LG TCH-M800 Service 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
• INTERNAL BLOCK DIAGRAM of ICs
..............................................................................................
2-7
• BlOCK DIAGRAM .......................................................................................................................... 2-32
• MAIN SCHEMATIC DIAGRAM
......................................................................................................
2-34
• CDP SCHEMATIC DIAGRAM
.......................................................................................................
2-36
• PRINTED CIRCUIT DIAGRAM
......................................................................................................
2-38
❍
SECTION 3. CABINET MAIN CHASSIS & MECHANISM
• EXPLODED VIEW
...........................................................................................................................
3-1
❍
SECTION 4. REPLACEMENT PARTS LIST
...................................................................
4-1
[CONTENTS]
- 1-2 -
❏ SERVICING PRECAUTIONS
➊ 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.
➋ Do not defeat any plug/socket B+ voltage interlocks with which instruments covered by this service
manual might be equipped.
❸ Do not apply power to this instrument and or any of its electrical assemblies unless all solid-state
device heat sinks are correctly installed.
❹ Always 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.
- 2-1 -
SECTION 2. ELECTRICAL
❏ ELECTRICAL TROUBLESHOOTING GUIDE
(1) No Power
ANY KEY POWER ON
YES
YES
YES
YES
YES
YES
NO
Check power supply circuitry.
Q505, Q506, IC201 Pin 39, Pin 87.
NO
Check Loading supply circuitry.
Q402, Q404, Q406, Q409.
CW001 pin17, pin 4 IC201 pin21.
NO
Check laser circuitry
.
CDP : Q30, IC30, IC31, IC34, IC35.
Check focusing circuitry
.
CDP PCB: IC30, IC34, IC35.
Check DISC.
NO
Check tracking servo circuitry.
CDP PCB : IC30, IC34, IC35.
NO
Check audio circuitry.
IC201, IC302 CDP PCB: IC30~IC34.
Is power turned on?
DISC loading?
Does initial reading occur?
Can disc be played?
Is audio output supplied?
OK
- 2-2 -
(2) LCD light abnormal
ANY KEY POWER ON
(without DISC)
YES
NO
Check voltage in the power
supply circuitry.
YES
Is u-com IC201 reset circuit
normal? Pin86
4.8V
0V
NO
Power supply circuitry defective.
Q501, Q502, Q506, IC201
NO
Reset circuit defective.
IC201, Q505, Q506.
YES
Is u-com IC201 Xin,Xout terminal
Pin 1,100 input?
OSC : 4.5MHz
NO
CT201, CC201, CC202 defective.
YES
Is u-com IC201 keyin Pin7 Pin45
0volt input?
NO
CN201,front PCB pattern
defective.
YES
Is u-com IC201 Pin46, 47, 48
output waveform normal?
5V
NO
IC201 pin46~48,front PCB
pattern defective.
Is IC701 com1, com2, com3
output waveform normal?
Display LCD connector defective.
5V
NO
IC701 Surrounding circuit PCB
pattern defective.
Do display LCD then light?
- 2-3 -
(3) Initial reading is not carried out (with disc)
DISC loading?
YES
NO
NO
NO
NO
NO
NO
NO
NO
Is IC201 pin14 input waveform
normal?
IC201
pin14
open close
YES
Does laser light?
CDP PCB: CN30 pin12(LD)
YES
YES
YES YES
Is signal output at tracking
output IC30 Pin 34 (CDP PCB)?
Does IC31 Pin16(LKFS)
as figure?
Disc initial reading damaged or
defective.
Disc defective.
Is rotation normal?
Is there any irregularity in
frequency?
YES
Is RF signal normal without
dropout?
NO
Check voltage in the power
supply circuitry .
Q505, R506, IC201 pin39, pin87
CDP PCB: IC34, IC35.
NO
Leaf SW contact defective.
Connector defective.
Pattern short.
NO
(A)
(B)
Does disc motor rotate?
Is RF wave output?
RF
Is tracking servo operating?
Is the lower envelope of RF
waveform flat?
Is signal output at TEO?
Is signal output at IC30
Pin21 (CDP PCB)?
IC30
(CDP PCB)
defective.
Pattern defective.
Connector defective.
Pick-up defective.
IC30
(CDP PCB)
defective.
NO
IC31(CDP PCB) defective.
- 2-4 -
(A) when laser does not light.
Is below signal “L” at IC30
Pin 37
(CDP PCB)
?
NO
NO
NO
NO
NO
NO
NO
YES
YES
Slide motor defective.
Connector defective.
YES
IC35 defective.
IC30 defective.
IC30
(CDP PCB)
defective.
Surrounding circuitry defective
TR
(CDP PCB)
defective.
Connector defective.
Laser defective
Connector defective.
Laser defective
IC30,31
(CDP PCB)
defective.
NO
NO
Reset SW defective
Connector defective.
NO
IC31 defective.
Has Pick-up returned to the
innermost position?
Does pick-up stop after having
moved to the innermost position?
IC31 Pin 16
Has laser power source returned
to the Q30
(CDP PCB)
?
(Q30 collector voltage about
1.8V)
Flow laser current?
Both voltage of Q30
(CDP PCB)
is about
1.0V?
YES
YES
YES
YES
R37
(CDP PCB)
R37
(CDP PCB)
Are data transferred from
IC31 Pin 18, 20, 27?
Is below signal output at IC31
Pin 18
(CDP PCB)
?
Are detect output input at IC30
Pin17
(CDP PCB)
?
- 2-5 -
(B) when laser light.
Do lenses move up and down?
Insert disc and
in the case of
check of initial
leading.
Is RF(HF) signal waveform
output?
NO
NO
Is signal output at focus search
terminal? IC30 Pin31
(CDP PCB)
NO
IC30
(CDP PCB)
defective.
Is signal output at IC35
Pin26, 27
(CDP PCB)
?
NO
IC30 defective.
YES
YES
YES
Actuator short.
Connector short.
IC30
(CDP PCB)
defective.
Connector short.
The waveform of RF(HF) is
below figure?
Amplitude
0.4~1.0V
NO
YES
IC30
(CDP PCB)
defective.
Q30, IC30
(CDP PCB)
surrounding circuitry
defective.
Is FOK signal output? RF(HF)
0.2V over OK.
FRSH
NO
YES
IC30
(CDP PCB)
defective.
Is FOK signal to IC201 Pin41?
(C)
FRSH
NO
YES
Pattern defective.
YES
- 2-6 -
- 2-7 -
❏
INTERNAL BLOCK DIAGRAM of ICs
■ IC201 LC723700 (Micro-processor IC)
1) PORT ASSIGNMENT
XIN 1
GND 2
VREG 3
VSSCPU 4
NC 5
NC 6
FRONT CHK 7
EJECT KEY 8
LCD SI 9
LCD SO 10
LCD CLK 11
OPTION IN 31
OPTION IN 32
OPTION OUT 33
OPTION OUT 34
OPTION OUT 35
OPTION OUT 36
NC 37
NC 38
VDD 39
GND 40
NC 41
NC 42
NC 43
NC 44
DIAGNOSTIC 45
ECE 46
EC0 47
ECL 46
POWER ON 49
NC 50
100 XOUT
99 GND
98 EO1
97 EO2
96 GNDPLL
95 FMIN
94 AMIN
93 VDDPLL
92 SUBP
91 EO3
90 FMIF
89 AMIF
88 SNS
67 ACC
86 RESET
85 SM
84 ST
83 SD
82 T PULSE DN
81 GND
80 NC
79 E-PULSE DN
78 RDS DATA
77 LEVEL METER
76 LOC/DX
75 NC
74 CDC ON
73 CDC DATA
72 CDC IN
71 RDS CLK
70 NC
69 NC
68 IF RQST
67 BAND1
66 BAND2
65 A-MUTE
64 T-MUTE
63 NC
62 NC
61 NC
60 BEEP
59 NC
58 NC
57 NC
56 NC
55 NC
54 NC
53 NC
52 NC
51 NC
XIN
TEST2
VREG
VSSCPU
SI0/PG3
SO0/PG2
SCK0/PG1
PG0
SI1/PF3
SO1/PF2
SCK1/PF1
LCD CE 12
NC 13
CD INSERT 14
NC 15
/M_SRO 16
M_D 17
W-LED 18
T-PULSE UP 19
E-PULSE UP 20
ACC_ON 21
M-CLK 22
M_DO 23
M-CS 24
MRESET 25
NC 26
NC 27
NC 28
OPTION IN 29
OPTION IN 30
PF0
SI2/PE3
SO2/PE2
SCK2/PE1
PE0
PD3
PD2
PD0/INT4
PC3
PC2
PC1
PC0
PB3
PB2
PB1
PB0
PA3
PA2
PD1/INT5
XOUT
TEST1
EO1
EO2
VSSPLL
FMIN
AMIN
VDDPLL
SUBPD (IN)
EO3 (IN)
HCTR (IN)
LCTR (IN)
/SNS
/HOLD
/RESET
PH0/ADI0
PH1/ADI1
PH2/ADI2
PH3/ADI3
VSSADC
PI3/ADI7
PJ0
PJ1
PJ2
PJ3
PK3/INT3
PL0
PL1
PL2
PL3
PM1
PM0
PM2
PM3
PN0/BEEP
PN1
PN2
PN3
PO0
PO1
PO2
PO3
PP0
PP1
PK2 INT2
PK1/INT1
PK0INT0
PI2/ADI6
PI1/ADI5
PI0/ADI4
PA1
PA0
PT1
PT0
PS3
PS2
PS1
PS0
VDDPORT
VSSPORT
PR3
PR2
PR1
PR0
PQ3
PQ2
PQ1
PQ0
PP3
PP2
LC723700
(SANYO)
- 2-8 -
2) PIN DESCRIPTION
- 2-9 -
- 2-10 -
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