LG -TM250 Service Manual
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LG -TM250 Service Manual

LG -TM250 Service Manual

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See also: User Manual , Quick Reference Manual
Features of LG-TM250
1. Wave Type
• CELLULAR : G7W
• PCS : G7W
2. Frequency Scope
Transmit Frequency (MHz)
PCS
CELLULAR
824.82 ~ 848.19
1850~1910
3. Rated Output Power : CELLULAR = 0.20W
4. Output Conversion Method : This is possible by correcting the key board channel.
5. Voltage and Current Value of Termination Part Amplifier (Catalogue included)
MODE
CELLULAR
PCS
6. Functions of Major Semi-Conductors
Classification
MSM6050-FBGA
MCP (TH50VPF5585ADSB)
RFR6000
RFT6100
7. Frequency Stability
• CELLULAR : ±0.5PPM
• PCS : ±0.1PPM
LG Electronics Inc.
Receive Frequency (MHz)
CELLULAR
PCS
869.82~893.19
1930~1990
PCS = 0.20W
Part Name
Voltage
CX77105
CX77107
Terminal operation control and digital signal processing
Flash Memory (32Mbit) + SRAM (32Mbit)
Storing of terminal operation program
Converts Rx RF signal to baseband signal
Converts baseband signal to Tx RF signal
GPS
1575.42
Current
4.0V
600mA
4.0V
700mA
Function
Power
0.20W
0.20W

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Summary of Contents for LG LG-TM250

  • Page 1 Features of LG-TM250 1. Wave Type • CELLULAR : G7W • PCS : G7W 2. Frequency Scope Transmit Frequency (MHz) Receive Frequency (MHz) CELLULAR CELLULAR 824.82 ~ 848.19 1850~1910 869.82~893.19 1930~1990 1575.42 3. Rated Output Power : CELLULAR = 0.20W PCS = 0.20W...
  • Page 2 LG-TM250 CDMA Mobile Subscriber Unit LG-TM250 SERVICE MANUAL Tri-Band, Tri-Mode [PCS/GPS/Cellular] CDMA Mobile Phone - 2 - LG Electronics Inc.

  • Page 3: Table Of Contents

    1. NAM Program Method and Telephone Number Inputting Method ......... 20 CHAPTER 3. Circuit Description 1. RF Transmit/Receive Part......................24 2. Digital/Voice Processing Part.....................29 CHAPTER 4. Trouble Shooting…………………………………………………………………….38 CHAPTER 5. Safety……………………………………………………………………………..…..44 CHAPTER 6. Glossary…………………………………………………………………………..…..47 CHAPTER 7. How to Download………………………………………………………………..…..?? APPENDIX……………………………………………………………………………………….…..60 - 3 - LG Electronics Inc.

  • Page 4: General Introduction

    LG-TM250 General Introduction The LG-TM250 phone has been designed to operate on the latest digital mobile communication technology, Code Division Multiple Access (CDMA). This CDMA digital technology has greatly enhanced voice clarity and can provide a variety of advanced features. Currently, CDMA mobile communication technology has been commercially used in Cellular and Personal Communication Service (PCS).

  • Page 5: System Introduction

    At this time, the spectrums of other signals that have different codes are not recovered into its original state, and appears as the self-interference of the system. - 5 - LG Electronics Inc.

  • Page 6: Features And Advantages Of Cdma Mobile Phone

    1.25msec (800 times per second). By doing so, the gain tolerance and the different radio propagation loss on the forward/backward link are complemented. - 6 - LG Electronics Inc.
  • Page 7 Unlike the existing analog cellular system, the CDMA system can reuse the same frequency at the adjacent cell. there is no need to prepare a separate frequency plan. Total interference generated on mobile station signals - 7 - LG Electronics Inc.
  • Page 8 In addition, in the CDMA system, services and service charges are classified further into different classes so that more transmit power can be allocated to high class service users for easier call set-up; they can also be given higher priority of using hand-off function than the general users. - 8 - LG Electronics Inc.

  • Page 9: Structure And Functions Of Tri-Band Cdma Mobile Phone

    (AGC Amp). Then, they are converted into RF band by the frequency synthesizer synchronizing these signals to proper output frequencies. Transmit signals obtained pass through the duplexer filter and then, are sent out to the cell site via the antenna. - 9 - LG Electronics Inc.

  • Page 10: Specification

    4.1.7 Antenna : Stubby Type (Helical&Meander), 50 Ω 4.1.8 Size and Weight 1) Size : 80 * 44 * 22.8 mm 2) Weight : 88 g (Approximately with standard battery) 4.1.9 Channel Spacing 1) CELLULAR : 1.25MHz 2) PCS: 1.25 MHz - 10 - LG Electronics Inc.
  • Page 11 4.2.6 Spurious Wave Suppression : Maximum of -80dB 4.2.7 CDMA Input Signal Range Dynamic area of more than -104~ -25 dB: 79dB at the 1.23MHz band. Transmit Band : below –60dBm Receive Band : below –80dBm - 11 - LG Electronics Inc.
  • Page 12 4.4.1 CELLULAR mode Ch # Center Freq. (MHz) Ch # Center Freq. (MHz) 1011 824.640 837.120 825.870 838.350 827.100 839.580 828.330 840.810 829.560 842.040 830.790 843.270 832.020 844.500 833.250 845.910 834.480 847.140 835.890 848.370 - 12 - LG Electronics Inc.
  • Page 13 4.5.1 CELLULAR mode Ch. # Center Freq. (MHz) Ch. # Center Freq. (MHz) 1011 869.640 882.120 870.870 883.350 872.100 884.580 873.330 885.810 874.560 887.040 875.790 888.270 877.020 889.500 878.250 890.910 879.480 892.140 880.890 893.370 - 13 - LG Electronics Inc.
  • Page 14 1948.75 1968.75 1175 1988.75 4.5.3 GPS mode : 1575.42MHz 4.6 Desktop Charger : See Appendix 4.7 Travel Charger : See Appendix 4.8 Cigar Lighter Charger : See Appendix 4.9 Hands-Free Kit : See Appendix - 14 - LG Electronics Inc.

  • Page 15: Installation

    1) The Battery pack is keyed so it can only fit one way. Align the groove in the battery pack with the rail on the back of the phone until the battery pack rests flush with the back of the phone. 2) Slide the battery pack forward until you hear a “click”, which locks the battery in place. - 15 - LG Electronics Inc.
  • Page 16 Press ‘Soft Key 2’ to edit A-key. 2-1-1) A-Key You can edit the A-Key. Press ‘Soft Key 1’ to save and go next NAM 1 items. Press ‘Soft Key 2’ to go previous NAM 1 items. - 16 - LG Electronics Inc.
  • Page 17 Press ‘Soft Key 2’ to go previous NAM 1 items. 2-5) NAM 1 Name You can edit NAM 1 Name. Press ‘Soft Key 1’ to save and go next more NAM 1 items. Press ‘Soft Key 2’ to go previous NAM 1 items. - 17 - LG Electronics Inc.
  • Page 18 2-9) NAM 1 True IMSI MCC You can edit NAM 1 True IMSI MCC. Press ‘Soft Key 1’ to save and go next NAM 1 items. Press ‘Soft Key 2’ to go previous NAM 1 items. - 18 - LG Electronics Inc.
  • Page 19 2-13) NAM 1 CDMA Home SID/NID You can edit NAM 1 Home SID/NID Pairs. Press ‘Soft Key 1’ to save and go next NAM 1 items. Press ‘Soft Key 2’ to edit NAM 1CDMA Home SID and NID. - 19 - LG Electronics Inc.
  • Page 20 2-17) NAM 1 CDMA Sec. CH B You can edit NAM 1 CDMA Secondary Channel B. Press ‘Soft Key 1’ to save and go next NAM 1 items. Press ‘Soft Key 2’ to go previous NAM 1 items. - 20 - LG Electronics Inc.
  • Page 21 You can edit NAM 1 Foreign SID Registration. Press ‘Soft Key 1’ to save and go next NAM 1 items. Press ‘Soft Key 2’ to go previous NAM 1 items. Press Up, Down key to choose YES/NO. - 21 - LG Electronics Inc.
  • Page 22 Press ‘Soft Key 2’ to edit NAM 2 related items. 2-24) Phone Model You can only see the Phone Model number. Press ‘Soft Key 1’ to go next items. Press ‘Soft Key 2’ to go previous items. - 22 - LG Electronics Inc.
  • Page 23 LG-TM250 2-25) Slot Cycle Index You can edit Slot Cycle Index Press ‘Soft Key 1’ to save Slot Cycle Index and exit Service Programming. Press ‘Soft Key 2’ to go previous items. - 23 - LG Electronics Inc.

  • Page 24: Chapter 3. Circuit Description

    After that, the 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. [Figure 1-1] Block Diagram of LG-TM250 - 24 -...
  • Page 25 It’s main function is to limit the bandwidth of spectrum reaching the LNA and mixer, attenuate receiver spurious response and suppress local oscillator energy. As a result frequency sensitivity and selectivity of mobile phone increase. The specification of LG-TM250 duplexer described below ;...
  • Page 26 The RFL6000(U110) is the integrated cellular and PCS LNA chipset. The characteristics of Low Noise Amplifier (LNA) are low noise figure, high gain, high intercept point and high reverse isolation. The frequency selectivity characteristic of mobile phone is mostly determined by LNA. The specification of LG-TM250 LNAs are described below: Parameter Low gain...
  • Page 27 The power amplifier that can be used in the PCS and CDMA mode has linear amplification capability and high efficiency. For higher efficiency, it is made up of one MMIC (Monolithic Microwave Integrated Circuit) for - 27 - LG Electronics Inc.
  • Page 28 RF frequency, an important consideration for Zero-IF processing. The VCO frequency used are 1715.56~1768.89 MHz for PCS and 1738.08~1787.94 MHz for cellular and they are produced in single voltage controlled oscillator of U140. - 28 - LG Electronics Inc.

  • Page 29: Digital/Voice Processing Part

    The memory part is made up of a flash memory, pseudo-SRAM for storing data. 2.2.5 Power Supply Part The power supply part is made up of circuits for generating various types of power, used for the digital/voice processing part. - 29 - LG Electronics Inc.

  • Page 30: Circuit Description

    When received, 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. - 30 - LG Electronics Inc.
  • Page 31 The logic part consists of internal CPU of MSM and MCP. The MSM6050 receives TCXO (=19.2MHz) from U141 and controls the phone in both CDMA and FM modes. The major components are as follows: CPU : ARM7TDMI microprocessor core - 31 - LG Electronics Inc.
  • Page 32 LCD module contains a controller which will display the information onto the LCD by 8-bit data from the MSM6050. It is also supplied stable 2.8V_MSMP by regulator(U403) for fine view angle and LCD reflects to improve the display efficiency. 4 LEDs are used to display LCD backlight. - 32 - LG Electronics Inc.

  • Page 33: Chapter 4. Trouble Shooting

    Voltage at 2,3,4 pin of U404 Less than 1.8V Change the U407 Voltage at 2,3,4 pin of U407 Less than 2.5V Change the U403 Voltage at 6 pin of U403 Less than 2.7V Change the main board - 33 - LG Electronics Inc.
  • Page 34 LG-TM250 2. When LCD isn't displayed. START Check pins of CON404 Operating voltage is not supplied in LCD module? Reconnect CON404 Change LCD LCD display ? Change LCD-FPCB LCD Display ? GOOD - 34 - LG Electronics Inc.
  • Page 35 Contact MIC contacting MIC is out Change MIC of order? Check Mic Bias Check U201 & U407 Volt of R206 & 4 pin of U407 is filter Check, Resoldering Network filter Network Change Main B’d - 35 - LG Electronics Inc.
  • Page 36 CON404 & check volt # 4 pin at pin 23,24 Of CON404 Earpiece soldering Soldering Earpiece between 2 earpiece Change Earpiece terminal 32Ω? EJACK_SENSE/ signal at #4 Check CON300(Earjack) pin of CON300 is High? Change Main B’d - 36 - LG Electronics Inc.
  • Page 37 23,24pin at hand set? of CON404 Good Soldering Earpiece soldering Earpiece Between Change Earpiece Earpiece EJACK_SENSE/ signal at #4 Check CON300 pin of CON300 is High? (Earjack) Change Main B’d - 37 - LG Electronics Inc.
  • Page 38 Paging to Handset with Sinewave appear at pin#31 of U17 Rectangular wave appear Soldering Buzzer collector Buzzer soldering OK? f Q405? Check CON404 , FPCB Rectangular Check Q405, wave appear at , Q406 base of Q406 Check - 38 - LG Electronics Inc.
  • Page 39 Change the Tx LDO (U401). Tx RF signal appears at Change the RF SAW C175? Filter (F150). Change the RFT6100 (U155). Change the Tx LDO (U401). Change the PLL LDO (U402). Change the main board. - 39 - LG Electronics Inc.
  • Page 40 Tx RF freq. appears at Change the SPDTswitch C571? (U521). Change the RF SAW Filter (F152). Change the RFT6100 (U155). Change the Tx LDO (U401). Change the PLL LDO (U402). Change the Main Board. - 40 - LG Electronics Inc.
  • Page 41 Filter (F112). Change the VCO (U140). Rx LO signal appears at Change the PLL LDO C455? (U402). Change the RFR6000 (U155). Change the Rx LDO (U405). Change the PLL LDO (U402). Change the Main Board. - 41 - LG Electronics Inc.
  • Page 42 Filter (F111). Change the VCO (U140). Rx LO signal appears at Change the PLL LDO C455? (U402). Change the RFR6000 (U155). Change the Rx LDO (U405). Change the PLL LDO (U402). Change the Main Board. - 42 - LG Electronics Inc.

  • Page 43: Chapter 5. Safety

    Do not hold the antenna when the phone is “IN USE”. Holding the antenna affects call quality and may cause the phone to operated at a higher power level than needed. - 43 - LG Electronics Inc.

  • Page 44: Electronic Devices

    Do not allow children to play with your phone. It is not a toy. Children could hurt themselves or others (by poking themselves or others in the eye with the antenna, for example). Children also could damage the phone, or make calls that increase your telephone bills. - 44 - LG Electronics Inc.

  • Page 45: Blasting Areas

    One Battery march Park, Quincy, MA 02269, Attn: Publication Sales Division. Rule of Thumb: Using common sense at all times when handling, installing or using the phone. Any questions should be directed to you nearest Service Center or authorized service technician or electrician. - 45 - LG Electronics Inc.

  • Page 46: Chapter 6. Glossary

    A-key. A secret, 64-bit pattern stored in the mobile station. It is used to generate update the mobile station’s Shared Secret Data. The A-key is used in the mobile station authentication process. - 46 - LG Electronics Inc.
  • Page 47 Candidate Set. The set of pilots that have been received with sufficient strength by the mobile station to be successfully demodulated, but have not been placed in the Active Set by the base station. See also Active Set. Neighbor Set, and Remaining Set. - 47 - LG Electronics Inc.
  • Page 48 Dedicated Control Channel. An analog conrtol channel used for the transmisson of digital control information from either a base station or a mobile station. Deinterleaving. The process of unpermuting the symbols that were permuted by the interleaver.. - 48 - LG Electronics Inc.
  • Page 49 Foreign SID Roamer. A mobile station operating in a system (SID) other than the one from which service was subscribed. See also Foreign NID Roamer and Roamer. Forward Analog Control Channel (FOCC). An analog voice channel used from a base station to a mobile - 49 - LG Electronics Inc.
  • Page 50 HLR. See Home Location Register. Home Location Register (HLR). The location register to which a MIN is assigned for record purposes such as subscriber information. Home System. The cellular system in which the mobile station subscribes for service. - 50 - LG Electronics Inc.
  • Page 51 Mean Input Power. The total received calorimetric power measured in a specified bandwidth at the antenna connector, including all internal and external signal and noise sources. Mean Output Power. The total transmitted calorimetric power measured in a specified bandwidth at the - 51 - LG Electronics Inc.
  • Page 52 Multiplex Sublayer. One of the conceptual layers of the system that multiplexes and demultiplexes primary traffic, secondary traffic, and signaling traffic. NAM. See Number Assignment Module. Narrow Analog. A type of voice channel that uses 10kHz channel spacing and subaudible signaling. - 52 - LG Electronics Inc.
  • Page 53 Packet. The unit of information exchanged between the service option applications of the base station and the mobile station. Padding. A sequence of bits used to fill from the end of a message to the end of a message capsule, typically to - 53 - LG Electronics Inc.
  • Page 54 Primary CDMA Channel. A CDMA Channel at a pre-assigned frequency assignment used by the mobile station for initial acquisition. See also Secondary CDMA Channel. Primary Paging Channel (CDMA). The default code channel (code channel 1) assigned for paging on a - 54 - LG Electronics Inc.
  • Page 55 Roamer. A mobile station operating in a cellular system (or network) other than the one from which service was subscribed. See also Foreign NID Roamer and Foreign SID Roamer. ROLR. See Receive Objective Loudness Rating. SAT. See Supervisory Audio Tone. - 55 - LG Electronics Inc.
  • Page 56 Status Information. The following status information is used to describe mobile station operation when using the analog system. Serving-System Status. Indicates whether a mobile station is turned to channels associated with System A or System B. - 56 - LG Electronics Inc.
  • Page 57 Traffic Channel Preamble. A sequence of all-zero frames that is sent at the 9600 bps rate by the mobile station on the Reverse Traffic Channel. The Traffic Channel preamble is sent during initialization of the Traffic - 57 - LG Electronics Inc.
  • Page 58 ‘0’ to 1 and ‘1’ to –1). Zone-Based Registration. An autonomous registration method in which the mobile station registers whenever it enters a zone that is not in the mobile station’s zone list. ㎲. Microsecond - 58 - LG Electronics Inc.

  • Page 59: Appendix

    5. Accessories - Desktop Charger - AC Adapter - Battery - Travel Charger - Hands-Free Car Kit (Portable) - Cigarrette Lighter Charger - Data Cable Kit - Headset - USB Cable Kit - Holster - 59 - LG Electronics Inc.

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