LG -500 Series Repair Manual
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LG -500 Series Repair Manual

LG -500 Series Repair Manual

Gsm phone
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GSM Phone
REPAIR MANUAL
GSM Handsets 
Lab.
MODEL : LG­500 
Series

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Summary of Contents for LG LG-500 Series

  • Page 1 GSM Phone REPAIR MANUAL MODEL : LG­500  Series GSM Handsets  Lab.

  • Page 2: Table Of Contents

    Table of Contents 1. INTRODUCTION .………………………………… 5. ENGINEERING MODE ……………… 1.1 Purpose .…………………………………..…... 5.1 BB Test ……………………………… 1.2 Abbreviations ………………………………... 5.2 Trace Test ………………………… 5.3 S/W Version ………………………… 2. TEST SETUP ………………………………..…..5.4 SIM Lock …………………………… 2.1 Setup .…………………………………..…..5.5 Call Timer …………………………… 5.6 Fact.

  • Page 3: Introduction

    1. INTRODUCTION GSM Handsets  Lab. ...

  • Page 4: Purpose

    1. INTRODUCTION Purpose 1.1 Purpose This manual provides the information necessary to repair, description and download the features of the LG-500 series, specially this book has the chip aim of our repair men to improve their ability. • Applicability This trouble shooting is only applicable to professional engineer for repai ring mobile phone.

  • Page 5: Abbreviations

    1. INTRODUCTION Abbreviations 1.2 Abbreviations Baseband UART Universal Asynchronous Low Drop Output Receiver/Transmitter Light Emitting Diode Intermediate Frequency CC-CV Constant Current–Constant Liquid Crystal Display Voltage Printed Circuit Board Cigar Lighter Adapter PSTN Public Switched Telephone Digital to Analog Converter Network Digital Communication System Radio Frequency Digital Signal Processing...
  • Page 6 1. INTRODUCTION Attention ATTENTION Boards, which contain Electrostatic Sensitive Device (ESD), are indicated by the sign. Following information is ESD handling: • Service personnel should ground themselves by using a wrist strap when exchange system boards. • When repairs are made to a system board, they should spread the floor with anti-static mat which is also grounded.

  • Page 7: Test Setup

    2. TEST SETUP GSM Handsets  Lab. ...

  • Page 8: Setup

    (8960) GPIB OSCILLOSCOPE CABLE GPIB GPIB COM1 GPIB COMPUTER POWER RF IN/OUT SUPPLY MOBILE RF CABLE LG 500 RS-232 CABLE I/O Connector 500 I/O CON. CABLE PIF(LG-500 JIG) DIP S/W UART SPECTRUM ANALYZER PHONE POWER POWER CABLE HIGH FREQUENCY PROBE GSM Handsets ...

  • Page 9: Power Supply

    2. TEST SETUP How to setup A. Computer 1. Put GPIB card to the extended slot of personal computer. If you have a notebook PC, you need PCMCIA card for GPIB. 2. Connect the RS-232 cable between COM port of your PC and MON port or UART port of PIF.
  • Page 10 2. TEST SETUP How to setup D. PIF(JIG for LG 500) 1. Connect I/O connector cable for 500 to PIF phone port. 2. Connect the power cable ro PS port of PIF. 3. Connect the RS-232 cable ro PIF MON or UART.
  • Page 11 2. TEST SETUP How to setup D. PIF(JIG for LG 500) JTAG2 JTAG1 AUDIO Status PHONE UART Power UART Status DC IN + PS - GSM Handsets  Lab. ...

  • Page 12: Assembly Instruction

    3. ASSEMBLY INSTRUCTION GSM Handsets  Lab. ...
  • Page 13 3. ASSEMBLY INSTRUCTION GSM Handsets  Lab. ...

  • Page 14: Disassembly Of Upper Case

    3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3.1 Disassembly of Upper Case 1. Push the battery locker, and then remove the battery cover. 2. Pull the battery downward and lift it up. 3. Use your thumb to pull down the battery-locker hard. GSM Handsets  Lab. ...
  • Page 15 3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 4. Loosen the 4 screws as shown below. 5. While the Lower case is detached from the Upper case, twist the lower case to the right for disassembling a hook. Then twist it again to the left for disassembling the other hook.

  • Page 16: Disassembly Of Upper-Case Components

    3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3.2 Disassembly of Upper-Case Components 1. Release the screws and lift up the speaker holder to remove the speaker. 2. Use a '-' type driver carefully to lift up the Lower case of the vibrator spindle. Assembly : - Make sure the terminal of Speaker is being attached towards the Antenna.
  • Page 17 3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3. Use a small '-'type driver to insert into the direction and lift it up to remove the battery spring. 4. Also, for the SIM-card cover, use '-'type driver to remove it. 5. Release the Volume BTN by pushing it with opposite force onto each side. And for the Recording BTN, just push one its side to release it.

  • Page 18: Disassembly Of Lower Case

    3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3.3 Disassembly of Lower Case 1. Use a '-' type driver to release from the hooks on Lower case. Then, lift up the PCB for final disassembly. 2. Insert a small '-'type driver between the shield-can and cover, and lift up along the flat side of the lower case.
  • Page 19 3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3. Lift up the rubber part of multi-key, and then the Dial BTN will be disassembled from the Lower Case. 4. While holding the Lower case with your left hand, use your right hand to twist the flip-cover to the hinges.

  • Page 20: Disassembly Of Lower Case Components

    3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3.4 Disassembly of Lower-Case Components 1. Use a pin to lift up the microphone to the direction as shown below. 2. Use a pin to release the Receiver. GSM Handsets  Lab. ...
  • Page 21 3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3. Insert a '-'type driver between the hinge and the Lower case, and lift it up to remove the hinge. 4. See the cover from the A-direction as shown below, and assemble a pink hinge on its left and a green hinge on its right. GSM Handsets ...

  • Page 22: Disassembly Of Pcb

    3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 3.5 Disassembly of PCB 1. Lift up the side hooks as shown in fig.4-9. Then the main PCB and the LCD Module will be disassembled. Assembly: - Insert guide-hooks of LCD Module into guide-holes of Main PCB and push it in until it clicks.
  • Page 23 3. ASSEMBLY INSTRUCTION Disassembly/Reassembly 2. Use a '-'type driver to push away the antenna hook, and then disassemble the Antenna. Assembly : Push the Antenna into the hole until it clicks. GSM Handsets  Lab. ...

  • Page 24: Assembly

    3. ASSEMBLY INSTRUCTION Assembly 3.6 ASSEMBLY 1. Hang the Main PCB onto the hook on Lower case and push it down. 2. Connect the lead wire of Speaker and Vibrator to the Main PCB. Make sure that the poles are facing right directions. 3.

  • Page 25: Download

    4. DOWNLOAD GSM Handsets  Lab. ...

  • Page 26: Download Equipment

    4. DOWNLOAD Download Setup 4.1 Download Equipment 1. Data Kit 2. Desktop or Notebook PC 3. Download Monitor Program 4. LG-500 mobile phone To RS-232 Port Data Kit for LG 500 GSM Handsets  Lab. ...

  • Page 27: Data Kit Download Procedure

    In order to download software of LG-500, the following working environments should be prepared : LG-500 Data Link Kit, DK-10G that is connected to COM1 or COM2 serial port in the Desktop or Notebook PC. LG-500 Data Kit Download Monitor Program that is copied to Desktop PC or Notebook PC.

  • Page 28: Using Download Program

    4. DOWNLOAD Using Download Program 4.3 Using Download Program 1. Unzip LG-500 UART Download monitor program (monitor632.zip) in PC. 2. Execute monitor632.exe. And then select the "Target" Menu shown below. Then, choose "Connect" in the Target Menu. GSM Handsets  Lab. ...
  • Page 29 4. DOWNLOAD Using Download Program 3. A table will be displayed as shown below. Then press the arrow-button and choose a correct serial port. And press "OK" button. GSM Handsets  Lab. ...
  • Page 30 4. DOWNLOAD Using Download Program 4. As the following window shown in Fig A is displayed, connect LG-500 Phone to Data Link Kit, DK-10G and power on LG-500. If the connection is succeeded, the following screen will show the contents as shown Fig B.
  • Page 31 4. DOWNLOAD Using Download Program 5. Click on "Flash" on the top menu and select "Erase and Program Appli Only" item as shown in Fig 5. GSM Handsets  Lab. ...
  • Page 32 4. DOWNLOAD Using Download Program 6. Finally choose the target SW that you want to download. And then you can see the following window in Fig 6. GSM Handsets  Lab. ...
  • Page 33 4. DOWNLOAD Using Download Program 7. If the downloading procedure is succeeded, then the following window is shown. GSM Handsets  Lab. ...

  • Page 34: Engineering Mode

    5. ENGINEERING MODE This mode is used to certify that which part is needed to repair so simply. This part is consist of Baseband test, Trace test, SW version and so on. Enter : 2945# * A. About Engineering Mode Engineering mode is designed to allow a service man/engineer to view and test the basic functions provided by a handset.
  • Page 35 5. ENGINEERING MODE 5.1 Baseband Test [MENU 1] A. LED Test [1-2] This menu is to test the indicator LED on top left hand corner of a handset and backlight LED in the LCD module. • Auto Test [1-2-1] • Indicator On [1-2-2] : Green light turns on and menu is changed to “Indicator Off”.
  • Page 36 5. ENGINEERING MODE C. Keypad Test [1-4] D. Melody Test [1-5] • Auto Test [1-5-1] • Melody Pattern [1-5-2] • Melody Volume [1-5-3] E. Vibrator [1-6] F. Battery Test [1-7] G. Serial Port Test [1-8] H. Audio Gain Test [1-9] •...

  • Page 37: Trace Test

    5. ENGINEERING MODE 5.2 Trace Test [MENU 2] S/W Version [MENU 3] : This displays software version stored in the phone. 5.3 Eng Mode [MENU 4] 5.4 SIM Lock [MENU 5] 5.5 Call Timer [MENU 6] A. All Calls [6-1] : This displays total conversation time. User cannot reset this value. B.

  • Page 38: Trouble Shooting

    6. Trouble Shooting Power Supply 6.1 Power Supply Failure : Power-ON button is not working. Solution : - Check the voltage level of battery. - If voltage level < 3.32V, Charge the battery. - If voltage level > 3.32V, Go on to the next page. GSM Handsets ...
  • Page 39 6. Trouble Shooting Power Supply Failure : Power-ON button is not working. Solution : - Check the level of U605.8 (ONnOFF) - If voltage level is low(<2V), Power-On sequence is not executed properly.Try again. - If voltage level is high(>3V) ,check the LCD module and backlights.

  • Page 40: Voice

    6. Trouble Shooting Audio 6.2 Audio Failure : MIC is not working. Solution : - Connect the phone to the test network and make a R601 call. - Check the signal level at point R601(upper side) If voltage level << 2.5V, R602 Check the connectivity of R601, R602.
  • Page 41 6. Trouble Shooting Audio Failure : MIC is not working. Solution : - Check the signal level at the U601.5 and U602.5 U601 after putting audio signal in MIC. A few hundreds of mV levels have to be measured. U602 If not, replace U601 or U602.
  • Page 42 6. Trouble Shooting Audio Failure : MIC is not working. Solution : - Check the connectivity of MIC component. Replace the MIC. Try again. MIC Contact PAD GSM Handsets  Lab. ...

  • Page 43: Troubleshooting

    6. Trouble Shooting Voice Failure : Receiver is not working. Solution : - Connect the phone to the test network and make a call. - Check the signal level at the point U604.4 after putting audio signal in MIC. A few hundreds of mV U604 levels have to be measured.
  • Page 44 6. Trouble Shooting Voice Failure : Receiver is not working. Solution : - Check the connectivity of receiver component. Replace the receiver. Try again. Receiver Contact PAD Receiver GSM Handsets  Lab. ...
  • Page 45 6. Trouble Shooting Voice Failure : Melody is not heard. Solution : - Check the connectivity of speaker. Go on to the next page. GSM Handsets  Lab. ...
  • Page 46 6. Trouble Shooting Voice Failure : Melody is not heard. Solution : - Check the signal level at the point U605.5 (VCC). If voltage level << 3V, replace the LDO(U605). Go on to the next page. U605 GSM Handsets  Lab. ...
  • Page 47 6. Trouble Shooting Voice Failure : Melody is not heard. Solution : - Check the melody signal level at the point U603.12 or U603.11. A few hundreds of mV levels have to be measured. If not, replace Melody IC U603 12 11 (U603).

  • Page 48: Display

    6. Trouble Shooting Display 6.3 Display Failure : LCD display is not working. Solution : - Normal state contact of Disassemble LCD module LCD module with LCD Contact Pin connector on PCB. - Check “Is LCD connector well soldered onto PCB?” If not, re-soldering LCD connector.
  • Page 49 6. Trouble Shooting Display Failure : LCD display is not working. Solution : - Check “Are R719 & R720 well soldered onto PCB?” If not, re-soldering R719 R719 R720 and R720. Go on to the next page. GSM Handsets  Lab. ...
  • Page 50 6. Trouble Shooting Display Failure : LCD display is not working. Solution : - Check “Are R725~R729 R725 well soldered onto PCB?” If not, re-soldering R725~ R727 R729. R728 R729 - Replace the LCD module. R726 GSM Handsets  Lab. ...

  • Page 51: The Other Function

    6. Trouble Shooting The Other Function 6.4 The Other Function Failure : Vibrator is not working. Solution : - Check in the Engneering mode [2945#*16]. - Check whether J701 is well connected to the vibrator lines or not. Vibrator If not, resoldering… (J701) &...
  • Page 52 6. Trouble Shooting The Other Function Failure : Vibrator is not working. Solution : - Check the R732 voltage level. (high=approx. 3V) R732 If not, replace R732. - Check “Is the R731 well T702 mounted?” R731 If not, re-mount R709 - Check the T702 collector level.
  • Page 53 6. Trouble Shooting The Other Function Failure : Vibrator is not working. Solution : - Check the signal level at R730 the point R730, L701. (about 1V) If not, replace R703 L701 or L701 - Replace J701(Vibrator) GSM Handsets  Lab. ...
  • Page 54 6. Trouble Shooting The Other Function Failure : LED (Keypad Backight) is not emitted. Solution : - Check “Are R709 & R710 T701 well mounted?” If not, re-mount R709 and R710. R710 - Check the T701.4 voltage R709 level. (high=approx. 3V) If not, replace T701…...
  • Page 55 6. Trouble Shooting The Other Function Failure : LED (Keypad Backight) is not emitted. Solution : - Check LED pin 1 voltage D704 (= battery voltage) D703 D705 D701 If not, replace battery. - Replace D701~D708, one by one. D708 D706 D702 D707...
  • Page 56 6. Trouble Shooting The Other Function Failure : LED (LCD Backight) is not emitted. Solution : - Check “Are R723 & R724 well mounted?” If not, re-mount R723 and R724. R723 - Check the T704.6 voltage R724 level. (high=approx. 3V) T704 If not, replace T704…...
  • Page 57 6. Trouble Shooting The Other Function Failure : LED (LCD Backlight) is not emitted. Solution : - Check “Are R780~R783 well mounted?” R780 R783 If not, re-mount R780~R783. R781 D711 R782 - Replace D711~D714, one D713 by one. D712 D714 GSM Handsets ...
  • Page 58 6. Trouble Shooting The Other Function Failure : Charging is not working. Solution : - Check “Is the battery pack well connected to the phone?” If not, reassemble battery pack. - Check the battery voltage level. (3.2~4.2V) “YES” Check indicator LED. “NO”...
  • Page 59 6. Trouble Shooting The Other Function Failure : Charging is not working. Indicator Solution : Check indicator LED. Check indicator LED. - Check the indicator LED (state:ON) when charger is connected. If not, replace the battery. - Check whether Indicator LED has ON state within 3 minutes or not.
  • Page 60 6. Trouble Shooting The Other Function Failure : Charging is not working. Solution : Check TA, CLA, DTC Check TA, CLA, DTC - Check TA, CLA, DTC voltage (5.2V, 800mA) If not, replace TA, CLA and DTC. Go on to the next page. GSM Handsets ...
  • Page 61 6. Trouble Shooting The Other Function Failure : Charging is not working. Solution : - Check the T501 voltage level. (0.65~0.9V) If not, replace T501. T501 - Check the D501 voltage level. (<0.3V) If not, replace D501. Go on to the next page. D501 <...
  • Page 62 6. Trouble Shooting The Other Function Failure : Charging is not working. J502 Solution : (I/O Connector) - Check the R508 voltage level. (<0.12V) If not, replace R508. - Check “Are the J502, J503 J503 well connected to PCB?” If not, re-mount J502 R508 or J503.
  • Page 63 6. Trouble Shooting The Other Function Failure : Receiving Signal Failure. Solution : - “no RSSI or weak signal” Antenna spring Antenna pad Check contact between antenna spring and pad at PCB. : Stretching the spring to the direction of PCB pad. Go on to the next page.
  • Page 64 6. Trouble Shooting The Other Function Failure : Receiving Signal Failure. Solution : - Upgrade Software to the latest version & Test again… RF Calibration (If possible) LG 500 & Test again… PIF(LG-500 JIG) DIP S/W UART PHONE POWER GSM Handsets  Lab. ...

  • Page 65: Appendix A.1 Rf Components

    Appendix. RF Components A.1 RF Components BPF400 BPF401 N300 BPF400,403:DCS SAW filter BPF401,402:GSM SAW filter U400 BPF404:IF SAW filter SW300 SW300:Ant. Switch U400:VCTCXO  U401 U401:PLL BPF404 U402:TRF6053 (Main chip) U403:TXVCO  U402 U302 U301:Dual PAM IC300:APCIC U403 N300:Directional coupler BPF403 IC300 BPF402 GSM Handsets  Lab. ...

  • Page 66: Rx Test

    Appendix. Rx Test A.2 Rx Test Receiver RF Levels ­40dBm ­46dBm ­65dBm ­50dBm ­55dBm EGSM F i l t e r RXIN RXIP ­63dBm I R F 1225MHz RF F i l t e r RXQN RXQP 1560 .8MHz ­63dBm 564MHz /13 , Ou t p u t...
  • Page 67 Appendix. Rx Test Test Points of Rx Levels GSM Handsets  Lab. ...
  • Page 68 Appendix. Rx Test Test Points of Rx Levels U401 : PLL GSM Handsets  Lab. ...

  • Page 69: Tx Test

    Appendix. Tx Test A.3 Tx Test Transmitter RF Levels ­10dBm 29dBm Synthesizer (XRF2253) EGSM : 545MHz DCS : 543MHz VCTCXO ( VC-TCXO-208C ) /13 , OSCIN Ou t p u t D i v i d e r 13MHz I F /N RF2V8 VCO_TANK+ PA_ON...
  • Page 70 Appendix. Tx Test Test Points of Tx Levels U401 : PLL GSM Handsets  Lab. ...

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