LG GC260W User manual

SERVICE MANUAL
VIDEO CASSETTE
RECORDER
SERVICE MANUAL
MODELS : GC260W/GC480W/GC990W
(GC260W1/GC480W1/GC990W1)
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
GC260W GC480W GC990W
PLAY
MODELS : GC260W/GC480W/GC990W(GC260W1/GC480W1/GC990W1)
SERVICE MANUAL
P/NO : 3829RVP048E MARCH, 2004

TABLE OF CONTENTS
SECTION 1
SUMMARY
KEY TO ABBREVIATIONS . . . . . . . . . . . . . . . . 1-1
PRODUCT SAFETY SERVICING
GUIDELINES FOR VIDEO PRODUCTS . . . . . . . 1-2
SERVICING PRECAUTIONS . . . . . . . . . . . . . . . 1-3
PROPOSAL FOR APPLYING SHORT
PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
SERVICE NOTICE ON REPLACING EEPROM . .1-5
SERVICE INFORMATION FOR EEPROM
IC SETTING . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . 1-7
SECTION 2
CABINET & MAIN CHASSIS
SERVICE METHOD . . . . . . . . . . . . . . . . . . . . . 2-1
Electrical Part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
EXPLODED VIEWS . . . . . . . . . . . . . . . . . . . . . . 2-2
1. Cabinet & Main Frame Section . . . . . . . . . . . . . 2-2
2. Packing & Accessory Section . . . . . . . . . . . . . . 2-3
SECTION 3
ELECTRICAL
ELECTRICAL ADJUSTMENT POINTS
ARRANGEMENT . . . . . . . . . . . . . . . . . . . . . . . .3-1
ELECTRICAL ADJUSTMENT PROCEDURES . . 3-2
1. Servo Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
ELECTRICAL TROUBLESHOOTING GUIDE . . . 3-4
1. Power Circuit(SMPS) . . . . . . . . . . . . . . . . . . . . . 3-4
2. Servo Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
3. System & Front Panel Circuit . . . . . . . . . . . . . . .3-10
4. Y/C Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13
5. Tuner/IF Circuit . . . . . . . . . . . . . . . . . . . . . . . . .3-17
6. Hi-Fi Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-20
BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . .3-22
1. Power Block Diagram . . . . . . . . . . . . . . . . . . . .3-22
2. Tuner/IF, NICAM & A2 Block Diagram . . . . . . . .3-24
3. Y/C Block Diagram . . . . . . . . . . . . . . . . . . . . . .3-26
4. Hi-Fi Block Diagram . . . . . . . . . . . . . . . . . . . . .3-27
5. System Block Diagram . . . . . . . . . . . . . . . . . . .3-28
CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . .3-30
1. Power Circuit Diagram . . . . . . . . . . . . . . . . . . . .3-30
2. Tuner, NICAM, A2 Circuit Diagram . . . . . . . . . . .3-32
3. A/V Circuit Diagram . . . . . . . . . . . . . . . . . . . . . .3-34
4. System Circuit Diagram . . . . . . . . . . . . . . . . . . .3-36
5. Hi-Fi Circuit Diagram . . . . . . . . . . . . . . . . . . . . .3-38
• WAVEFORM . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-40
• CIRCUIT VOLTAGE CHART . . . . . . . . . . . . . . . .3-42
PRINTED CIRCUIT BOARD DIAGRAMS . . . . .3-46
1. MAIN P.C.Board (TOP VIEW) . . . . . . . . . . . . . .3-46
2. MAIN P.C.Board (BOTTOM VIEW) . . . . . . . . . .3-48
3. KEY (LEFT) P.C.Board . . . . . . . . . . . . . . . . . . .3-50
SECTION 4
MECHANISM
SECTION 5
REPLACEMENT PARTS LIST
• Replacement Part List . . . . . . . . . . . . . . . . . . . . . .5-1
NOTE) The table of contents for this section is edited
NOTE) separately.

1-1
A AC :Alternating Current
ACC :Automatic Color Control
ACSS :Automatic Channel Setting System
ADJ :Adjust
A/E :Audio Erase
AFC :Automatic Frequency Control
AFT :Automatic Fine Tuning
AGC :Automatic Gain Control
A.H.SW :Audio Head Switch
ALC :Automatic Level Control
AM :Amplitude Modulation
AMP :Amplifier
ANT :Antenna
APC :Automatic Phase Control
ASS’Y :Assembly
AUX :Auxiliary
B B :Base
BGP :Burst Gate Pulse
BPF :Bandpass Filter
BS :Brodcasting Satellite
BW or B/W :Black and White
C C :Capacitor, Chroma, Collector
CAN :Cancel
CAP :Capstan
CAP.BRK :Capstan Brake
CAP.RVS :Capstan Reverse
CATV :Cable Television
CBA :Circuit Board Assembly
CCD :Charge Coupled Device
C.CTL :Chro Control, Capstan Control
CFG :Capstan Frequency Generator
CHROMA :Chrominance
CNR :Chroma Noise Redution
COMB :Combination
Comb Filter
COMP :Comparator
Composite
Compensation
CONV :Converter
C.ROT SW :Color Rotary Switch
CS :Chip Selcet
C.SYNC :Composite Synchronization
CTL DIV :Control Divide
CUR :Current
CYL :Cylinder
D D :Drum, Digital, Diode, Drain
D.ADJ :Drum Adjust
DC :Direct Current
D.CTL :Drum Control
DEMOD :Demodulator
DET :Detector
DEV :Deviation
DHP :Double High Pass
DIGITRON :Digital Display Tube
DL :Delay line
DOC :Drop Out Compensator
DUB :Dubbing
D.V SYNC :Dummy Vertical Synchronization
E E :Emitter
EE :Electric to Eletric
EMPH :Emphasis
ENA :Enable
ENV :Envelope
EP :Extended Play
EQ :Equalizer
EXP :Expander
F F :Fuse
FB :Feed Back
FBC :Feed Back Clamp
FE :Full Erase
FG :Frequency Generator
FL :Filter
FM :Frequency Modulation
F/R :Front/Rear
FS :Frequency Synthesizer
FSC :Subcarrier Frequency
F/V :Frequency Voltage
G GEN :Generator
H H :High, Horizontal
I IC :Integrated Circuit
IF :Intermediate Frequency
INS :Insert
L L :Low, Left, Coil
LD :LED
LD VTG CTL :Loading Voltage Control
LECHA :Letter Character
L.M :Level Meter
LP :Long Play
LPF :Low Pass Filter
M MAX :Maximum
MD :Modulator
MECHA.CTL :Mechanism Control
MIC :Microphone
MIN :Minimum
MIX :Mixer, Mixing
M.M. :Monostable, Multivibrator
MMV :Mono Multi Vibrator
MOD :Modulation, Modulator
MODEM :Modulator-Demodulator
MPX :Multiplex
N NR :Noise Reduction
O OSC :Oscillator
OSD :On Screen Display
P PB :Playback
PCB :Printed Circuit Board
P.CTL :Power Control
PRE-AMP :Preamplifier
P.F :Power Failure
PG :Pulse Generator
PLL :Phase Locked Loop
PREM.DET :Premire Detect
P.P :Peak-to-Peak
PS :Phase Shift
PWM :Pulse Width Modulation
PWR CTL :Power Control
Q Q :Transistor
QH :Quasi Horizontal
QSR :Quick Setting Record
QTR :Quick Timer Record
QV :Quasi Vertical
R R :Resistor, Right
RE(or RC) :Remocon, Receiver
REC :Recording
REC S ‘H’ :Record Start ‘Hight’
REF :Reference
REG :Regulated, Regulator
REMOCON :Remote Control(unit)
RF :Radio Frequency
R/P :Record/Playback
RTC :Reel Time Counter
S S :Serial
S.ACCEL :Slow Accel
SAOP :Second Audio Program
SC :Scart, Simulcast
S.DET :Secam Detect
SH :Shift
SHARP :Sharpness
SIF :Sound Intermediate Frequency
SLD :Side Locking
S/N :Signal to Noise Ratio
SP :Standard Play
ST :Stereo
SUB :Subtract, Subcarrier
SW or S/W :Switch
SYNC :Synchronization
SYSCON :System Control
T T :Coil
TP :Test Point
TR :Transistor
TRK :Tracking
TRANS :Transformer
TU :Tuner, Take-up
U UHF :Ultra High Frequency
UNREG :Unregulated
V V :Volt, Vertical
VA :Always Voltage
VCO :Voltage Controlled Oscillator
VGC :Voltage Gain Control
VHF :Very High Frequency
V.H.SW :Video Head Switch
VISS :VHS Index Search
VPS :Video Program System
VR :Variable Resistor or Volume
V-SYNC :Vertical Synchronization
VTG :Voltage
VV :Voltage to Voltage
VXO :Voltage X-tal Oscillator
W W :Watt
WHT :White
W/O :With out
X X-TAL :Crystal
Y Y/C :Luminance/Chrominance
YNR :Luminance Noise Reduction
Z ZD :Zener Diode
SECTION1 SUMMARY
KEY TO ABBREVIATIONS

1-2
CAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY,
NEVER PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFAC-
TURER’S APPROVAL. UNAUTHORIZED MODIFICATIONS WILL NOT ONLY
VOID THE WARRANTY, BUT MAY LEAD TO YOUR BEING LIABLE FOR ANY
RESULTING PROPERTY DAMAGE OR USER INJURY.
SERVICE WORK SHOULD BE PERFORMED ONLY AFTER YOU ARE
THOROUGHLY FAMILIAR WITH ALL OF THE FOLLOWING SAFETY
CHECKS AND SERVICING GUIDELINES. TO DO OTHERWISE,
INCREASES THE RISK OF POTENTIAL HAZARDS AND INJURY TO THE
USER.
WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR PROTEC-
TION FROM A.C. LINE SHOCK.
SAFETY CHECKS
AFTER THE ORIGINAL SERVICE PROBLEM HAS BEEN CORRCTED. A
CHECK SHOULD BE MADE OF THE FOLLOWING.
SUBJECT : FIRE & SHOCK HAZARD
1. BE SURE THAT ALL COMPONENTS ARE POSITIONED IN SUCH A WAY
AS TO AVOID POSSIBILITY OF ADJACENT COMPONENT SHORTS.
THIS IS ESPECIALLY IMPORTANT ON THOSE MODULES WHICH ARE
TRANSPORTED TO AND FROM THE REPAIR SHOP.
2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE DEVICES
SUCH AS INSULATORS, BARRIERS, COVERS, SHIELDS, STRAIN
RELIEFS, POWER SUPPLY CORDS, AND OTHER HARDWARE HAVE
BEEN REINSTALLED PER ORIGINAL DESIGN. BE SURE THAT THE
SAFETY PURPOSE OF THE POLARIZED LINE PLUG HAS NOT BEEN
DEFEATED.
3. SOLDERING MUST BE INSPECTED TO DISCOVER POSSIBLE COLD
SOLDER JOINTS, SOLDER SPLASHES OR SHARP SOLDER POINTS.
BE CERTAIN TO REMOVE ALL LOOSE FOREIGN PARTICLES.
4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE OR DETERIORATION
TO PARTS AND COMPONENTS. FOR FRAYED LEADS, DAMAGED
INSULATION (INCLUDING A.C. CORD). AND REPLACE IF NECESSARY
FOLLOW ORIGINAL LAYOUT, LEAD LENGTH AND DRESS.
5. NO LEAD OR COMPONENT SHOULD TOUCH A RECIVING TUBE OR
A RESISTOR RATED AT 1 WATT OR MORE. LEAD TENSION AROUND
PROTRUNING METAL SURFACES MUST BE AVOIDED.
6. ALL CRITICAL COMPONENTS SUCH AS FUSES, FLAMEPROOF
RESISTORS, CAPACITORS, ETC. MUST BE REPLACED WITH EXACT
FACTORY TYPES, DO NOT USE REPLACEMENT COMPONENTS
OTHER THAN THOSE SPECIFIED OR MAKE UNRECOMMENDED CIR-
CUIT MODIFICATIONS.
7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN A.C.
LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OF THE CABI-
NET, (THE CHANNEL SELECTOR KNOB, ANTENNA TERMINALS. HAN-
DLE AND SCREWS) TO BE SURE THE SET IS SAFE TO OPERATE
WITHOUT DANGER OF ELECTRICAL SHOCK. DO NOT USE A LINE
ISOLATION TRANSFORMER DURING THIS TEST USE AN A.C. VOLT-
METER, HAVING 5000 OHMS PER VOLT OR MORE SENSITIVITY, IN
THE FOLLOWING MANNER; CONNECT A 1500 OHM 10 WATT RESIS-
TOR, PARALLELED BY A .15 MFD. 150.V A.C TYPE CAPACITOR
BETWEEN A KNOWN GOOD EARTH GROUND (WATER PIPE, CON-
DUIT, ETC.) AND THE EXPOSED METALLIC PARTS, ONE AT A TIME.
MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION OF 1500
OHM RESISTOR AND .15 MFD CAPACITOR. REVERSE THE A.C. PLUG
AND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED
METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED 75
VOLTS R.M.S. THIS CORRESPONDS TO 0.5 MILLIAMP A.C ANY
VALUE EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL SHOCK
HAZARD AND MUST BE CORRECTED IMMEDIATELY.
SUBJECT: 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 MAG-
NITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.
THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIAN-
GLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO
THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN
SERVICE LITERATURE.
SUBJECT : X-RADIATION
1. BE SURE PROCEDURES AND INSTRUCTIONS TO ALL SERVICE PER-
SONNEL COVER THE SUBJECT OF X-RADIATION. THE ONLY POTEN-
TIAL SOURCE OF X-RAYS IN CURRENT T.V. RECEIVERS IS THE PIC-
TURE TUBE. HOWEVER, THIS TUBE DOES NOT EMIT X-RAYS WHEN
THE HIGH VOLTAGE IS AT THE FACTORY SPECIFIED LEVEL. THE
PROPER VALUE IS GIVEN IN THE APPLICABLE SCHEMATIC. OPERA-
TION AT HIGHER VOLTAGES MAY CAUSE A FAILURE OF THE PIC-
TURE TUBE OR HIGH VOLTAGE SUPPLY AND, UNDER CERTAIN CIR-
CUMSTANCES, MAY PRODUCE RADIATION IN EXCESS OF DESIR-
ABLE LEVELS.
2. ONLY FACTORY SPECIFIED C.R.T. ANODE CONNECTORS MUST BE
USED. DEGAUSSING SHIELDS ALSO SERVE AS X-RAY SHIELD IN
COLOR SETS, ALWAYS RE-INSTALL THEM.
3. IT IS ESSNTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE AN
ACCURATE AND RELIABLE HIGH VOLTAGE METER. THE CALIBRA
TION OF THE METER SHOULD BE CHECKED PERIODICALLY
AGAINST A REFERENCE STANDARD, SUCH AS THE ONE AVAILABLE
AT YOUR DISTRIBUTOR.
4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLY
THERE IS NO POSSIBILITY OF AN X-RADIATION PROBLEM. EVERY
TIME A COLOR CHASSIS IS SERVICED. THE BRIGHTNESS SHOULD
BE RUN UP AND DOWN WHILE MONITORING THE HIGH VOLTAGE
WITH A METER TO BE CERTAIN THAT THE HIGH VOLTAGE DOES
NOT EXCEED THE SPECIFIED VALUE AND THAT IT IS REGULATING
CORRECTLY, WE SUGGEST THAT YOU AND YOUR SERVICE ORGA-
NIZATION REVIEW TEST PROCEDURES SO THAT VOLTAGE REGU-
LATION IS ALWAYS CHECKED AS A STANDARD SERVICING PROCE-
DURE. AND THAT THE HIGH VOLTAGE READING BE RECORDER ON
EACH CUSTOMER’S INVOICE.
5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS IN
A PRODUCT WITH A PROBLEM OF EXCESSIVE HIGH VOLTAGE,
AVOID BEING UNNECESSARILY CLOSE TO THE PICTURE TUBE AND
THE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCT
LONGER THAN IS NECESSARY TO LOCATE THE CAUSE OF EXCES
SIVE VOLTAGE.
6. REFER TO HV. B+ AND SHUTDOWN ADJUSTMENT PROCEDURES
DESCRIBED IN THE APPROPRIATE SCHEMATIC AND DIAGRAMS
(WHERE USED).
SUBJECT: IMPLOSION
1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTE
GRAL IMPLOSION PROTECTION SYSTEM, BUT CARE SHOULD BE
TAKEN TO AVOID DAMAGE DURING INSTALLATION, AVOID
SCRATCHING THE TUBE. IF SCRATCHED REPLACE IT.
2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES.
SUBJECT : TIPS ON PROPER INSTALLATION
1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS, CUBBY-
HOLE OR CLOSELY FITTING SHELF SPACE. OVER OR CLOSE TO
HEAT DUCT, OR IN THE PATH OF HEATED AIR FLOW.
2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS: OUTDOOR PATIO
INSTALLATIONS WHERE DEW IS A FACTOR, NEAR STEAM RADIA-
TORS WHERE STEAM LEAKAGE IS A FACTOR, ETC.
3. AVOID PALCEMENT WHERE DRAPERIES MAY OBSTRUCT REAR
VENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DEC-
ORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT
OBSTRUCT VENTILATION.
4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMER-
CIAL MOUNTING KIT. MUST FOLLOW THE FACTORY APPROVED
MOUNTING INSTRUCTIONS A PRODUCT MOUNTED TO A SHELF OR
PLATFORM MUST RETAIN ITS ORIGINAL FEET (OR THE EQUIVALENT
THICKNESS IN SPACERS) TO PROVIDE ADEQUATE AIR FLOW
ACROSS THE BOTTOM, BOLTS OR SCREWS USED FOR FASTENERS
MUST NOT TOUCH ANY PARTS OR WIRING. PERFORM LEAKAGE
TEST ON CUSTOMIZED INSTALLATIONS.
5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A PRODUCT ON
SLOPING SHELF OR A TILTED POSITION, UNLESS THE PRODUCT IS
PROPERLY SECURED.
6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE ON ITS
MOUNTING TO THE CART. CAUTION THE CUSTOMER ON THE HAZ-
ARDS OF TRYING TO ROLL A CART WITH SMALL CASTERS ACROSS
THRESHOLDS OR DEEP PILE CARPETS.
7. CAUTION CUSTOMERS AGAINST THE USE OF A CART OR STAND
WHICH HAS NOT BEEN LISTED BY UNDERWRITERS LABORATORIES,
INC. FOR USE WITH THEIR SPECIFIC MODEL OF TELEVISION
RECEIVER OR GENERICALLY APPROVED FOR USE WITH T.V.’S OF
THE SAME OR LARGER SCREEN SIZE.
8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION CORDS,
EXPLAIN THAT A FOREST OF EXTENSIONS SPROUTING FROM A SIN-
GLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TO
HOME AND FAMILY.
PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS
A.C. VOLTMETER
GOOD EARTH GROUND
SUCH AS THE WATER
PIPE. CONDUIT. ETC
PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

1-3
SERVICING PRECAUTIONS
CAUTION : Before servicing the VCR covered by this service
data and its supplements and addends, read and follow the
SAFETY PRECAUTIONS. NOTE : if unforeseen circum-
stances create conflict between the following servicing pre-
cautions and any of the safety precautions in this publica-
tions, always follow the safety precautions.
Remembers Safety First:
General Servicing Precautions
1. Always unplug the VCR AC power cord from the AC
power source before:
(1) Removing or reinstalling any component, circuit board,
module, or any other assembly.
(2) Disconnection or reconnecting any internal electrical
plug or other electrical connection.
(3) Connecting a test substitute in parallel with an elec-
trolytic capacitor.
Caution : A wrong part substitution or incorrect
polarity installation of electrolytic capacitors may result
in an explosion hazard.
2. Do not spray chemicals on or near this VCR or any of
its assemblies.
3. Unless specified otherwise in this service data, clean
electrical contacts by applying an appropriate contact
cleaning solution to the contacts with a pipe cleaner,
cotton-tipped swab, or comparable soft applicator.
Unless specified otherwise in this service data, lubrication
of contacts is not required.
4. Do not defeat any plug/socket B+ voltage interlocks with
whitch instruments covered by this service manual might
be equipped.
5. Do not apply AC power to this VCR and/or any of its
electrical assemblies unless all solid-state device heat
sinks are cerrectly installed.
6. Always connect test instrument ground lead to the
appropriate ground before connection the test instrument
positive lead. Always remove the test instrument ground
lead last.
Insulation Checking Procedure
Disconnect the attachment plug from the AC outlet and turn
the power on. Connect an insulation resistance meter(500V)
to the blades of the attachment plug. The insulation resis-
tance between each blade of the attachment plug and acces-
sible conductive parts (Note 1) should be more than 1M-
ohm.
Note 1 : Accessible Conductive Parts including Metal pan-
els, Input terminals, Earphone jacks, etc.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged
easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples of
typical ES 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 compo-
nent or semiconductor-equipped assembly, drain off any
electrostatic charge on your body by touching a known
earth ground. Alternatively, obtain and wear a commer-
cially 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 ES
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 grouned-tip soldering iron to solder or unsolder
ES devices.
4. Use only an anti-static solder removal device. Some
solder removal devices not classified a “anti-static” can
generate electrical charges sufficient to damage ES
devices.
5. Do not use freon-propelled chemicals. These can
generate electrical charge sufficient to damage ES
devices.
6. Do not remove a replacement ES device from its protec
tive package until immediately before you are ready to
install it. (Most replacement ES 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 ES 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 ES devices. (Normally harmless motion such
as the brushing together of your clothes fabric or the lifting
of your foot from a carpeted floor can generate static elec-
tricity sufficient to damage an ES device.)

1-4
• The Contents of Examination
As all the IC that is applied to VCR is controlled by IIC, mutual communication, if Vcc of IC is short or open
with detecting ‘Acknowledge’ data of the specific IC according to each power(5V, 5VT) µ-COM gets unable to
detect ‘ACK’ data.
µ-COM regards this case as abnormal one and if it can’t detect ‘ACK’ data for a certain time(3.5 sec) the sig-
nal of ‘Power Control’ and ‘Timer Control’ are switched to ‘Low’. As a result POWER Switching TR is kept from
generating heat and fire.
• POWER for each IC
S/ 5V POWER SECAM IC
Series 5VT POWER AVCP IC
P/Y/I 5V POWER Modulator
Series 5VT POWER AVCP IC
*Short protection off mode : DJ01 Diode in
PROPOSAL FOR APPLYING SHORT PROTECTION
IIC BUS
5VT SW POWER
CONTROL
MASTER
TIMER
CONTROL
5VT SW
SLAVE with 5V
SLAVE with 5V
5.3VA
Timer Control
AVCP IC
TUNER
Conception
BLOCK Diagram
5.2V 5.2VT
• IC to detect ‘ACK’ data is selected as below because IC is different in accordance to region and option
5.3VA
Power Control
Modulator
Hi-Fi IC
NICAM IC
SECAM IC

1-5
In case that defective EEPROM of PAL models is replaced, to operate these sets from the initial state MP KEY
must be repaired as well before delivering to the customer.
If MP KEY isn’t repaired the setting of RF OUT channel or LANGUAGE might be different from that for cus-
tormer’s country.
•MP KEY : In case of PAL VCR if holding the REC button on the front panel and the CLEAR button on the
remote control handset for 5 ~ 7 seconds with power being switch all and no tapes,
OK is displayed at FLD for FLD models and LED becomes on for LED CLOCK models.
This is the state that initializing EEPROM is finished.
(In case of PAL VCP if holding the REC button on the front panel and the MENU button on the
remote control handset for 5 ~ 7 seconds with power being off and no tapes, All the LED DOTs
become on. This is the state that initializing EEPROM is finished.)
•MP KEY's function : MP KEY sets EEPROM's data up to the initial state.
SERVICE NOTICE ON REPLACING EEPROM
TIMER
AM
REC
VCR
OK
• FLD MODEL:
MP KEY “OK”
• LED CLOCK MODEL:
MP KEY Switch all on a Light
• LED DOT MODEL:
MP KEY Switch all on a Light

1-6
SERVICE INFORMATION FOR EEPROM IC SETTING
MODEL NAME HEX BINARY
GC260W OPTION1 10 00000000
OPTION2 90 00000000
OPTION3 06 00000000
GC480W OPTION1 10 00000000
OPTION2 81 00000000
OPTION3 06 00000000
GC990W OPTION1 10 00000000
OPTION2 A1 00000000
OPTION3 0E 00000000
WR : OK I : EXIT MOVE : F G
EDIT : DE
1. DETECT NEW EEPROM (OPTION EDIT SCREEN)
- Eeprom EDIT screen automatically appears if
replacing Eeprom.
• Setup option data using the cursor Up/Down key
of a remote control.
(Setup upon BOM depending on OPT1~OPT3
model)
• Since an initial remote control is set to LG for LG
model, appropriately set optional data using the
cursor Up/Down key.
2. EEPROM WRITED COMPLETE SCREEN
- Writes data on EEPROM by using REMOCON
"OK".
- If completing the option data screen with a menu
key, Powering Off is automatically done and the
option edit screen is arranged.
3. PG ADJUST
a) Insert the PAL SP Test Tape and play.
Note - Adjust the distance of X, pressing the
Tracking(+) or Tracking(-) when the “ATR” is
blink after the
PAL SP Test Tape is inserted.
b) Press “Play” key on set and “0” key on
Remocon.(Then check the blink “TRK OK” (Hi-Fi
Model), “ALL LIGHT”(MONO Model) on CLK/LED
-TRK is a Initial)
c) Press “Play” key on set and “0” key on Remocon
again.(Then check the blink “PG NG > PG OK”
on CLK/LED(Hi-Fi Model), Then check the blink
“PG waveform” on oscilloscope(MONO Model)).
4. EEPROM INITIAL
- SETUP is displayed in the field if pressing the
FRONT REC KEY with the remocon number
"CLEAR" key pressed in the status of powering
Off.
- AUTO SEARCH is done since the initial screen of
ACMS is serviced if powering On.
- Check basic operation (PLAY/RECORD...)
EEPROM option code No. setting EEPROM option code No. setting procedure
NAME HEX BINARY
OPT1 00 00000000
OPT2 00 00000000
OPT3 00 00000000
WR : OK I : EXIT MOVE : F G
EDIT : DE
MASKROM : R00
EEPROM : R00 LG CODE

1-7
SPECIFICATIONS
General
Power 110-240V~, 50/60Hz
Power consumption Approx. 12 Watts
Video Head System Double azimuth 4 heads, helical scanning (EC-530W)
Rotary 2 heads, helical scanning (EC-330W)
Tape speed PAL: 23.39 mm/sec (SP mode) 11.69 mm/sec (LP mode)
NTSC: 33.35 mm/sec (SP mode) 11.12 mm/sec (LP mode)
Tape Format Tape width 12.7mm (0.5 inch)
Max. recording time PAL: 4 hours (SP mode, E-240 Tape)
8 hours (LP mode, E-240 Tape)
NTSC: 2 hours (SP mode, T-120 Tape)
8 hours (EP mode, T-160 Tape)
Rewind time Approx. 65 (±10) secs (E-180 tape)
Dimensions 360 x 82 x 230mm (W x H x D)
Weight 2.87 kg
Operating temperature 5º C - 35º C
Operating humidity Less than 80%
Timer 24 hours display type
Video
Television system CCIR standard (625 lines, 50 fields)
PAL/SECAM colour signal
Recording format PAL/MESECAM/NTSC 3.58/NTCS 4.43
RF reception PAL SECAM (B/G, D/K, I/I)
RF OUT PAL G/K/I
Input level VIDEO IN (RCA) 1.0 Vp-p, 75 Ohm unbalanced
Output level VIDEO OUT (RCA) 1.0 Vp-p, 75 Ohm unbalanced
Signal to noise ratio More than 43 dBm
RF modulator UHF channel 22-68 (Adjustable)
Audio
Input level AUDIO IN (RCA) - 6.0 dBm, more than 47 kohms
Output level AUDIO OUT (RCA) - 6.0 dBm, less than 1 kohms
Track Mono track
Frequency response 100 Hz - 10 kHz (-6/+3 dBm)
Signal to noise ratio More than 43 dB

2-1
SECTION2 CABINET & MAIN FRAME
Fig.2-1
SERVICE METHOD
(1) Disassembly Flow
(Positioned Upside Down)
(2) Re-assembly Flow for service like Fig. 2-1
(3) To check and replace Electrical parts
1Disassemble the unit according to
No.1) Disassembly Flow.
2Re-assemble the unit according to
No.2) Re-assembly Flow.
3Place the unit like Fig. 2-1
4 Check and replace Electrical parts.
NOTE :
1Insert Video Cassette Tape inversely like Fig. 2-1
to check and replace defective parts.
2In disassembling and reassembling, be careful not
to damaged CST switch.
Top Case
Bottom Cover
Front Panel
Housing & Deck
Assembly
Main C.B.A
LED C.B.A
LED C.B.A
Main C.B.A
Housing & Deck
Assembly
Housing y Mecanismo
Cassette Tape
(Upside Down)
C.B.A Princioal

2-2
EXPLODED VIEWS
1. Cabinet and Main Frame Section
283
280
284
261
260
A00
457
457
462
462
250
300
A43
330
452
320
A46
A44
323
275
A42
A
5
4
3
2
1
BCD
NOTE) Refer to “SECTION 5 REPLACEMENT
PARTS LIST” in order to look for the
part number of each part.
_ OPTIONAL PARTS

2.Packing Accessory Section
OPTIONAL PARTS
CABLE, COAXIAL
(Optional parts)
810
BATTERY808
806
PLUG ASS'Y 2WAY
(Optional parts)
812
PLUG ASS'Y 1WAY
CABLE ASS'Y RF (Optional parts)
811
REMOCON900
PACKING (RF)803
PACKING (LF)803
BOX CARTON802
BAG. SOFR SHEET804
INSTRUCTION MANUAL801
NOTE) Refer to “SECTION REPLACEMENT PARTS LIST
NOTE) in order to look for the part number of each part.
2-3

3-1
Hi-Fi
AVCP
U-COM
S
M
P
SSYSTEM
A/V
DECK CNT.
A/V JACK T
U
N
E
R
TUNER &
MODULATOR
SMPS
LED
DRIVE
CLK/DOT DISP
KEY
BOARD(L) KEY BOARD(R)
3/4 CH SWITCH
: Measurement point
: Adjustment point
SECTION 3 ELECTRICAL
ELECTRICAL ADJUSTMENT POINTS ARRANGEMENT

3-2
ELECTRICAL ADJUSTMENT PROCEDURES
1. Servo Adjustment
1) PG Adjustment
• Test Equipment
• Adjustment And Specification
a) OSCILLOSCOPE
b) PAL TEST TAPE (VHS SP)
c) JIG REMOCON (AUTO PG SETTING)
MODE
PLAY
• Adjustment Procedure
a) Insert the PAL SP Test Tape and play.
Note - Adjust the distance of X, pressing the Tracking(+) or Tracking(-) when the “ATR” is blink after the
PAL SP Test Tape is inserted.
b) Press “Play” key on set and “0” key on Remocon.(Then check the blink “TRK OK” (Hi-Fi Model), “ALL
LIGHT”(MONO Model) on CLK/LED
-TRK is a Initial)
c) Press “Play” key on set and “0” key on Remocon again.(Then check the blink “PG NG > PG OK” on
CLK/LED(Hi-Fi Model), Then check the blink “PG waveform” on oscilloscope(MONO Model)).
• Check the PG
a) Connect the CH1 of the oscilloscope to the H/SW and CD2 to the Video out for the VCR.
b) Trigger the mixed Video Signal of CH2 to the CH1 H/SW(W714, W715), and then check the distance
(time difference), which is from the selected A(B) Head point of the H/SW(W714, W715) signal to the
starting point of the vertical synchronized signal, to 6.5H ± 0.5H (416µs, 1H=64.0µs).
• CONNECTION
V.Out
H/SW(W714, W715) 6.5 ± 0.5H
MEASUREMENT POINT ADJUSTMENT POINT SPECIFICATION
V.Out
H/SW(W714,W715)
OSCILLOSCOPE
CH1 CH2
V.outH/SW
(W714, W715)

3-3
ELECTRICAL ADJUSTMENT PROCEDURES
• WAVEFORM
• Attension and Reference
a) The PG checking must do when RF Level is Maximum and SERVO system is Locking (MTR MODE)
b) V.H/SW Level is 2Vpp.
H/SW
Composite
VIDEO
6.5H(416us)

3-4
ELECTRICAL TROUBLESHOOTING GUIDE
1. Power Circuit(SMPS)
(1) No 5.3VA.
No 5.3VA.
Is the F101 normal?
Is the BD101 normal?
Is the R101 normal?
Does the oscillation waveform appear at
the IC101 Pin 7?
Is there DC voltage at the IC101 Pin 4?
Is there about 2.5V at the IC103 Vref ?
Is the D106 normal?
Check the Main PCB 5.3VA Line short?
Replace the F101
(Use the same Fuse).
Replace the BD101.
Replace the R101.
Is Vcc(about 13~15V) permittable at the
IC101 Pin 3?
Check or Replace the D103.
Replace the IC102.
Replace the IC103.
Replace the D106.
NO
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO

3-5
Is the D109 normal? Replace the D109.
Check 12VA Line of the Main PCB short.
YES
YES
No 12VA.
Does 5.3VA work normally? Check whether 5.3VA is out of order.
YES
NO
NO
7. Power Circuit(SMPS)
(2) No 12VA.(Capstan)
(3) No 12V (Hi-Fi, Buffer)
Is Voltage(about 13V) put into the
Q152(B)?
Check or Replace the Q152.
YES
YES
No 12VA.
Is Vcc(about 12V) put into the Q152(E)? Replace the Peripheral Circuitry of ZD152.
YES
NO

7. Power Circuit(SMPS)
(4) No 5V
Is about 4.7V put into the
Q155(Q157) Base?
Check the Q156
whether it works normally.
Check or Replace the Q155(Q157).
YES
YES
No 5V.
Is the Q156 Base “H”?
Is 5.3VA put into the Q155(Q157)
collector?
Check the µ-com Control.
YES
YES
NO
NO
3-6

3-7
2. Servo Circuit
Unstable Video in PB
Mode.
Does the on screen noise
level change periodically?
Do CTL pulses appear at
IC501 pin 97?
Does the CFG divide
waveform appear at IC501
pin 87?
Do the CTL pulses move
when TRK is operated?
Replace IC501.
Does the Video Envelope
waveform appear at IC501
Pin 9?
NO
YES
YES
YES
YES
YES
A.
Is the height of the CTL
Head adjusted correctly?
NO
Replace IC501.
NO
Check Y/C Block.
NO
Adjust the CTL Head.