Daewoo DV-K884N-SJ User manual

Service Manual
Model : DV-K884N-SJ
K884N-JJ
K884N-SG
K784N-SJ
K784N-JJ
K784N-SG
K884NY-SJ/M
K884NZ-SJ/M
K884NZ-SG/M
DV-K804N-SJ
DAEWOO ELECTRONICS CO., LTD
OVERSEAS SERVICE DEPT.
Service Manual
DAEWOO ELECTRONICS CO., LTD
OVERSEAS SERVICE DEPT.
DEAWOO ELECTRONICS CO., LTD
686, AHYEON-DONG MAPOGU,
SEOUL, KOREA.
C.P.O. BOX 8003 SEOUL KOREA
TELEX: DWELEC K28177-8
CABLE:"DAEWOOELEC"
FAX: [phone]
TEL: [phone], 8114
http://www.dwe.daewoo.co.kr
S031GBA PRINTED DATE: OCT. 1997
✔ Caution
: In this Manual, some parts can be changed for improving, their
performance without notice in the parts list. So, if you need the
latest parts information,please refer to PPL(Parts Price List) in
Service Information Center (http://svc.dwe.co.kr).

Power Input: 110~250 Volts AC50/60Hz ¡
120 Volts AC 60Hz ¡¡
Power Consumption: 19 Watts (4-head Hi-Fi)
Operating Temperature: 5 degree C to 40 degree C
(41 degree F to 104 degree F)
Storage Temperature: -30 degree C to 65 degree C
(-22 degree F to 149 degree F)
Weight: 3.8 kg
Dimensions: 360mm Wide X 90mm High X
278mm Deep
Recording System:
4-head Hi Fi: Four video record/playback
heads
Rotary helical scan/luma: FM
recording/chroma: converted
subcarrier phase shifted recording
Two audio record/playback
heads
Rotary helical scan, 2 channels
FM recording
¡:
K884NY-SJ/M, K884NZ-SJ/M, K884NZ-SG/M
¡: K884N-SJ, K884N-JJ, K884N-SG, K784N-SJ,
K784N-JJ, K784N-SG, K804N-SJ
Video Signal: EIA standard; NTSC color
Antenna: 75 ohm input impedance
Video Signal Level: 1Vp-p (140 IRE standard)
Audio Input Impedance: 47k ohms
Audio Output
Impedance: Less than 1.5k ohm
Tape Speed: SP: 33.35mm/sec.
SLP: 11.13mm/sec
Maximum Recording Time: T-60: 3 hours/SLP mode
T120: 6 hours/SLP mode
Fast Forward/Rewind Time: 3 minutes (T-120 tape)
Tuning System: Auto Program/Cable
Compatible/Frequency
Synthesis (FS)
Note: Specifications are subject to change without notice.
1
SPECIFICATIONS
Cleaning and Lubrication
A. Cleaning the Tape Transport System
The following parts should be cleaned after every 500 hours
of use.
• TENSION POLE
• S-GUIDE POST
• FE HEAD
• S GUIDE ROLLER
• S-SLANT POLE
• VIDEO HEAD/DRUM
• T-SLANT POLE
• T-GUIDE ROLLER
• AC HEAD/AE HEAD
• T-GUIDE POST
• CAPSTAN SHAFT
• PINCH ROLLER
Note: After cleaning with alcohol, allow the parts to dry thor-
oughly before using a cassette tape.
B. Cleaning the Drive System
The following parts should be cleaned after every 500 hours
of use.
• REEL TABLE
• T MAIN BRAKE
• S MAIN BRAKE
• T MAIN BRAKE
• CAPSTAN FLYWHEEL/PULLEY
• REEL PULLEY
C. Lubrication points
The following parts should be cleaned and lubricated after
every 500 hours of use. Apply one (1) or two (2) drops of oil.
Refer to the "Replacement Parts List" for the stock number of
the recommended oil.
• S REEL TABLE POST
• T REEL TABLE POST
• IDLER PULLEY
CLEANING AND LUBRICATION

FIXTURE ITEM DESCRIPTION P/N
Extension Cable 1 Use for K mecha Drum Motor Connecting Cable 97PB400100
Extension Cable 2 Use for K mecha Capstan Motor connecting Cable 97PB400200
Extension Cable 3 Use for K mecha A/C head and L/C Motor Connecting Cable 97PB400300
Path Adj Fixture Use for X-position adjust/Tape path alignment 97PB396000
Special Driver Use for X-position adjust/Tape path alignment
THE SERVICE FIXTURE
Cable 1 Cable 2 Cable 3 Path Adj Fixture Special Driver
2
AC Millivolt Meter
Sensitivity: 1.0mVAC–400VAC
Dual-Trace Triggered Oscilloscope–with Lo–Cap (X10)
and Direct Probes.
Response: DC–20MHz
Sensitivity: 5mV/div.
Max. Sweep Rate: 0.1µsec./div.
Frequency Counter–7 digits
Sensitivity: 25mV-5V
Range: 50Hz–100MHz
DVM
Range: 0.1VDC–1000VD
Accuracy: 0.5%
NTSC Video Signal Generator–Must provide 1V p-p negative
sync video across a 75 ohm load and produce standard NTSC
75% saturated color bars with a 100% white window.
DC Power Supply
Range: 0-50V, 2A well filtered.
Temperature Controlled Soldering Station–Grounded tip
(Tip temperature: 500°F-600°F).
Note: 500 °F Maximum for leadless components.
AC Variac–Continuously variable.
TEST EQUIPMENT REQUIREMENTS

3
EXTENSION CABLE CONNECTION
A/C HEAD
PCB
TO CAPSTAN
MOTOR
(CABLE2)
TO DRUM
MOTOR
(CABLE1)
(CABLE3)
P201 P502
P601
P501
MAIN PCB
L/C MOTOR
PCB

4
NOTE: PLACING THE UNIT IN THE SERVICE MODE
Service option
For this chassis, the sensors (start/end/reel) are located on the MAIN circuit board, not in the DECK assembly. There is an important
service option that has to be followed to repair the MAIN circuit board with the DECK assembly connected. To imitate the function of
the sensors, insert the SVC Mode Diode (D707) on the MAIN circuit board as shown below.
STOP/EJECT CH DN
POWER
CH UP
D707
REC REW
FWD
PLAY/PAUSE
MAIN P.C.B (TOP SIDE)
PATH FIXTURE CONNECTION/TEST POINT IDENTIFICATION
Refer to the adjustment of the tape transporting system.
Connect to PT01,
!pin-^pin of the
MAIN CIRCUIT BOARD.
CTL pulse test point
GND
S/W pulse test point
ENVE pulse test point
!
^

5
1. Preparation for replacement
a. Soldering Iron
Use a pencil-type soldering iron that uses less than 30
watts.
b. Solder
Eutectic solder (Tin 63%, Lead 37%) is recommended.
c. Soldering time
Do not apply heat more than 4 seconds.
d. Preheating
Leadless capacitor must be preheated before installation.
(130°C~150°C, for about two minutes).
2. Removing the leadless component (Resistors, Capacitors)
Grasp the leadless component body with tweezers and alter-
nately apply heat to both electrodes. When the solder on both
electrodes is melted, remove leadless component with a twist-
ing motion.
LEADLESS (CHIP) COMPONENT REMOVAL INSTRUCTION
Note:
a. Leadless component must not be reused after removal.
b. Excessive mechanical stress and rubbing of the compo-
nent electrode must be avoided.
Note:
a. Do not attempt to lift the component off the board until
the component is completely disconnected from the
board by a twisting action.
b. Take care not to break the copper foil on printed board.
• The following procedures are recommended for the replacement of the leadless components used in this unit.
Chip
Tweezers
Soldering lron

6
3. Installing the Leadless (chip) Component
1) Presolder the contact points of the circuit board.
2) Press the part downward with tweezers and solder both
electrodes as shown below.
4. Removing of Flate ICs (Recommendable manner)
1) For removing solder chips from IC's pins, use a solder
remover or a wiry solder absorber.
2) Heat the IC's tips evenly by moving the chip IC replacing
tool around them, and detach the IC's leads with a tool in
the way of using a lever.
3) Do not reuse ICs removed once (Discard them)
Note:
Do not glue the replacement leadless component to the
circuit board.
Soldering lron
Presolder
Chip IC replacing tool
Soldering lron
Solder
Tweezers

7
LEADLESS (CHIP) COMPONENT IDENTIFICATION
1. Check the followings before S.M.D Troubleshooting
• Cracked or Chipped Component Body
• Cracked or Separated Solder Joints
• Peeling end Terminations or Fractured Leads
2. S. M. D (Surface Mounted Devices) Identification
1) Chip Resistor Identification
* Standard Chip Resistor Code
2) Chip Capacitor Identification
There is no identification of chip capacitor
REMARK Leadless (CHIP) Components are identified on
schematic by means of "(C)" adjacent to symbol
numbers.
• Rejection of Solder from Copper Pads or Component
• Foreign Matter on Copper Pads
• Solder Bridges
= 12x103(1000) = 12000Ω
= 12KΩ
= 47x10° (1) = 47Ω
XXX
123
470
MULTIPLIER (0-9)
2nd SIG. DIGIT (0-9)
1st SIG. DIGIT (1-9)
Examples

8
ABBREVIATIONS
A A or AUD : Audio
A.E. : Audio Erase
AC : Alternating current
ACC : Automatic Color Control
AFC : Automatic Frequency Control
AFT : Automatic Fine Tuning
AGC : Automatic Gain Control
ALC : Automatic Level Control
AM : Amplitude Modulation
AMP : Amplifier
ANT : Antenna
APC : Automatic phase control
ASS'Y or AS : Assembly
AUTO : Automatic
AV or A/V : Audio/Video
B B : Base, Burst
BAL : Balance
BGP : Burst Gate Pulse
BPF : Bandpass Filter
BW or B/W : Black and White
C C : Capacitor, Chroma, Collector
C Rotary : Color Rotary
C-Sync : Composite Synchronization
CAP : Capstan
CAR : Carrier
CATV : Cable Television
CCD : Charge Coupled Devices
CFG : Capstan Frequency Generator
CH : Channel
CHAR : Character
CHROMA : Chrominance
CLK : Clock
CNR : Color Noise Reduction
COMB : Comb Filter
COMP : Comparator, Composite, Compensation
CONV : Converter
CST : Cassette
CTL : Control
CUR : Current
CV : Composite Video
D D : Drum, Digital, Diode, Drain
DC : Direct Current
DD : DC-DC Convert
DEEM or DEEMPH : Deemphasis
DEMOD : Demodulator
DET : Dectector
DEV : Deviation
DFG : Drum Frequency Generator
DOC : Dropout Compensator
DS : Drain and Source
dB : Decibel
E ENVE : Envelope
G GEN : Generator
GND : Ground
H H : High, Horizontal
HA or HEAD AMP : Head Amplifier (PreAmp)
HD : Horizontal Drive, Head
HOR : Horizontal
HZ : Hertz
I I/O : Input/Output
IC : Intergrated Circuit
IF : Intermediate Frequency
INS : Insertion
IR : Infrar Red
K KIL : Killer
L L : Low, Left, Coil
LIM : Limit
LM : Loading Motor
LP : Long Play
LPF : Low Pass Filter
M MAX : Maximum
MIN : Minimum
MIX : Mixer, Mixing
MMV : Monostable Multivibrator
MOD : Modulation, Modulator
M/T or MTR : Motor
N NC : None Connection
NC or NOICAN : Noise Canceller
NL : None linear
NR : Noise Reduction
O OSC : Oscillator, Oscillation
OSD : On Screen Display
OSP : On Screen Program
OTR : One Touch Record
P P-P : Peak-to-Peak
PB : Playback
PC : Photo Coupler
PCB : Printed Circuit Board
PG : Phase Generator

9
PIC : Picture
PIF : Picture Intermediate Frequency
PLL : Phase Locked Loop
PS : Phase Shift
PWM : Pulse Width Modulator
PWR : Power
Q Q : Transistor
QV : Quasi Vertical
R R : Resistor, Right
REC : Recording
REF : Reference
REG : Regulated, Regulator
REMOCON : Remote Control (Unit)
REV : Reverse
REW : Rewind
RF : Radio Frequency
ROT : Rotary
S SEP : Separation
SHARP : Sharpness
SI or S IN : Serial Input
SO or S OUT : Serial Output
SP : Standard Play
STB : Strobe
SVC : Service
SW or S/W : Switch or Switching Pulse
SYNC : Synchronization
SYSCON : System Control
T TJ : Test Jump
TP : Test Pin
TR : Transistor
TRANS : Transformer
TRK : Tracking
TU : Tuner
U UHF : Ultra High Frequency
V V : Volt, Vertical
V-SYNC : Vertical Synchronization
VCA : Voltage Controlled Adjustor
VCO : Voltage Controlled Oscillator
VCR : Video Cassette Recorder
VD : Vertical Drive
VERT : Vertical
VFD : Vacuum Fluorescent Display
VGC : Voltage Gain Control
VHF : Very High Frequency
VR : Variable Resistor or Volume
W W : Watt
W/D : White and Dark
WF : Wave Form
WHT : White
X X-TAL : Crystal
Y Y FM : Luminance FM Signal
Y Y/C : Luminance/Chrominance

10
OPERATION CONTROLS AND FUNCTION
FRONT VIEW
NOTE:
Model-K884N-SJ, K884N-JJ, K884N-SG, K784N-SJ, K784N-JJ, K784N-SG, K884NY-SJ/M, K-884NZ-SJ/M, K884NZ-SG/M
NOTE: Model-K804N-SJ
REC REW PLAY FF
POWER STOP/EJECT
CH
=
=
!@ # $ %
)(
^&*
R
VIDEO INDEX SEARCH SYSTEM
VISS
!
)(
&*^%
@#$

11
!POWER Button
Press this button to turn the VCR on or off. When the VCR is
turned off, the timer recording is automatically turned on if it
has been programmed. When the VCR is turned on, the timer
is automatically turned off. The VCR will stop and be turned
off, if you press the POWER button during record, playback
or fast forward operation.
@STOP/EJECT Button
Stops the normal functions such as record, playback, rewind,
fast-forward, or pause.
Press when the VCR is stopped to eject the cassette.
Press and hold STOP on the remote or STOP/EJECT on the
VCR for approximately 3 seconds to cancel the Express
Recording or the Timer Recording.
#, $ CHANNEL Up or Down Button
Selects next higher or lower channel in the VCR's channel
memory.
%RECORD Button
Press the record button to start recording. REC is indicated in
the multifunction display.
Press this button (at least twice) to select the desired record-
ing time 0:30 (30 minutes) to 4:00 (4 hours).
^REWIND (Reverse Picture Search) Button
Press this button at stop position to rewind the tape after
either recording or playback is completed.
Press rewind button at playback mode to reverse the scan-
ning on the programmed program material visibly.
When the picture reaches to the point where you are looking
for press the PLAY button to resume normal playback.
&PLAY/PAUSE Button
Press this button to play the recorded material.
Playback indicator appears in the multifunction display.
This button is inactive when the VCR is in recording mode.
Pauses the tape for stop-action viewing during playback by
toggle this button.
*FWD (Fast Forward) Button
Press this button at stop position to wind the tape to forward
direction. Press this button at playback mode for an access to
a wanted program material visibly. When the picture reached
to the point where you are looking for, press the PLAY but-
ton to resume normal playback.
(Remote Sensor
Receives signals from the remote control.
Aim the remote at this sensor with no objects between them.
)Multifunction Display
This display is used as an indicator for Function indicator
(PLAY, REC, F.FWD, REW, PAUSE), timer program indi-
cator tape speed (SP, EP), present time of day, VCR/TV,
Line mode (AUX), channel number, tape counter, clock.
In case of LED Display
This display is used as an indicator for function indicator.
(POWER, RECORD, Hi-Fi, VCR, TIMER) by using light
emitting diode.

12
REAR VIEW
NOTE: Hi-Fi model.
ANT IN
RF OUT
CH.
VIDEO
AUDIO
INOUT
L
R34
&
%$ ! #
^@
!CH3 or CH4 Switch
Switch to CH3 or CH4 whichever is not used in your area to
view tape in play mode and to use your TV set as a monitor.
@ANT. (Antenna) IN Connector
Receives a signal from an antennna or cable system when
attached.
#RF OUT Connector
Passes signal to TV the cable supplied.
$Audio Input Connector
Receives audio signal for recording sound from a view cam-
era, external sound equipment, or another VCR.
%Audio Output Connector
Permits audio connection of you VCR to a sound Equipment
another VCR, or monitor.
^Video Input Connector
Receives video signal from a video camera, another VCR, or
other video equipment.
&Video Output Connector
Permits video connection of your VCR to a monitor or
another VCR.

13
Top Cover Removal(Fig. 1)
1. Remove three(3) screws Holding the top cover.
2. Carefully lift the back of top cover and slide it to the rear to
remove it.
Front Panel Removal(Fig. 2)
1. Continued from (Fig. 1).
2. Remove two(2) screws securing front panel & F/L bracket.
3. Release seven(7) tabs holding the front panel.
(Release bottom tabs first)
4. Remove the F/L bracket.
5. Remove the front panel.
Bottom Cover Removal(Fig. 3)
1. Remove the top cover and the front panel.
2. Remove two(2) screws.
3. Lift out the bottom cover in the direction of the arrow.
F/L Door Removal(Fig. 4)
1. Open the F/L door 90 degrees.
2. Remove the F/L door in the direction of the arrow.
IN
OUT
CH
Remove three screws.
Remove two screws
Fig. 1 - Top Cover Removal
Fig. 3 - Bottom Cover Removal
Fig. 2 - Front Panel Removal Fig. 4 - F/L Door Removal
INSTRUMENT DISASSEMBLY
Perform all disassembly procedures in the order presented. When reassembling, use the reverse procedure. Make sure that all
leads/wiring are routed correctly when reassembling.

14
PCB Preamp Assembly Removal(Fig. 5)
1. Remove the top cover, the front panel and the bottom cover.
2. Disconnect the FPC (A).
3. Remove two(2) screws (B).
4. Remove the PCB Preamp assembly in the direction of the
arrow.
Deck Assembly Removal(Fig. 6)
1. Remove the top cover, the front panel, the bottom cover and
the preamp assembly.
2. Disconnect three(3) connectors (A) (B) (C).
3. Remove three(3) screws (D).
4. Pull out the Deck Assembly in the direction of the arrow.
Main PCB Assembly Removal(Fig. 7)
1. Remove the top cover, the front panel, the bottom cover, the
preamp assembly and the deck assembly.
2. Release two(2) tabs (A) and lift out the Main PCB in the
direction of the arrow.
PCB PREAMP ASSEMBLY
REMOVE
ONE SCREW(B)
REMOVE
ONE SCREW(B)
DISCONNECT
THE FPC(A)
RELEASE
ONE TAB(A)
RELEASE
ONE TAB(A)
MAIN PCB
Fig. 5 - PCB Preamp Assembly Removal
DISCONNECT
CONNECTOR (B)
DISCONNECT
CONNECTOR (C) DISCONNECT
CONNECTOR (A)
REMOVE THREE
SCREWS (D)
Fig. 6 - DECK Assembly Removal
Fig. 7 - Main PCB Removal
INSTRUMENT DISASSEMBLY (Continued)

15
1. Earth Bracket Ass’y
2. FE Head
3. S-Slant Pole Ass’y
4. Tension Lever Ass’y
5. Reel Table
6. Main Base Ass’y
7. S-Sub Brake Ass'y
8. S-Main Brake Ass'y
9. Idler Plate Total Ass’y
10. T-Main Brake Ass’y
11. T-Sub Brake Ass’y
12. Relay Lever
13. Capstan Motor
14. Pinch Lever Total Ass’y
15. L/C Bracket Total Ass'y
16. Cam Gear
17. AC Head Total Ass’y
18. T-Slant Pole Ass'y
19. Drum Total Ass’y
20. Head Cleaner Lever As
(K884NZ-SJ/M, K884NZ-SG/M only)
@
#
$
%
^
&*()1
2
3
4
5
6
7
8
9
!
0
Fig. 9 - Tape Transport Mechanism Identification (Top View)
MECHANICAL DISASSEMBLY

16
20. Capstan Motor
21. F/L Rack
22. Connect Plate
23. Reel Belt
24. Reel Gear Total Ass'y
25. Record Safety Lever
26. Loading Lever L
27. Loading Lever R
28. Drum Total Ass'y
29. Loading Rack
0
“
‘
+=
Q
q
W
w
E
Fig. 10 - Tape Transport Mechanism Identification (Bottom View)
MECHANICAL DISASSEMBLY (Continued)

17
1. Top Plate Ass'y
2. F/L Bracket R
3. Prism Link R
4. Release Lever
5. Loading Lever R
6. CST Holder Ass'y
7. Loading Shaft
8. Loading Lever L
9. Door Opener
10. Safety Lever
11. Safety Lever R
!
1
@
#
$
%
^
&
*
(
)
Fig. 11 - Front Loading Mechanism Identification (Top View)
MECHANICAL DISASSEMBLY (Continued)

18
Front Loading Mechanism Removal(Fig. 12)
NOTE:
The front loading mechanism must be in the eject position to
remove it.
1. Remove two (2) screws holding the Front Loading Mecha-
nism.
2. Lift the rear of the cassette loading mechanism
(hole parts for screw) to separate it from the Main Base.
Front Loading Mechanism Disassembly
(Fig. 13~ 17)
1. Remove the front loading mechanism.
2. Remove one (1) screw holding the F/L bracket R and move
the F/L bracket R in the direction of arrow to separate it from
the top plate and the cassette holder assembly.
3. Remove the cassette holder assembly (Fig. 13).
4. Remove one (1) screw holding the prism link R and remove
the prism link R from the F/L bracket R (Fig. 14).
5. Remove one (1) screw holding the prism link L (Fig. 15).
6. Release hook B by pushing it in the direction of the arrow and
remove the door opener (Fig. 15).
7. Press the linked section of the loading lever assembly in the
direction of the arrow and remove the loading lever assembly
(Fig. 16).
8. Remove the safety spring between the safety lever and the
cassette holder (Fig. 16).
9. Remove the release spring between the relelase lever and the
safety lever R (Fig. 16).
MECHANICAL DISASSEMBLY (Continued)
Fig. 12- Front Loading Mechanism Removal
Fig. 14 - F/L Brkt Disassembly
Fig. 15- Top Plate Disassembly
Fig. 13 - Front loading mechanism disassembly

19
NOTE:
Reassemble the cassette loading mechanism using the reverse
procedures. Confirm that the two (2) bosses on the left side of
the cassette holder are inserted into the groove in the left side of
the top plate. Insert the two (2) bosses on the right side into the
F/L bracket R (Fig. 17).
Replacement of the Drum Assembly/Earth
Bracket(Fig. 18)
1. Remove three (3) screws (3).
2. Remove the earth bracket (5).
3. Carefully lift the drum assembly (4) from the deck mecha-
nism taking care not to damage or touch the video heads.
NOTE:
After reassembling the assembly, confirm that the tape runs
smoothly and confirm all tape path adjustment procedures in the
"Mechanical Adjustment" section of this service publication.
Reel belt, Loading Rack, Loading Gers, and
S/T Slant Pole Removal(Fig. 19, 20)
1. Turn the Deck Mechanism updide down and remove the reel
belt.
2. Remove one (1) poly washer !and remove the loading rack
(2) by rotating it CCW.
3. Remove loading gear R #(black) and loading gear L $
(white).
4. Remove the S and T slant poles %and ^by pulling them in
the direction of the arrow.
NOTE:
• Take care not to get grease on the guide rollers.
• When reinstalling, realign the gears as shown in Fig. 20.
MECHANICAL DISASSEMBLY (Continued)
Fig. 16- Loading Lever Ass’y Disassembly
Fig. 17 - F/L Brkt R
#
%
$
Fig. 18 - Replacement of the Drum Total Ass'y and Earth
Brkt Ass'y
!
@
#$
%
^
Fig. 19 - Reel belt, Loading Rack, Loading Gears, S/T slant
pole Removal
ƒRScrews are different