Daewoo DV-K892NZ-QB/M, DV-K592NZ-QB/M Service Manual

Service Manual

Video Cassette Recorder

All models (K30 -Mecha)
SYSTEM : NTSC

Model : DV-K892NZ-QB/M
DV-K592NZ-QB/M

DAEWOO ELECTRONICS CO., LTD.

http : //svc.dwe.co.kr

S/M No. : VK592NTEF0

1

TABLE OF CONTENTS

SPECIFICATION

....................................................................................................... 2

GENERAL ADJUSTMENTS.............................................................................................. 3

TROUBLESHOOTING GUIDES........................................................................................ 4

POWER CIRCUIT................................................................................................................................. 4

SERVO / SYSCON / LOGIC CIRCUIT..................................................................................................... 5

VIDEO CIRCUIT .................................................................................................................................. 12

AUDIO CIRCUIT (Hi-Fi MODEL) .......................................................................................................... 16

AUDIO CIRCUIT (4 HEAD MODEL) ....................................................................................................... 21

WAVEFORMS.............................................................................................................. 24

CIRCUIT DIAGRAM...................................................................................................... 28

INTERCONNECT WIRING DIAGRAM .................................................................................................... 28

POWER SUPPLY SCHEMATIC DIAGRAM ............................................................................................... 29

SYSCON CIRCUIT DIAGRAM............................................................................................................... 30

VIDEO/AUDIO SCHEMATIC DIAGRAM (4 HEAD)................................................................................... 31

VIDEO/AUDIO SCHEMATIC DIAGRAM (Hi-Fi) ........................................................................................ 32

PIF SCHEMATIC DIAGRAM (4 HEAD) ................................................................................................... 33

HI-FI SCHEMATIC DIAGRAM.............................................................................................................. 34

PIF&MPX SCHEMATIC DIAGRAM (Hi-Fi) ............................................................................................. 35

PCB CIRCUIT BOARD .................................................................................................. 36

INSTRUMENT DISASSEMBLY .......................................................................................... 37

ELECTRICAL PARTS LIST ............................................................................................... 43

2

SPECIFICATION

Note: Specifications are subject to change without notice.

Power Input

90~260 Volts AC 60Hz
DV-K592NZ-QB/M (4 Head)

DV-K892NZ-QB/M (4 Head, Hi-Fi)

Power Consumption

17 Watts (4-head Hi-Fi)

17 Watts (4-head)
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 3.5kg : Net (4.3kg : Gross)
Dimensions 36.0 X 9.1 X27.9 cm

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

4-head: Four video record/playback heads

Rotary helical scan
Luma: FM recording
Chroma: converted subcarrier phase shifted recording

Video Signal EIA standard; NTSC color
Antenna 75 ohm input impedance
Video Signal Level 1Vp-p (140 IRE standard)
Audio Input Impedance More than 47K ohm
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/ EP (SLP) mode
T120: 6 hours/ EP (SLP) mode

Fast Forward/Rewind Time 3 minutes (T-120 tape)
Tuning System Auto Program/Cable Compatible/Frequency Synthesis (FS)

3

PG (Pulse Generator) Shifter Adjustment

Test Points: PT01 PIN 3 Main

Video Out Jack Rear Panel

Adjust: R595 (PG Shifter) Main

The Pulse Generator (PG) Shifter determines the video head switching point during playback.
Misadjustment of the PG Shifter may cause head switching noise in the picture and/or vertical jitter.

1. Load the instrument with an alignment tape and play back the color bar signal or monoscope signal.

2. Connect channel-1 scope probe (1V/div.: 50µsec/div.) to PT01 PIN 3. Trigger the scope on channel-1.

3. Connect channel-2 scope probe (1V/div.) to the Video Out Jack.

4. Set the scope to (-) slope and adjust the PG Shifter control R595 so that the trailing edge of the SW 30Hz
pulse is placed 6.5H ± 1H (horizontal) lines before the start of vertical sync pulse.

PG Shifter Adjustment

Stereo Separation Adjustment (Hi-Fi MODEL ONLY)

Test Points: (+) Terminal of C156 Main
Adjust: R191 Main

1. Connect scope prove to (+) Terminal of C156.

2. Receive RF signal.
RF signal condition

1] AUDIO: 1KHz 100% Mod.
2] RF OUT Level: 73dBµV

3. Adjust the STEREO SEPARATION Adjustment R191 so that Audio signal (1KHz) level comes to be
700mVp-p±50mVp-p.

GENERAL ADJUSTMENTS

SWITCHING

SW30Hz
PULSE

VIDEO
OUTPUT

V. SYNC

6.5H

4

TROUBLESHOOTING GUIDES

1. POWER CIRCUIT

Caution :

When checking the primary circuit, be sure to use an isolation transformer.

Is the AC power cord check OK?

Is voltage applied to the terminal
of C806?

Is output voltage of
secondary correct ?

Check secondary rectifier Diode
D809, D810, D812, D819.

Is sw pulse of base
(T801 ) Correct?

OK

Change AC CORD

Check Ic601.

Check IC803, D805, D806, D807, D808.

YES

YES

NO

YES

NO

NO

YES

NO

NO

Check F801/L801/D801/C806.

YES

NO OUTPUT Voltage

1

Change secondary rectifier Diode
D809, D810, D812, D819.

5

TROUBLESHOOTING GUIDES

2. SERVO / SYSCON / LOGIC CIRCUIT

Is 5V supplied to

pin of IC601?

Is 5V applied to

Check X601.

pin of IC601?

Is 5V applied to pin

of IC601 ?

Is 4V applied to collector

of Q711, Q712, Q713,

and Q714?

Check IC602.

Check D813.

Check IC601.

Check R636, C616.

Check Q711, Q712,

Q713 and Q714.

YES

YES

YES

YES

NO

NO

NO

A.

NO

NO

LED ARRAY does

not operate.

Check the pulse signal

of pin ~ of IC601

and LD701.

YES

37

34

4

20

33

6

TROUBLESHOOTING GUIDES

Is each key pulse

applied to pin

of IC601?

Check key matrix

circuit.

Check IC601

When disconnecting

the power cord,Is 5.0V

at pin of IC601?

Do pin and

of IC601
oscillate?

Check IC601.

Check C820.

Check X601, R603,

C604 and C605.

NO

YES

YES

YES

YES

NO

NO

NO

B.

C.

Check the IC602

RESET circuit.

Is 0V applied to

pin of Ic601?

YES

NO

Check the R636, C616.

LED ARRAY is
lit but key does

not operate.

1 hour back up

timer does not

operate.

Is +5V applied to

34

4

35

37

11

12

36

pin of IC601?

7

TROUBLESHOOTING GUIDES

Is the output of pinIs the output of pinIs the output of pinIs the output of pin

YES

D.

Check the Video,

Audio output signal of

pin , of

TMI BLOCK (RF101)

Check the TMI

BLOCK.

Check IC601

Check the

Video IC.

Check the video signal

pin of IC601

Is the output of pin

normal?

YES

NO

Check the video output

signal pin of IC301

YES

YES

NO

NO

YES

E.

Is 5V supplied

to pin of Ic601?

NO

YES

Is 5V applied

to pin of Ic601?

YES

Check X601

Is 4V applied to the collector

Is 5V applied to

of Q711,Q712,Q713,Q714?

pin of Ic601?

Check D813.

YES

YES

Check pin ~ of

IC601 and LD701.

YES

NO

Check IC602

NO

Check IC601

NO

NO

Check L806

Check R636, C616

When change the

channel broadcast

signal is not received.

LED ARRAY

does not operate.

Check the

IC601.

NO

YES

Check the Video

output Buffer Q101

29

71

17

20

72

52

37

34

4

and of IC601

29 33

8

TROUBLESHOOTING GUIDES

Noise appears
although adjusting
tracking.

YES

Adjust tracking.

Noise shakes up
and down on the
screen.

YES

Is CTL pulse applied
to pin of IC601?

YES

NO

NO

Check IC601

NO

Noise appears
although change
cassette tape.

CTL HEAD height is
normal and there is
not dust.

YES

Check CTL input in circuit (R501, R502, R503, C501),
CTL AMP VREF (IC601 pin , )
and AMP Vcc (IC601 pin ).

YES

Check and
re-adjust the
Path of Deck.

NO

Adjust the HEAD
height and remove
dust.

F.

Playback picture
is not good.

97

98

91 92

9

TROUBLESHOOTING GUIDES

Noise appears
over the entire
screen

YES

Check TS Flowchart F

NO

Are SW pulse and
HA SW applied to
VIDEO circuit?

YES

NO

Is SW pulse supplied
from pin , of Ic601?

NO

Check D.PG input
(IC601 pin )
and connector (P502)

YES

Check PCB pattern

Is Enve.waveform
supplied to at
pin of PT01?

YES

NO

Check VIDEO circuit.

Check connector. Head
Amp and Clean heads.

Is Reel pulse
applied to pin and
of IC601?

YES

NO

YES

NO

Check REEL
sensor part.

Is D.FG applied to
pin of Ic601?

Check connector (P502) and

D.FG circuit (R504, C509)

G.

H.

Is C.FG applied
to pin of Ic601?

NO

Check connector (P501)
and C.FG circuit (R510,
C511)

YES

Check IC601

Playback picture
is not good.

VCR goes
to auto stop during
playback

16 18

90

4

79

80

89

87

10

TROUBLESHOOTING GUIDES

I.

Check power circuit.

NO

Is 12V supplied to P502
pin ?

YES

Check IC601 and D.FG.

NO

Is D.PWM (pin )
of IC601 correct?

Check R508, R509 and C514

NO

Is the voltage of P502 pin

1.2V?

Check connector (P502)
and DRUM Motor

J.

YES

YES

Check power circuit.

NO

Is 12V supplied to P501
pin ?

YES

NO

Is the voltage of pin
P501 3.2V?

YES

Check R513, R514.

NO

Is the voltage of P501
pin 2.5V?

YES

Check IC601 and C.FG.

NO

Is C.PWM (pin )
of IC601 correct?

YES

NO

Is the voltage of pin P501
2~3V?

YES

Check connector (P501)
and capstan motor

Check R511, R512,
C512.

Check circuit of R515,
R516, R517, C513

Drum Motor does not rotate.

Capstan Motor does not rotate.

3

76

2

7

6

4

77

5

11

TROUBLESHOOTING GUIDES

K.

NO

Is CAM SW DATA
(IC601 pin , , , )
Correct?

YES

YES

Check Loading Motor.

Check IC601

LED ARRAY shows "Err".

82 84 86

66

Is 12V applied to pin of
IC604 ?

Check power circuit.

YES

NO

L.

Check motor drive circuit

Check IC601.

Is 5V applied to pin of
IC601 when CST IN?

YES

NO

Is 5V applied to pin of
PJ601 when CST IN?

YES

NO

Check connector
(PJ601 pin and ) and loading
motor in DECK Mechanism.

Cassette loading inoperative.

81

7

1

1

2

12

TROUBLESHOOTING GUIDES

3. VIDEO CIRCUIT

Is video signal input into pin
, , of Ic301?

YES

NO

A.

Is 5V supplied at pin ,
of Ic301?

YES

NO

Is signal output from pin
of Ic301?

YES

NO

Check IIC CLK, DATA

Is 5V suppiled to pin ,
and of Ic601?

Check PCB pattern

Is signal input into pin of
Ic601?

YES

NO

Is signal output from pin of
Ic601?

YES

NO

YES

Check power circuit.

RF out

YES

Line out

Check power
circuit

NO

Check PIF circuit and
LINE IN JACK

EE MODE Picture NG

Check IC601

YES

34 36

38

16

58

29

50

52

53 98

99

13

TROUBLESHOOTING GUIDES

101010

Is envelope output from

pin of IC301 ?

YES

NO

B.

Is signal output from

pin of IC301 ?

YES

YES

Is signal input into

pin of IC301 ?

YES

NO

NO

YES

Is signal output

pin from IC301 ?

YES

YES

Is signal input into
pin of IC301 ?

Is separated Y signal

Is separated Y signal Is separated Y signal

output from pin of IC301?

input into pin of IC301? output from pin of IC301?

YES

YES

Is separated C signal

Is separated C signal Is separated C signal

output from pin , of IC301?

input into pin of IC301? output from pin of IC301?

YES

Is composite video signal

output from pin of IC301?

YES

Check OSD circuit

NO

NO

YES

NO

YES

NO

NO

NO

NO

NO

NO

NO

NO

NO

YES

YES

Is 5V supplied at
pin of IC301 ?

Is 5V supplied to

pin , of IC301?

Check IIC DATA, CLK

Check power circuit

Is SW pulse input into

pin of IC301?

Check pin of IC601

Check Power circuit

Check Q302

Check Q301

Change IC301

Change IC301

Is CLOCK (3.58MHz)
supplied at
pin of IC301 ?

Does X301 crystal
(3.58MHz) oscillate?

Change X301

Clean head or
change head

PB video signal missing.

74

18

17

21

20

43

41 46

57

61 51

59

29

16

58

11

18

49

87

14

TROUBLESHOOTING GUIDES

YES

C.

YES

NO

YES

YES

YES

YES

NO

NO

NO

NO

Is Iuminance and color
signal output from
IC301 pin , ?

Is +5V supplied at
IC401 pin ?

Is REC(H) signal
supplied IC301 pin ?

Is SW pulse input
into IC301 pin ?

Is REC signal output from
IC301 pin , ?
SP mode : pin
EP mode : pin

Check video head and connector

Check EE mode

Is signal input into
IC301 pin , , ?

Change IC301

Check IC601 pin

Check REC(H)

Check power circuit

Record video signal NG

12

71

87

30

11

84

90

90
84

8

34

36

38

15

TROUBLESHOOTING GUIDES

YES

D.

Does X602 crystal (14.318MHz)
oscillate?

YES

NO

Is 5V supplied at IC601 pin , , ?

YES

NO

Check power circuit.

OSD Character Incorrect.

Check X602

Change IC601

53

98

99