radiation Finally the RF signal is sent out to the cell site via the antenna after going through the duplexer 1 2 Description of Receive Part Circuit 1 2 1 Duplexer EFSD836MD2S2 The duplexer consists of the Rx bandpass filter BPF and the Tx BPF which has the function of separating Tx and Rx signals in the full duplex system...

Page 6: ...ncludes the LNA quadrature downconversion and baseband functions Numerous secondary functions are integrated on chip the Rx LO generation and distribution circuits the UHF VCO circuits and various interface control and status circuits The Cellular CDMA receive signal is routed from the antenna to the RFR6122 IC via the duplexer The analog baseband outputs interface with one of MSM6025 devices that...

Page 7: ...ift King OQPSK I and Q are 90 deg out of phase and I and I are 180 deg The mixers in RFT6122 converts baseband signals into RF signals After passing through the upconverters RF signal is inputted into the Power AMP RFT6122 Cellular CDMA RF Specifications Parameter Condition Min Typ Max Units Rated Output Power Average CDMA Cellular 6 0 dBm Min Output Power Average CDMA Cellular 75 dBm Rx band nois...

Page 8: ...he digital voice processing part is made up of a keypad LCD receptacle part voice processing part mobile station modem part memory part and power supply part 2 2 Configuration 2 2 1 Keypad LCD and Receptacle Part This is used to transmit keypad signals to MSM6025 It is made up of a keypad backlight part that illuminates the keypad LCD part that displays the operation status onto the screen and a r...

Page 9: ...he keypad LCD lights up through the use of 16 LEDs The terminal status and operation are displayed on the screen for the user with the characters and icons on the LCD Moreover it exchanges audio signals and data with external sources through the receptacle and then receives power from the battery or external batteries 2 3 2 Audio Processing Part MIC signals are amplified through OP AMP inputted in...

Page 10: ...ived I and Q data are demodulated into symbols by the demodulator and then de interleaved in reverse to the case of transmission Then the errors of data received from viterbi decoder are detected and corrected They are voice decoded at the vocoder in order to output digital voice data 2 3 4 Memory Part Memory part consists of 64 Mbits Flash Memory and 32 Mbits Static RAM the Flash Memory part are ...

Page 11: ...all the circuitry Some of the features of the ARM microprocessor include a 3 stage pipelined RISC architecture both 32 bit ARM and 16bit THUMB instruction setsm a 32 bit address bus and a 32 bit internal data bus FLASH Memory Flash Memory is used to store the program of the mobile station Using the down loading program the program can be changed even after the mobile station is fully assembled SRA...

Page 12: ...ettiing Oscilloscope Setting 1 Check PMIC Circuit 2 Check VCTCXO Circuit 3 Check Control Signal 4 Check Duplexer Mobile SW 5 Check Rx I Q data Redownload SW CAL 3 1 1 When Tx power isn t enough Checking Flow Test Point 1 2 3 4 5 3 1 Rx Part Trouble CHAPTER34 Trouble Shooting CHAPTER 3 Trouble Shooting ...

Page 13: ...r Circuit Circuit Diagram Test Point Checking Flow Check Pin 29 of U401 Check Pin 7 of U401 2 6V_Rx OK No Pin 7 High No Changing Board PMIC Circuit is OK See next Page to check VCTCXO Replace U401 U401 29 2 6V_Rx U401 7 High ...

Page 14: ...oint Checking Flow Check U101 Pin 3 Refer to Graph 3 1 a Check U101 Pin 4 Refer to Graph 3 1 b 19 2MHz OK 2 85V OK No Yes VCTCXO Circuit is Ok See next Page to check Duplexer Check U401 No Yes Changing U101 U101 3 U101 4 Waveform Graph 3 1 a Graph 3 1 b ...

Page 15: ... 5 SBST Check Pin 3 4 5 Refer to Graph 3 2 a b Check SBDT SBCK SBST Check if there is Any Major Difference Refer to Graph 3 2 a b Level is High Similar Yes No Yes No Download the SW Download the SW Control Signal is Ok See next Page to Check Duplexer SBDT SBCK SBCK SBST Graph 3 2 a Graph 3 2 b ...

Page 16: ...3 1 5 Checking Duplexer Mobile SW Test Point Circuit Diagram U100 1 DP100 8 DP100 5 ...

Page 17: ...Graph 3 3 b Check DP100 Pin 5 Check if there is Any Major Difference Refer to Graph 3 3 c Detected Signal Yes No Changing U100 Duplexer is Ok See next Page to check Rx I Q data Signal Detected Signal Detected Signal Yes No No Check C101 Changing DP100 Yes Rx TEST SETUP HHP Test Channel 610 E5515C Setup CH 610 Sector Power 30 dBm Spectrum Analyzer Settiing Oscilloscope Setting U100 Pin 1 Graph 3 3 ...

Page 18: ...DP100 Pin 8 DP100 Pin 5 Graph 3 3 b Graph 3 3 c ...

Page 19: ...Rx_Q_N R136 Rx_I_N R135 Rx_I_P R135 Rx_I_P R138 Rx_Q_P R136 Rx_I_N R137 Rx_Q_N Checking Flow Check R138 R137 R136 R135 Check if there is Any Major Difference Refer to Graph 3 4 a b Similar Yes No Replace U107 Redownload the Software Calibrate Graph 3 4 a Graph 3 4 b ...

Page 20: ...ey insert FCC Mode Set CH400 AGC 400 Spectrum analyzer setting Oscilloscope setting 1 Check Regulator Circuit 2 Check VCTCXO Circuit 3 Check SBI Control Signal 4 Check RFT6122 Circuit 5 Check PAM Control Signal 6 Check Duplexer Mobile SW Redownload SW CAL RFT6122 PAM DUPLEXER VCTCXO Mobile SW ...

Page 21: ... POINT Circuit Diagram Checking Flow VREG_RFTX 2 6V OK TP214 TX ON High Replace U201 Replace U401 Regulator Circuit is OK See Next Page to Check VCTCXO Check Pin29 U401 U201 YES YES NO NO MSM6025 U401 Pin29 V_RFTX 2 6V U201 TP214 TX ON ...

Page 22: ...agram Waveform Checking Flow Pin 3 19 2MHz OK VCTCXO Circuit is OK See next page to check SBI control signal YES NO Pin4 2 85V OK Replace U101 NO Check U401 U101 YES U101 Pin3 VCTCXO OUT U101 Pin4 2 85V_TCXO U101 Pin3 VCTCXO_OUT U101 Pin4 2 85V_TCXO ...

Page 23: ...Signal Test Point Circuit Flow Level is appear YES NO Similar NO Control Signal is OK See next page to check RFT6122 Circuit Check TP202 YES Download the SW Download the SW Waveform U106 RFT6122 TP202 SBST SBDT SBCK SBCK SBST ...

Page 24: ...vel near 1V is Appear NO Control Signal is OK See next page to check PAM Circuit Check C174 C175 YES Check U201 Replace U106 Check U106 Pin12 NO Output signal 837MHz is Appear YES Check U106 Pin23 Replace U106 C174 C175 I Q DATA U106 Pin12 TX_CP U106 Pin23 CELL_OUT C174 C175 TX_I Q DATA U106 Pin23 CELL_OUT ...

Page 25: ...3 2 5 Check PAM Circuit Test Point Circuit Diagram U100 Pin4 Vreg 2 85V U104 Pin4 RF_IN U102 Pin3 Vout U104 Pin2 Vreg 2 85V U104 Pin9 10 11 Vcc2 U104 Pin12 RF_OUT U104 Pin5 Vcc1 ...

Page 26: ...ulpexer Mobile SW Check U104 Pin4 YES Check U104 Pin2 NO Level is 3 3V 4 2V OK YES Check U102 Pin3 Check F100 Check Q100 U401 NO Level is 3 3V 4 2V OK YES Check U104 Pin5 9 10 11 Check U102 Replace U104 NO Output Level is Appear YES Check U104 Pin12 Replace U104 Waveform U104 Pin4 RF_IN U104 Pin12 RF_OUT ...

Page 27: ...Mobile SW TEST POINT Circuit Flow Level is Appear YES NO Level is Appear NO Redownload SW and Recalibration Check DP100 Pin8 YES Replace DP100 Replace U100 Check U100 Pin2 Circuit Diagram DP100 Pin8 TX ANT U100 Pin2 ANT_OUT ...

Page 28: ... PM6610 FUNCTIONAL BLOCK DIAGRAM3 3 3 3 Logic Part Trouble ...

Page 29: ...3 3 1 Power On Trouble Circuit Diagram Test Point 2 85V_RUIM 1 9V_MSMC PM6610 POWER MANAGEMENT SECTION 2 85V_TCXO 2 6V_RX 2 6V_TX 2 6V_MSMA 2 85V_MSMP U401 PM6610 ...

Page 30: ...sewhere The Phone will power on Replace the main board Check the contact of power key or dome switch Push power on key and check the level change of U401 PWR_ON_SW Check the voltage of the following port at U401 2 6V_MSMA 2 85V_RUIM 1 9V_MSMC 2 85V_MSMP 2 85V_TCXO 2 6V_RX 2 6V_TX Logic level at PWR_ON_SW of U401 Low Does it work properly Does it work properly YES YES YES YES NO NO NO NO NO YES ...

Page 31: ...3 3 2 Charging Trouble Test Points Q401 R438 C410 R411 R415 CHARGER CIRCUIT PART Block Circuit Diagram R411 C410 R415 Q401 R438 OΩ PM6610 CHARGING CONTROL BLOCK PM6610 ...

Page 32: ...or TA is out of order Change the charging adaptor Re soldering Q401 R415 R438 R411 Q401 R415 R438 R411 well soldered Voltage across R415 is 100mV YES YES YES NO NO YES Replace R415 0 7V Voltage Q401 1 3V NO Replace R415 Is the battery charged NO The battery may have the problem Change the battery and try again Charging will operate properly YES ...

Page 33: ...3 3 3 Receiver Trouble Test Points RECEIVER CONNECTOR PART Circuit Diagram RECEIVER PART EAR10 EAR10 CON403 R300 R301 C370 Block Diagram RECEIVER CODEC BLOCK ...

Page 34: ...the soldering R300 R301 YES Replace the Main board MSM6025 is out of order Re soldering R300 R301 Check the contact state of Receiver connector Replace the Receiver The Receiver will work properly Waveform C370 EAR10 C370 EAR10 RMS 349 mV RMS 349 mV AC voltage of the signals AC VOLTAGE OF THE SIGNALS WAVEFORM ...

Page 35: ...face Trouble Test Points USB TRANCEIVER PART Block Diagram Connecting MSM6025 toFive WireInterface Transceiver X200 R201 USB RESONATOR C313 C312 R376 Q300 R311 C310 C309 C308 C307 L301 C311 R318 R320 C306 U301 DP1681 ...

Page 36: ...Circuit Diagram USB TRANSCEIVER USB RESONATOR ...

Page 37: ...Waveform USB Interface waveform D D ...

Page 38: ...L301 Replace U301 L301 Replace main board MSM6025 is out of order Logic level at USB_PWR_ON Low USB_SENSE Low Check the signal level at R318 Is it almost 3 3v YES YES NO NO Check the soldering R376 R318 R320 Re soldering R376 R318 R320 Replace U301 The USB interface will work properly X200 is working Oscillator frequency 48 MHz YES NO Check the soldering X200 R201 Re soldering X200 R201 Replace X2...

Page 39: ...3 3 5 Speaker Trouble Test points Circuit Diagram U402 C447 C425 R457 R455 R430 R426 CON300 SPK PHONE AUDIO AMP PART SPK CONNECTOR PART SPK PHONE AUDIO AMP ...

Page 40: ...Check the soldering C425 R430 Replace MSM Check the soldering of PIN 1 of U402 Check the Soldering of R426 Re soldering Pin5 Pin8 of U402 Replace MSM Check the signal level of PIN5 PIN8 of U402 Check the Soldering of R455 R457 CON300 Re soldering R426 Check the state Of contact of speaker Speaker will work properly Replace U402 Re soldering R455 R457 CON300 NO NO NO NO NO NO NO NO Yes Yes Yes Yes ...

Page 41: ...Test points Circuit Diagram R434 C456 C455 MIC FILTER PART MIC MIC BIAS PART MIC FILTER MIC 3 3 6 MIC Trouble ...

Page 42: ... R434 Replace MSM Check the signal level At each side of MIC Is It a few tens mVAS Replace the microphone Check the soldering of C455 C456 Re solder C455 C456 Check the soldering of MIC Filter Part Re solder MIC Filter part MIC will work properly Checking Flow Waveform Yes Yes Yes Yes No No No No No Yes ...

Page 43: ...3 3 7 Vibrator Troble Checking Flow Block Circuit Diagra PM6610 VIBRATION CONTROL BLOCK U401 R437 PM6610 PART MOTOR CONNECTOR PART MOTOR MOTER_EN CON402 ...

Page 44: ... at pin 10 Of U401 near OV Check the soldering Of pin10 at U401 Re solder pin10 of U401 Replace U401 Check the soldering of R437 Re solder R437 Check the state at Contact of Vibrator Re contact vibrator Replace Vibrator Vibrator will Work properly No No No No Yes Yes Yes Yes Yes ...

Page 45: ...3 3 8 Key Backlight LED Trouble Test Points Circuit Diagram LED409 LED407 LED403 LED405 LED406 LED408 LED400 LED401 LED402 LED404 KEYPAD INDICATOR LIGHT PART KEYPAD INDICATOR LIGHT ...

Page 46: ...T 3 6 4 2V Are all LEDs LED400 409 working Q400 Q402 is working BACKLIGHT WILL WORK PROPERLY Charge battery Check the soldering of each R or replace LEDs not working Check the condition of Q400 402 If problem Change Q400 402 No No No Yes Yes Yes ...

Page 47: ...ECTED Change the UIM Our Phone supports 3V UIM only Resolder or replace CON400 No No No Yes Yes Yes SETTING Insert UIM CON400 and power on Check MSM Good Change UIM card Does it work Properly Re download SW Work Replace Main board The UIM is malfunctioned Change the UIM Yes Yes No No Test Points Circuit Diagram CON400 UIM SOCKET PART PIN 1 No UIM SOCKET ...

Page 48: ...3 3 10 Earphone Trouble Test Points Circuit Diagram CON401 C460 Q401 U402 R450 Q408 C443 Q409 EAR MIC JACK RADIO PART PIN 3 PIN 4 EAR MIC JACK RADIO ...

Page 49: ...o mode Earphone detect problem Audio path problem Can you hear your voice from the earphone Change Earphone Set the audio part of the test equipment to continuous wave mode Earphone receiving Path problem Can you hear the sound from the earphone Earphone sending path problem 1 4 2 3 Yes No Yes No Earphone receiving path problem 2 Level of C460 is about 1 2V Check soldering of Pin3 of CON401 Change...

Page 50: ...e solder Q408 Replace Q408 4 No 5 Earphone sending path problem Earphone detect problem Earphone sending path problem 3 Level pin4 of CON401 is about 2 6V Level of C225 is About a few tens or hundreds VAC Re solder R207 R208 Re solder C225 Does it work well Re download software Does it work well 4 Change main board No No Yes Yes Yes Yes No No No No Yes Yes Yes ...

Page 51: ...uble LCD Control signals From MSM D 0 15 LCD_RESET1 A 1 LCD_CS LWR Check point The assembly status of the LCD Module The Soldering of connector CON301 L300 LCD CONNECTOR PART Test Points Circuit Diagram LCD CONNECTOR ...

Page 52: ...r 2 5V Check the Control signal D 0 15 LCD_RESET1 A 1 LCD_CS LWR LCD display will work properly Change the LCD Module No No No Yes Yes Yes Re soldering L300 Replace L300 Check CON301 soldering Re solder CON301 Check soldering L300 No Yes YES ...

Page 53: ...E and in 1992 the American National Standards Institute ANSI updates the 1982 ANSI Standard for safety levels with respect to human exposure to RF energy Over 120 scientists engineers and physicians from universities government health agencies and industry after reviewing the available boy of research developed this updated Standard In March 1993 the US Federal Communications Commission FCC propos...

Page 54: ...le driving please Give full attention to the driving Use hands free operation if available and pull off the road and park before making or answering a call if driving conditions require Electronic Devices Most modem electronic equipment is shielded from RF energy However RF energy from cellular telephones may affect inadequately shielded electronic equipment RF energy may effect improperly install...

Page 55: ...explosive atmosphere It is rare but your phone or accessories could generate sparks Sparks in such area could cause an explosion or fire resulting in bodily injury or even death Areas with a potentially explosive atmosphere are often but not always clearly marked They include fueling areas such as gas station below deck on boats fuel or chemical transfer or storage facilities areas where the air c...

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