LG EC290W User manual

SERVICE MANUAL
VIDEO CASSETTE
RECORDER
SERVICE MANUAL
MODELS : EC290W/EC290SW/EC470W/
EC490SW/EC970W/EC990SW
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
EC470W/970W EC290W/290SW/490SW/990SW
MODELS : EC290W/EC290SW/EC470W/EC490SW/EC970W/EC990SWSERVICE MANUAL

TABLE OF CONTENTS
SECTION 1
SUMMARY
KEY TO ABBREVIATIONS . . . . . . . . . . . . . . . . 1-1
IMPORTANT SAFETY PRECAUTIONS . . . . . . . . . . 1-2
• Precautions During Servicing
SAFETY CHECK AFTER SERVICING . . . . . . . . 1-3
• Insulation resistance test
• Dielectric strength test
• Clearance distance
• Leakage current test
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 . . . . . . . . . . . . . . . . . . . . . . . .3-46
2. KEY (LEFT) P.C.Board . . . . . . . . . . . . . . . . . . .3-48
SECTION 4
MECHANISM
SECTION 5
REPLACEMENT PARTS LIST
• Mechanical Section . . . . . . . . . . . . . . . . . . . . . . . .5-1
• Electrical Section . . . . . . . . . . . . . . . . . . . . . . . . .5-3
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
Prior to shipment from the factory, the products are strictly inspected to conform with the recognized product
safety and electrical codes of the countries in which they are to be sold. However, in order to maintain such com-
pliance, it is equally important to implement the following precautions when a set is being serviced.
• Precautions during Servicing
1. Locations requiring special caution are denoted by labels and inscriptions on the cabinet, chassis and
certain parts of the product. When performing service, be sure to read and comply with these and other
cautionary notices appearing in the operation and service manuals.
2. Parts identified by the symbol and shaded (
Y ) parts are critical for safety.
Replace only with specified part numbers.
Note : Parts in this category also include those specified to comply with X-ray emission standards for
products using cathode ray tubes and those specified for compliance with various regulations
regarding spurious radiation emission.
3. Use Specified internal wiring. Note especially:
1) Double insulated wires
2) High voltage leads
4. Use specified insulating materials for hazardous live parts. Note especially:
1) Insulation Tape
2) PVC tubing
3) Spacers
4) Insulation sheets for transistor
5. Observe that wires do not contact heat producing
parts (heatsinks, oxide metal film resistors, fusible
resistors, etc.)
6. Check that replaced wires do not contact sharp edged
or pointed parts.
7. 1) When a power cord has been replaced, check
that A mark is made on the cord, under strain,
near the aperture, and the flexible cord is
subjected 100 times to a pull of 40N for a duration
of 1 second each.
2) During the test, the cord shall not be displaced by
more than 2mm
8. Also check areas surrounding repaired locations.
9. The internal wiring is secured so as not to approach the heating parts and high voltage parts by its shape.
So, these wires must be restored to its former state.
IMPORTANT SAFETY PRECAUTIONS
Fig. 1
Power Code
or Power Cord

1-3
Fig. 3
SAFETY CHECK AFTER SERVICING
Examine the area surrounding the repaired location for damage or deterioration. Observe that screws, parts and
wires have been returned to original positions. Afterwards, perform the following tests and confirm the specified
values in order to verify compliance with safety standards.
• Insulation resistance test
confirm the specified insulation resistance or greater between power cord plug prongs and externally exposed
parts of the set (RF terminals, antenna terminals, video and audio input and output terminals, incrophone jacks,
earphone jacks, etc.) See table below.
• Dielectric strength test
Confirm specified dielectric strength or greater between power cord prongs and exposed accessible parts of
the set (RF terminals, antenna terminals, video and
audio input and output terminals, incrophone jacks,
earphone jacks, etc.) See table below.
• Clearance distance
When replacing primary circuit components, confirm
specified clearance distance (d), (d') between sol-
dered terminals, and between terminals and sur-
rounding metallic parts. See table below.
Table 1 : Ratings for selected areas
* Class II model only.
Note. This table is unofficial and for reference only. Be sure to confirm the precise values for your particular
country and locality.
• Leakage Current test
Confirm specified or lower leakage current between B(earth ground, power cord plug prongs) and externally
exposed accessible parts (RF terminals, antenna terminals, video and audio input and output terminals, micro-
phone jacks, earphone jacks, etc.)
Measuring Method: (Power ON)
Insert load Z between B(earth ground, power cord
plug prongs) and exposed accessible parts. Use an
AC voltmeter to measure across both terminals of
load Z. See figure and following table.
Table 2:Leakage current ratings for selected areas.
Note. This table is for IEC member only. Be sure to confirm the precise values for your particular country and
Note. locality.
Chassis
d
a
Primary circuit terminals
Exposed
accessible
part Z
Load AC Voltmeter
Earth Ground,
Power cord plug prongs
B
Fig. 2
AC Line Voltage
AC Line Voltage
100 to 130 V
200 to 240 V
*100 to 130 V
*200 to 240 V
Europe
Australia
Europe
Australia
Other terminals
Antenna earth
terminals
i E0.7m A peak
i E2m A DC
i E0.7m A peak
i E2m A DC
F10 MΩ/500 V DC 4kV 1 minute
F6mm(d)
F8mm(d)
(a Power cord)
Region Load Z Leakage Current(i) Earth Ground
(B) to :
Region Insulation
Resistance
Dielectric
Strength Clearance
Distance(d),(d)
2kΩ
50kΩ

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

1-7
SPECIFICATIONS
General
Power : 100~240V, 50/60Hz
Power consumption : Approx. 12 watts(Energy Saving mode : 3 watts)
Video Head system : Rotary 2heads, helical scanning system
(2HD Model Only)
Double azimuth 4 heads, helical scanning system
(4HD MONO, 4HD Hi-Fi Model Only)
Tape speed : 23.39 mm/sec (SP mode)11.69 mm/sec(LP mode)
Tape format : Tape width 1/2”(12.7 mm high density VHS tape)
Maximum recording time : 4 hours in SP mode/8 hours in LP mode (with E-240 tape)
Rewind time : Approx. 150 sec. (with E-180 tape)
Dimensions (W X H X D) : 360 x 94.5 x 230 mm
Weight : 9.0 lbs. (4.0 kg)
Operating temperature : 41°F-95°F (5°C-35°C)
Operating humidity : Less than 80%
Timer : 24 hours display type
Video
Input level : VIDEO IN (RCA type)
1.0 Vp-p, 75 ohm, unbalanced
Output level : VIDEO OUT (RCA type)
1.0 Vp-p, 75 ohm, unbalanced
Signal to noise ratio : More than 43 dBm
RF Modulator : UHF 28~68(Adjustable)
Audio
Input level : AUDIO IN (RCA type)
-6.0dBm, more than 47kΩ
Output level : AUDIO OUT (RCA type)
-6.0 dBm, less than 1kΩ
Track Mono track & Hi-Fi track
Frequency response : Normal : 100 Hz - 10 kHz(-6/+3 dB)
Hi-Fi : 20 Hz - 20 kHz(3-/+3 dB)
Signal to noise ratio : Normal : More than 43 dBm(at SP mode)
Dynamic range : Hi-Fi : More than 70 dBm(at SP mode)
Hi-Fi : More than 85 dBm(at SP mode)
•Design and specifications are subject to change without notice.
:Hi-Fi Model only

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
457
A00
464
462
462
250
300
A43
330
452
457
320
A46
A42
A49
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 SET ASS'Y
(Optional parts)
810
BATTERY808
806
PLUG ASS'Y 2WAY
(Optional parts)
812
PLUG ASS'Y 1WAY
(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
S
SYSTEM
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 the Auto PG KEY on JIG Remocon(1’st) or 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 the Auto PG Key on JIG Remocon again (2’nd) or 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.out
H/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.

3-8
Drum Motor stopped.
Does 12V appear at PMC01 PIN8?
Does Drum CTL signal appear at PMC01
PIN12?
Check Connector and Drum Motor Ass’y.
Check the Components and foil Pattern
between IC501 Pin 76 and PMC01
Pin 12 for shorts.
Does the Drum PWM waveform
appear at IC501 Pin 76?
Check the Components and foil Pattern
Connected to IC501 Pin 76 PMC01
Pin 12 for shorts.
Do DPG/FG Pulses appear at IC501
Pin 90?
B.
NO
NO
NO
NO
Check Power.
Does Drum PWM appear at IC501
Pin 76?
Do DPG/FG Pulses appear at PMC01
Pin 11?
Check Drum Monitor Ass’y.
Check the Components and foil pattern
between PMC01 Pin 11 and IC501
Pin 90 for shorts.
Replace IC501.
YES
YES
YES
YES
YES
NO
NO

3-9
Capstan Motor Stopped.
Check Power.
Does PWM wave appear at IC501
Pin 77?
Does the CFG signal appear at PMC01
Pin 1?
Check Capstan Motor Ass’y.
Check Components and foil patterns
between PMC01 Pin 1 and IC501
Pin 87 for shorts.
Replace IC501.
Does 12VA appear at PMC01 Pin 2?
Does 2.8V appear at PMC01 Pin 9?
Check Connector and Capstan
Motor Ass’y.
Check the Components and foil Patterns
Connected between IC501 Pin 77 and
PMC01 Pin 9 for shorts.
Does the CFG signal appear at IC501
Pin 87?
Does Capstan PWM appear at IC501
Pin 77?
Check the components and foil pattern
connected between IC501 Pin 77 and
PMC01 Pin 9 for shorts
C.
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
NO