LG TCH-M550 User manual

SERVICEMANUALMODEL:TCH-M550
DETACHABLE FRONT
PANEL CAR CD RECEIVER
SERVICE MANUAL
MODEL : TCH-M550
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.

- 1-1 -
❍SECTION 1. SUMMARY
• SERVICING PRECAUTIONS .......................................................................................................... 1-2
• ESD PRECAUTIONS....................................................................................................................... 1-3
• SPECIFICATIONS........................................................................................................................... 1-4
❍SECTION 2. ELECTRICAL
• ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................. 2-1
• CD PART TROUBLESHOOTING GUIDE......................................................................................... 2-3
• WAVEFORMS OF MAJOR CHECK POINT .................................................................................. 2-11
• INTERNAL BLOCK DIAGRAM of ICs............................................................................................ 2-13
• BLOCK DIAGRAM......................................................................................................................... 2-25
• MAIN SCHEMATIC DIAGRAM....................................................................................................... 2-27
• FRONT SCHEMATIC DIAGRAM................................................................................................... 2-29
• CDP SCHEMATIC DIAGRAM ....................................................................................................... 2-31
• PRINTED CIRCUIT DIAGRAM...................................................................................................... 2-33
❍SECTION 3. CABINET MAIN CHASSIS & MECHANISM
• EXPLODED VIEW ........................................................................................................................... 3-1
❍SECTION 4. REPLACEMENT PARTS LIST.................................................................... 4-1
[CONTENTS]

- 1-2 -
❏SERVICING PRECAUTIONS
➊Always 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.
➋Do not defeat any plug/socket B+ voltage interlocks with which instruments covered by this service
manual might be equipped.
❸Do not apply power to this instrument and or any of its electrical assemblies unless all solid-state
device heat sinks are correctly installed.
❹Always connect a test instrument’s ground lead to the instrument chassis ground before
connecting the test instrument positive lead. Always remove the test instrument ground lead last.
1) The service precautions are indicated or printed on the cabinet, chassis or components. When servicing,
follow the printed or indicated service precautions and service materials.
2) The Components used in the unit have a specified conflammability and dielectric strength. When
replacing any components, use components which have the same ratings. Components marked in
the circuit diagram are important for safety or for the characteristics of the unit. Always replace with the
exact components.
3) An insulation tube or tape is sometimes used and some components are raised above the printed writing
board for safety. The internal wiring is sometimes clamped to prevent contact with heating components.
Install them as they were.
4) After servicing always check that the removed screws, components and wiring have been installed
correctly and that the portion around the service part has not been damaged. Further check the insulation
between the blades of attachment plug and accessible conductive parts.
SECTION 1. SUMMARY

- 1-3 -
❏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.
1) Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain
off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and
wear a commercially available discharging wrist strap device, which should be removed for potential
shock reasons prior to applying power to the unit under test.
2) After removing an electrical assembly equipped with ESD devices, place the assembly on a conductive
surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.
3) Use only a grounded-tip soldering iron to solder or unsolder ESD devices.
4) Use only an anti-static solder removal device. Some solder removal devices not classified as “anti-static”
can generate electrical charges sufficient to damage ESD devices.
5) Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESD
devices.
6) Do not remove a replacement ESD device from its protective package until immediately before you are
ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together
by conductive foam, aluminum foil or comparable conductive material).
7) Immediately before removing the protective material from the leads of a replacement ESD device, touch
the protective material to the chassis or circuit assembly into which the device will be installed.
CAUTION: Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
8) Minimize bodily motions when handling unpackaged replacement ESD devices. (Otherwise harmless
motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor
can generate static electricity sufficient to damage an ESD device).
[CAUTION. GRAPHIC SYMBOLS]
THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL
TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE
OF UNINSULATED “DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT
MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.
THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO
ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY
INFORMATION IN SERVICE LITERATURE.

- 1-4 -
1. GENERAL
Power requirements ..................................................................................................................... DC12V~15V
Ground system ................................................................................................................................... Negative
Dimensions(W x H x D) ...................................................................................................... 188 x 58 x 166mm
Weight .............................................................................................................................................. Net: 1.3kg
2. RADIO SECTION
FM AM(MW)
Frequency range 65.0~74.0MHz(Optional), 522~1,620kHz
87.5~108MHz (Optional:530~1,710kHz/ 520~1,620kHz)
Intermediate frequency 10.8MHz 450kHz
Usable sensitivity 12dBµV 32dBµV
Signal to noise ratio 55dB 45dB
3. COMPACT DISC SECTION
Frequency response..................................................................................................................... 40Hz~20kHz
Channel separation ...................................................................................................................... 50dB(1kHz)
Signal to noise ratio .................................................................................................................................. 60dB
4. AUDIO SECTION
Maximum output power ....................................................................................................................... 50W x 4
Speaker impedance ............................................................................................................... 4Ωx 4 or 8Ωx 4
NOTE: The design and specifications are subject to change without notice in the sourse of product
improvement.
❏SPECIFICATIONS

- 2-1 -
SECTION 2. ELECTRICAL
❏ELECTRICAL TROUBLESHOOTING GUIDE
Any Key power on.
Is power turnd on?
DISC loading?
Does initial reading occur?
Can disc be played?
Is audio output supplied?
Check power supply circuitry.
Q260, Q380, Q381, IC401 Pin3
IC201 Pin2
Check loading supply circuitry.
Q350,Q351,PN505, IC401 Pin1
Check laser circuitry.
Q501, IC502
Check focusing circuitry.
Q501,IC502
Check DISC.
Check tracking servo circuitry.
Q501,IC502
Check audio circuitry.
IC502,IC601,IC801
OK
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
(1) No Power.

- 2-2 -
YES
YES
YES
YES
YES
YES
(2) LCD light abnornal.
Any Key power on.
(without DISC)
Do display LCD then light? Check voltage in the power
supply circuitry.
Power supply circuitry
defective.
Q380,Q381,IC403
Reset circuit defective.
IC201 Surrounding circuit
defective.
X401, C413,C414 defective.
Q260, PN401 front PCB
pattern defective.
IC401, Pin 66,67,88,89 front
PCB pattern defective.
IC901, Surrounding circuit
PCB pattern defective.
Is u-com IC401 reset circuit
normal? Pin10
Is u-com IC401 keyin Pin9, 37
5volt input?
Is u-com IC401 Pin 66,67,88,89
output waveform normal?
Is IC901 Com1, Com2, Com3
output waveform normal?
Display LCD connector defective.
Is u-com IC401X1, X2 terminal
Pin38, 39 input?
OSC : 9.8304MHz
NO NO
NO
NO
NO
NO
NO

- 2-3 -

- 2-4 -

- 2-5 -

- 2-6 -

- 2-7 -

- 2-8 -

- 2-9 -

- 2-10 -

- 2-11 -
❏WAVEFORMS OF MAJOR CHECK POINT
#1. MICOM INTERFACE WAVEFORM
(CN503 1 9,2 1 ,1 8,20) during normal play
#2. SLED DRIVE AND MOTOR WAVEFORM
(IC504 pin5, 1 4) when focus search
#3. FOCUS DRIVE AND MOTOR WAVEFORM
(R5 1 3, IC504 pin 1 5)
•When focus search failed or there is no disc on the
tray
•There is disc on tray and focus search success

- 2-12 -
#4. SPINDLE DRIVE AND MOTOR WAVEFORM
(IC504 pin6, 1 2) when TOC reading
#5. TRACK DRIVE AND MOTOR WAVEFORM
(R508, IC504 pin23) during normal play
#6. RF, TRACKING AND FOCUS ERROR WAVEFORM
(IC502 pin8, 2 1 , 23) during normal play

- 2-13 -
■IC401 uPD784214A
1) PORT ASSIGNMENT
❏INTERNAL BLOCK DIAGRAM of ICs
TCH-M1000R/M550R
I/O is set by a standpoint of Micom
uPD784214A
PCD_PWR (O)
PTUN_PWR (O)
PPWR (O)
PTEL_MUTE (I)
PREMOTE (O)
PLIGHT (O)
N.C.
PSTANDBY (O)
V
DD
PEV_CLK (O)
PEV_DO (O)
N.C.
PCDC_PWR (O)
PCD_REV (O)
PLMT_ISW (I)
PCD_SW1 (I)
PCD_SW2 (I)
PCD_SW4 (I)
PCD_FWD (O)
N.C.
N.C.
TEST
N.C.
PPWR_MUTE (O)
N.C.
PAF_MUTE (O)
PCDC_DO (O)
N.C.
PDRV_OPS (O)
PDRV_MUTE (O)
PRDS_DI (I)
PST (I)
N.C.
N.C.
N.C.
PDSP_OCLK (O)
PDSP_ODA (O)
PDSP_IDA (O)
PBEEP (O)
PPLL_CE (O)
PPLL_CLK (O)
PPLL_DO (O)
PPLL_DI (I)
PFRT_CLK (O)
PFRT_DO (O)
N.C.
AV
REF1
N.C.
N.C.
AV
SS
N.C.
PVOLB (I)
PVOLA (I)
PKEY2 (I)
PKEY1 (I)
PLVL_MTR (I)
PS_MTR (I)
N.C.
AV
REF0
AV
DD
N.C.
PDSP_IDRF (I)
PDSP_ORST (O)
PDSP_OCEN (O)
N.C. N.C.
V
DD
9.8304 MHz 9.8304 MHz
V
SS
32.768 KHz 32.768 KHz
/RESET
PRDS_CLK (I)
PCD_IWRQ (I)
PCDC_DI (I)
PRMC (I)
N.C. N.C. N.C.
V
SS
N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. PACC (I) PANT (O) PFRT_DET (I) PFRT_RES (O) PFRT_CE (O) PCD_EJT (I)* POPT_OUT1 (O) POPT_OUT0 (O) POPT_IN2 (I) POPT_IN1 (I) POPT_IN0 (I)
*: TCH-M1000R only
Download Pin:
CLK : 38 pin (X1)
V
PP
: 22pin (TEST/VPP)
V
DD
: 9 pin (VDD), 37 pin (VDD), 51 pin (AVDD)
RESET : 43 pin (/RESET)
SCK : 67 pin (/SCK2)
SO : 66 pin (SI2)
SI : 65 pin (SOS2)
GND : 40 pin (VSS), 100 pin (VSS), 61 pin (AVSS)

- 2-14 -
2) PORT DESCRIPTION
Pin Name in Micom Name in Model Enable I/O I/O setted Output Format Descripation
1 P60/A16 PCD_PWR I/O O CMOS DSP power suppler ON output
2 P61/A17 PTUN_PWR I/O O CMOS Tuner power supplier ON output
3 P62/A18 PPWR I/O O CMOS System power supplier ON output
4 P63/A19 PTEL_MUTE I/O I - Telephone mute input
5 P64/RD PREMOTE I/O O CMOS External power amplifier enable output
6 P65/WR PLIGHT I/O O CMOS LCD backlight ON output
7 P66/WAIT N.C. I/O O CMOS Not to be used (Open)
8 P67/ASTB PSTANDBY I/O O CMOS To power amp, "STADN-BY" command output
9 VDD VDD - - - Positive power supply
10 P100/T15TO5 PEV_CLK I/O O CMOS Clock for interface with volume controller
11 P101/T16/TO6 PEV_DO I/O O CMOS To volume controller, data output
12 P102/T17/TO7 N.C. I/O O CMOS Not to be used (Open)
13 P103/T18/TO8 PCDC_PWER I/O O CMOS CD changer power supplier ON output
14 P30/TO0 PCD_REV I/O O CMOS In MD, load motor "reverse" command output
15 P31/TO1 PLMT_ISW I/O I - In MD, limit switch state input
16 P32/TO2 PCD_SW1 I/O I - In MD, SW1 state input
17 P33/TI1 PCD_SW2 I/O I - In MD, SW2 state input
18 P34/TI2 PCD_SW4 I/O I - In MD, SW4 state input
19 P35/TI100 PCD_FWD I/O O CMOS In MD, load motor "forward" command output
20 P36/T101 N.C I/O O CMOS Not to be used (Open)
21 P37/EXA N.C I/O O CMOS Not to be used (Open)
22 TEST/VPP TEST - - - pull down (470Ω~10kΩ)
23 P90 N.C I/O O N-ch Not to be used (Open)
24 P91 PPWR_MUTE I/O O N-ch To power amp, "Mute" command output
25 P92 N.C I/O O N-ch Not to be used (Open)
26 P93 PAF_MUTE I/O O N-ch To tuner pack, AF mute output
27 P94 PCD_IDO I/O O N-ch To CD changer, data output
28 P95 N.C I/O O N-ch Not to be used (Open)
29 P120/RTP0 PDRV_OPS I/O O CMOS In MD, motor driver's power save command output
30 P121/RTP1 PDRV_OMUTE I/O O CMOS In MD, all motor's output "cut off" command output
31 P122/RTP2 N.C I/O O CMOS Not to be used (Open)
32 P123/RTP3 PDSP_IDRF I/O I - Focusing OK signal input
33 P124/RTP4 PDSP_ORST I/O O CMOS DSP reser output
34 P125/RTP5 PCD_OCEN I/O O CMOS DSP chip enable output
35 P126/RTP6 N.C I/O O CMOS Not to be used (Open)
36 P127/RTP7 N.C I/O O CMOS Not to be used (Open)
37 VDD VDD - - - Positive power supply (+5V)
38 X2 X2 - - - X'tal 9.8304MHz
39 X1 X1 I - - X'tal 9.8304MHz
40 VSS GND - - - Ground
41 XT2 XT2 - - - Sub clock 32.768kHz
42 XT1 XT1 I - - Sub clock 32.768kHz
43 /RESET RESET I - - System reser input
44 P00/INTP0 PRDS_CLK I/O I - From tuner pack, RDS clock input
45 P01/INTP1 PCD_IWRQ I/O I - Sub-Q read standard level signal input
46 P02/INTP2/NMI PCDCDI I/O I - From CD changer, data input
47 P03/INTP3 PRMC I/O I - Remote controller's signal input (interrupt3)
48 P04/INTP4 N.C I/O O CMOS Not to be used (Open)
49 P05/INTP5 N.C I/O O CMOS Not to be used (Open)
50 P06/INTP36 N.C I/O O CMOS Not to be used (Open)
51 AVDD AVDD - - - Positive power supply to A/D converter
52 AVREF0 AVREF0 - - - Reference voltage applied to A/D converter
53 P10/ANI0 N.C I I - Not to be used (Open)
54 P11/ANI1 PS_MTR I I - Radio station's strength signl input
55 P12/ANI2 PLVL_MTR I I - Sound level's signal input
56 P13/ANI3 PKEY1 I I - Key # 1 line input
57 P14/ANI4 PKEY2 I I - Key # 2 line input
58 P15/ANI5 PVOLA I I - Encoder volume terminal #A input
59 P16/ANI6 PVOLB I I - Encoder volume terminal #B input
60 P17/ANI7 N.C - - - Not to be used (Open)

- 2-15 -
61 AVSS AVSS I/O I - Ground for A/D converter and D/A converter
62 P130/ANO0 N.C. I/O I CMOS Not to be used (Open)
63 P131/ANO1 N.C. I/O I CMOS Not to be used (Open)
64 AVREF1 AVREF1 I/O I - Reference voltage applied to A/D converter
65 P70/RxD2/SI2 N.C. I/O I CMOS Not to be used (Open)
66 P71/RxD2/SO2 PFRT_DO I/O I CMOS To LCD driver, data output
67 P72/ASCK2/SCK2 PFRT_CLK I/O I CMOS Clock output for interface with LCD driver
68 P20/RxD1/SI1 PPLL_DI I/O I - From PLL IC, data input
69 P21/TxD1/SO1 PPLL_DO I/O I CMOS To PLL IC, data output
70 P22/ASCK1/SCK1 PPLL_CLK I/O I CMOS Clock output for interface with PLL IC
71 P23/PCL PPLL_CE I/O I CMOS PLL IC enable output
72 P24/BUZ PBEEP - - CMOS Beep sound output (2.4kHz)
73 P25/SIO/SDA0 PDSP_IDA I/O O - From DSP, data input
74 P26/SO0 PDSP_ODA I/O O CMOS To DSP, data output
75 P27/SCK0/SCL0 PDSP_OCLK I/O O CMOS Clock output for interface with DSP
76 P80/A0 N.C. I/O O CMOS Not to be used (Open)
77 P81/A1 N.C. I/O O CMOS Not to be used (Open)
78 P82/A2 N.C. I/O I - Not to be used (Open)
79 P83/A3 PST I/O I - Sterep indigater's signal or SD signal input
80 P84/A4 PRDS_DI I/O I - From tuner pack, RDS data input
81 P85/A5 PORT_IN0 I/O I - For diode option check, signal 1 or 2 input 0
82 P86/A6 PORT_IN1 I/O I - For diode option check, signal 1 or 2 input 1
83 P87/A7 PORT_IN2 I/O I - For diode option check, signal 1 or 2 input 2
84 P40/AD0 PORT_OUT0 I/O O CMOS For diode option check, signal 1 output
85 P41/AD1 PORT_OUT1 I/O O CMOS For diode option check, signal 2 output
86 P42/AD2 PCD_EJT I/O I - Eject key input
87 P43/AD3 PFRT-CE I/O O CMOS LCD driver enable output
88 P44/AD4 PFRT-RES I/O O CMOS LCD driver reset output
89 P45/AD5 PFRT_DET I/O I - Front pannel existence signal input
90 P46/AD6 PANT I/O O CMOS Antenna control output
91 P47/AD7 PZCC I/O I - From ISO jack, ACC signal input
92 P50/A8 N.C. I/O O CMOS Not to be used (Open)
93 P51/A9 N.C. I/O O CMOS Not to be used (Open)
94 P52/A10 N.C. I/O O CMOS Not to be used (Open)
95 P53/A11 N.C. I/O O CMOS Not to be used (Open)
96 P54/A12 N.C. I/O O CMOS Not to be used (Open)
97 P55/A13 N.C. I/O O CMOS Not to be used (Open)
98 P56/A14 N.C. I/O O CMOS Not to be used (Open)
99 P57/A15 N.C. I/O O CMOS Not to be used (Open)
100 Vss VSS - - - Ground
inputportsetted 26
output port setted 31
Used I/O port 57
Interrupt 4
A/D Converter 4