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LG TCH-800 Service Manual

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SECTION 1. SUMMARY
• SERVICING PRECAUTIONS .......................................................................................................... 1-2
• ESD PRECAUTIONS ....................................................................................................................... 1-3
• SPECIFICATIONS ........................................................................................................................... 1-4
SECTION 2. ELECTRICAL
• ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................. 2-1
• INTERNAL BLOCK DIAGRAM of ICs .............................................................................................. 2-7
• BLOCK DIAGRAM ......................................................................................................................... 2-23
• MAIN SCHEMATIC DIAGRAM ...................................................................................................... 2-25
• CDP SCHEMATIC DIAGRAM ....................................................................................................... 2-27
• PRINTED CIRCUIT DIAGRAM ...................................................................................................... 2-29
SECTION 3. CABINET MAIN CHASSIS & MECHANISM
• EXPLODED VIEW ........................................................................................................................... 3-1
SECTION 4. REPLACEMENT PARTS LIST
[CONTENTS]
................................................................... 4-1
- 1-1 -

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  Summary of Contents for LG TCH-800

  • Page 1 [CONTENTS] SECTION 1. SUMMARY ❍ • SERVICING PRECAUTIONS ......................1-2 • ESD PRECAUTIONS ........................1-3 • SPECIFICATIONS ........................... 1-4 SECTION 2. ELECTRICAL ❍ • ELECTRICAL TROUBLESHOOTING GUIDE ................. 2-1 • INTERNAL BLOCK DIAGRAM of ICs ....................2-7 • BLOCK DIAGRAM ......................... 2-23 •...
  • Page 2: Section 1. Summary

    SECTION 1. SUMMARY ❏ SERVICING PRECAUTIONS – Always disconnect the power source before: 1) Removing or reinstalling any component, circuit board, module or any other instrument assembly. 2) Disconnecting or reconnecting any instrument electrical plug or other electrical connection. 3) Connecting a test substitute in parallel with an electrolytic capacitor in the instrument. CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explosion hazard.
  • Page 3: Esd Precautions

    ❏ ESD PRECAUTIONS [Electrostatically Sensitive Devices (ESD)] Some semiconductor (solid state) devices can be damaged easily by static electricity. Such omponents commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated circuits and some field-effect transistors and semiconductor chip components. The following techniques should be used to help reduce the incidence of component damage caused by static electricity.
  • Page 4: Radio Section

    ❏ SPECIFICATIONS 1. GENERAL Power requirements ........................DC12V~15V Ground system ........................... Negative Dimensions(W x H x D) ....................178 x 50 x 152.5mm Weight .............................. Net: 1.4kg 2. RADIO SECTION AM(MW) LW(Optional) Frequency range ......... 65.0~74.0MHz(Optional), 522~1,620kHz 144~281kHz 87.5~108MHz (Optional:530~1,710kHz/ 520~1,620kHz) Intermediate frequency .......
  • Page 5: Section 2. Electrical

    SECTION 2. ELECTRICAL ❏ ELECTRICAL TROUBLESHOOTING GUIDE (1) No Power ANY KEY POWER ON Check power supply circuitry. Is power turned on? Q505, Q506, IC201 Pin 39, Pin 87. Check Loading supply circuitry. DISC loading? Q401~ Q404, CW001 pin25, IC201 pin44. Check laser circuitry.
  • Page 6 (2) LCD light abnormal ANY KEY POWER ON (without DISC) Check voltage in the power Power supply circuitry defective. Do display LCD then light? supply circuitry. Q501, Q502, Q506, IC201 Is u-com IC201 reset circuit normal? Pin86 Reset circuit defective. IC201, Q505, Q506.
  • Page 7 (3) Initial reading is not carried out (with disc) Check voltage in the power DISC loading? supply circuitry . Q505, R506, IC201 pin39, pin87 CDP PCB: IC301. Is IC201 pin21 input waveform Does disc motor rotate? normal? Leaf SW contact defective. Connector defective.
  • Page 8 (A) when laser does not light. Is below signal “L” at IC101 Pin 70 (CDP PCB)? Has Pick-up returned to the Are data transferred from IC201 defective. IC201 Pin 27, 28, 37? innermost position? Is below signal output at IC201 Pin 26,27(CDP PCB)? IC101,201(CDP PCB) defective.
  • Page 9 (B) when laser light. Is signal output at focus search Do lenses move up and down? terminal? IC101 Pin48 (CDP PCB) IC101(CDP PCB) defective. Is signal output at IC301 Pin1, 2 (CDP PCB)? IC301 defective. Insert disc and Actuator short. in the case of Connector short.
  • Page 10 IC101(CDP PCB) defective. Is FE1 signal output ? Pick-up defective. IC501 Pin59 Connector defective. Is FE1 signal output at IC101 (CDP PCB) Pin31(ISTAT) ? IC101(CDP PCB) defective. ISTAT Is SMON signal output by IC201 (CDP PCB) Pin73? Pattern defective between IC201 Is SMPO signal output by IC201 Pin 72, 73, 75, 76 (CDP PCB) (CDP PCB) Pin75?
  • Page 11: Internal Block Diagram Of Ics

    ❏ INTERNAL BLOCK DIAGRAM of ICs I IC201 LC723764 (Micro-processor IC) 1) PORT ASSIGNMENT - 2-7 -...
  • Page 12: Port Description

    2) PORT DESCRIPTION ASSIGN NAME DESCRIPTION 4.5 MHz CRYSTAL INPUT TEST2 MCU TEST Port.Must be connected to GND. VREG BYPASS-CONDENSER Connecting PORT. VSSCPU Voltage Supplied PORT.(4.5V ~ 5.5V) SI0/PG3 No connection SO0/PG2 No connection PDTHSW SCK0/PG1 Front Panel connecting Detection PORT. Connection:LOW,/ Disconnection:HIGH ©...
  • Page 13 ASSIGN NAME DESCRIPTION MOTOR ON TAPE MAIN MOTOR ON PORT TAPE ON TAPE ON PORT. SUB MOTOR CONTROL PORT SUB MOTOR CONTROL PORT STAND-BY STAND-BY MODE DETECTOR PORT MODE SW TAPE HEAD LOCATION CHECK PORT REEL OUT TAPE REEL CHECK PORT TAPE MUTE PORT AMS MUTE DETECTOR PORT BEEP...
  • Page 14: Port Assignment

    I IC301 LC75421M (Electronic Volume controller IC) PORT ASSIGNMENT - 2-10 -...
  • Page 15 I IC701 LD4104 (LCD Driver IC) Block Diagram Pin Diagram - 2-11 -...
  • Page 16 I KB9223 (IC101 on CDP PCB: SSP) 80-QFP-1420C OVERVIEW The KB9223 is a 1-chip BICMOS integrated circuit to perform the func- tion of RF AMP and Servo signal processor for compact disc player application. It consist of blocks for RF signal processing, focus, tracking, sled and spindle servo.
  • Page 17: Pin Description

    PIN DESCRIPTION PIN DESCRIPTION Pin No. Symbol Description Capacitor connection pin for mirror hold Capacitor connection pin for defect Bottom hold. FRSH Capacitor connection pin for time constant to generate focus search waveform DCC2 The input pin through capacitor of defect bottom hold output DCC1 The output pin of defect bottom hold The peak frequency setting pin for focus, tracking servo and cut off frequency CLV LPF...
  • Page 18 PIN DESCRIPTION Pin No. Symbol Description MDATA Micom data input pin Micom data latch input pin RESET Reset input pin MIRROR The mirror output for test The output pin of focus OK comparator SSTOP The pin for detection whether pick_up position is innermost or ton The noninverting input pin of sled servo amplifier The output pin of sled servo amplifier The inverting input pin of sled servo amplifier...
  • Page 19: Block Diagram

    PIN DESCRIPTION Pin No. Symbol Description The output pin of(AVEE+AVCC)/2 voltage VCC for RF part RF summing amplifier inverting input pin RF summing amplifier output pin The input pin for AGC The output pin for AGC The input pin for EFM comparison The capacitor connection pin for AGC Feedback input pin of E I/V amplifier EF Balance control GND for RF part...
  • Page 20 - 2-16 -...
  • Page 21 PIN DESCRIPTION Pin No. Symbol Description AVDD1 Analog VCC1 DPDO Charge pump output for Digital PLL DPFIN Filter input for Digital PLL DPFOUT Filter output for Digital PLL CNTUOL VCO control voltage for Digtial PLL AVSS1 Analog Ground1 DATX Digital Audio output data X’tal oscillator input XOUT X’tal oscillator output...
  • Page 22 PIN DESCRIPTION (continued) Pin No. Symbol Description Latch Signal input from Micom(Schmit Trigger) MDAT Serial data input from Micom(Schmit Trigger) Serial clock input from Micom(Schmit Trigger) SRAM data I/O port8(MSB) SRAM data I/O port7 SRAM data I/O port6 SRAM data I/O port5 SRAM data I/O port4...
  • Page 23 PIN DESCRIPTION Pin No. Symbol Description LOCK Output signal of LKFS condition sampled PBFR/16(if LKFS is “H”, LOCK is “H”, if LKFS is sampled “L” at least 8 times by PBFR/16, LOCK is “L”) PBFR Write frame clock(Lock:7.35KHz) SMEF LPF time constant control of the spindle servo error signal SMON ON/OFF control signal for spindle servo DVDD2...
  • Page 24 - 2-20 -...
  • Page 25 I IC302 TDA8571J V P1 V P2 V P3 V P4 MODE OUT1+ 30 K • OUT1- OUT2+ 30 K • OUT2- SGND V DIAG DIAGNOSTIC OUT3+ 30 K • OUT3- V ref OUT4+ 30 K • OUT4- PGND1 PGND2 PGND3 PGND4 MGG153...
  • Page 26 MEMO - 2-22 -...
  • Page 27 ❏ BLOCK DIAGRAM 2-23 2-24...
  • Page 28: Main Schematic Diagram

    ❏ MAIN SCHEMATIC DIAGRAM 2-25 2-26...
  • Page 29: Cdp Schematic Diagram

    ❏ CDP SCHEMATIC DIAGRAM 2-27 2-28...
  • Page 30: Printed Circuit Diagram

    PRINTED CIRCUIT DIAGRAM 1. FRONT PCB TOP 2. TRIM PCB BOTTOM 2. TRIM PCB TOP 1. FRONT PCB BOTTOM 2-29 2-30...
  • Page 31: Main Pcb Bottom

    3. MAIN PCB BOTTOM 2-31 3-32...
  • Page 32 3. MAIN PCB TOP 2-33 3-34...
  • Page 33 4. CDP BOTTOM 2-35 2-36...
  • Page 34 4. CDP TOP 2-37 2-38...
  • Page 35: Section 3. Cabinet Main Chassis & Mechanism

    SECTION 3. CABINET MAIN CHASSIS & MECHANISM I EXPLODED VIEW CAUTION NOTE) Refer to “SECTION 4 REPLACEMENT PARTS LIST” in order to look for the Exposed blade will cause part number of each part. severe injury...
  • Page 36 MEMO MEMO...