Daewoo DV6T712D User manual

S/M No. : VTB712DET0
Service Manual
MODEL: DV6T712D / DV6T112D
DV6T712P / DV6T112P
DV6T712S / DV6T112S
DV6T722D
DV6T722P
DV6T722S
DAEWOO ELECTRONICS CO., LTD.
Nov. 2002
http : //svc.dwe.co.kr
VCR
DVD
REPEAT
OPEN/CLOSE
DISPLAY
TITLE/PBC
MENU
PR
PR
OUTPUT
PREV
REC
PROGRAM
CLK/CNT
SPEED/ANGLE
TRACKING
TV/VCR
MARK
SEARCH
SYSTEM
PLAY/PAUSE NEXT
ZOOM AUDIO SUBTITLE
RETURN/OK
CLEAR/3D
SETUP
ENTER
✔ 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).

1
SPECIFICATIONS...........................................................................................................2
ADVANTAGES OF THIS PRODUCT ...............................................................................3
TROUBLE SHOOTING................................................................................................................5
WAVEFORMS............................................................................................................................25
CIRCUIT DIAGRAM..................................................................................................................28
PCB CIRCUIT BOARD..............................................................................................................34
INSTRUMENT DISASSEMBLY...............................................................................................37
ELECTRICAL PARTSLIST.........................................................................................................45
CONTENTS

2
SPECIFICATIONS
DVD Audio output standards
Power 230V~, 50Hz
Consumed electricity Hi-Fi : 24W, Mono : 23W
Weight 5.7kg
Dimension (W x H x D) 430mmx91mmx355.5mm
Operative temperature +5°C~40°C
Installation condition Horizontal / Relative humidity under 80%
Signal type PAL/SECAM/MESECAM COLOR
Antenna Input/output U/V-mixed: 75Ωunbalanced
VIDEO input 1.0Vp-p (unbalanced, RCA JACK)
AUDIO input -8.8dBm, RCA JACK
VIDEO output (common use of DVD and VCR) VIDEO output terminal, 1.0 Vp-p unbalanced, RCA JACK, SCART JACK
VIDEO output (DVD only) RGB output (75ΩIn load R: 0.7Vp-p, G:0.7Vp-p, B:0.7Vp-p)
AUDIO output (common use of DVD and VCR) Audio output terminal (2 kinds): -8.8dBm(VCR), 2Vrms(DVD), RCA JACK
AUDIO output (DVD only) Analogue AUDIO output : 2.0Vrms
Digital audio output (OPTICAL, COAXIAL)
Playable tape Very high dense tapes with VHS marks
Playable disc
DVD, VIDEO-CD, CD (12mm), CD (8mm), MP3, CD-R, CD-RW
Tape speed SP: 23.39mm/s, LP: 11.70mm/s
Playtime SP: 3hrs, LP: 6hrs (use of E180tape)
Clock display 24 hrs
Time Recording 8 programs a year
Persistence in power failure 1min
VIDEO S/N (VCR) Over 43dB(Standard recording)
Resolution VCR Over 240 lines (Standard recording)
DVD Over 500 lines (Playback DVD)
AUDIO (VCR) Over 65dB(Hi-Fi), Over 40dB(Mono)
AUDIO (DVD) 90dB
AUDIO dynamic range 90dB
Disc type
DVD VIDEO-CD CD
Analogue Audio output 48/96KHz sampling 44.1KHz sampling 44.1KHz sampling
Digital Audio output 48KHz sampling 44.1KHz sampling 44.1KHz sampling
Optical digital audio output 48KHz sampling 44.1KHz sampling 44.1KHz sampling
Output

ADVANTAGES OF THIS PRODUCT
3
• DVD, VCD, CD, CD-R(MP3), CD-RW, VHS
• DVD one-touch record function
• Watching DVD for recording broadcast
• Integrated remote control (VCR, DVD)
• VISS function
• Multiplex sound playback/record (Hi-Fi Model)
• High Sound Quality of 6 head Hi-Fi (Hi-Fi Model)
• Simple record function
• MP3 file playback function (CD-R disc having records of MP3 files)
• GUI (Graphical User Interface) through OSD (On Screen Display)
By using the [DISPLAY] button on the remote control, information on the DVD/VCD/CD player and disc, can
be displayed on the TV screen.
• Screensaver function (DVD)
• 3D sound (3D sound effect using 2 speakers)
• High bit / High sampling with 27MHz / 10bit video encoder
• High bit / High sampling with 96MHz / 24bit Audio D/A Converter
• Coaxial, Optical digital Audio output (PCM, Dolby Digital, dts)
You can enjoy high-level digital audio by connecting with amp embedded with Dolby Digital / dts decoder.
• Built-in Dolby Digital decoder (DVD)
• Analog audio 2-channels output for DOWNMIX (x1)
• Composite video output (x1)

4
ADVANTAGES OF THIS PRODUCT
• Slow Forward / Reverse playback (DVD)
• Fast Forward / Reverse playback
• Search of title, chapter, and time in DVD disc, and search of time and track time in VCD
and CD
• Various TV aspect (DVD)
4:3 for Pan and Scan, 4:3 for Letter Box, and 16:9 for Wide
• Repeat playback (title, chapter and part for DVD / track, disc and part for VCD/CD)
• Selective Play (DVD/VCD/CD)
You can select and play the desired title / chapter of DVD and track of Video CD/CD in STOP mode.
• 7 languages OSD (On Screen Display) function (DVD)
You can select and display OSD in 7 languages. (E/F/S/G/I/D/P)
• Parental Lock function (DVD)
This function can prevent playback of software that may be unsuitable for children.
• Multi Audio function (DVD)
The audio soundtrack can be heard in up to 12 languages. In the case of SVCD or VCD, it depends on the disc.
(The number of audio languages depends on the software.)
• Multi Subtitle function (DVD)
The subtitle can be seem in up to 12 languages. In the case of SVCD or VCD, it depends on the disc. (The
number of audio languages depends on the software.)
• Multi Angle function (DVD)
This function allows you to choose the viewing angle of scenes which were shot from a number of different
angles. (The number of angles depends on the software.)
• Screen zoom function (DVD/VCD)

5
TROUBLESHOOTING
1. POWER CIRCUIT
✓ CAUTION
You must use insulated trance during the first part test of POWER circuit.
Check IC601,IC701.
No power
POWER cord is ok?
Is 400~200V voltage
obtained at C805 +?
Output voltage of 2nd
parts is normal?
Check
rectifier diode of 2nd parts ;
D821, D822, D823, D825,
D826, D827
Switching
pulse of IC801 pin#4 or
pin#5 is normal?
OK
Exchange POWER CORD
Check
F801,L801,L802,D801.
Exchange rectifier diode of
2nd parts ; D821, D822, D823,
D825, D826, D827.
Check IC801.
NO
YES
YES
YES
YES
YES
NO
NO
NO
NO

2. SYSTEM CIRCUIT
6
TROUBLESHOOTING
No LED display.
Is 5V obtained at IC701
pin #9, 25?
Oscillation at IC701 pin #1?
Specific GRID/SEG doesn’t
function.
Check R705, L601.
Exchange IC701.
Check IC 701 pin #22~24, 27,
28, 30, 31.
Check IC 701 pin #10~12, 14~21.
NO
YES
YES
NO
NO
GRID output at PORT of
IC701?
YES
SEG output at PORT of IC701?
Exchange IC601.
YES
A. LED DISPLAY
NO

7
TROUBLESHOOTING
No power compensation.
Voltage of power fail (IC601
pin#3) at micom is 0.7V over?
More than 3.2V is maintained
for 1 minutes at IC601 pin#37
during Power Cord Open.
Check R644.
NO
YES
B. No power compensation.
YES
Check RESET circuit.
NO
Exchange IC601.

8
TROUBLESHOOTING
Noise appears on the
playback screen.
Is noise diminished by tracking
adjustment.
Noise band is trembled up and
down?
Re-adjust PATH.
Is the height of CTL HEAD normal?
No dust?
Is there problem in CTL Input
circuit and amplifier.
YES
NO
NO
NO
Is there CTL pulse at IC601
pin#97?
Check IC601.
Noise appears on the screen
even though changing tape.
Re-adjust the height of AC
HEAD. Remove the dust.
Check C651, C652, R651~R653
IC601 pin #91, 92, 98.
NO
Re-adjust PATH.
C-1. Bad playback quality (1)
YES
YES
YES
YES

9
TROUBLESHOOTING
Noise appears on the Full
playback screen.
Are SW pulse and HA SW
normal?
Recheck step C-1 (Bad
playback quallty (1)).
Check HEAD AMP connector and
HEAD.
YES
YES
NO
NO
ENVE Wave at PT01 pin #4?
Check VIDEO circuit.
Are there SW, HA SW pulse at
IC601 pin #16, 18?
Check PCB Pattern.
Check IC601.
C-2. Bad playback quality (2)
No broadcasting signal
received
Is the output at IC601 pin#
71(CLK), 72 (DATA) normal?
Is SIF,Video output at
TMI(RF101) pin#18,20 normal?
Check IC 601.
Check IC301.
Check IC601.
YES
YES
NO
NO
NO
Is Video Signal input at IC601
pin#50?
Is there Video output at IC601
pin#52?
Check TMI (RF101) Block.
NO
Check Video Buffer Q156, Q157.
D. No broadcasting signal received
YES
YES
NO
YES
YES
YES

10
TROUBLESHOOTING
Cassette tape isn’t
inserted.
Is 5V voltage obtained at
Loading parts IC601 pin#82?
Is 13V voltage obtained at
Capstan Motor pin#8?
Check at ON/OFF 12.
Check (D822, Q851).
Connect Capstan and Loading Motor.
Check connector and Capstan Motor.
YES
NO
NO
NO
Is 12V voltage obtained at Each
parts of Loading Motor?
Replace Loading Motor.
Check D851 and POWER circuit.
E. No CASSETTE Loading
YES
YES
F. AUTO STOP in Playback mode
VCR stops automatically
in playback mode.
Check R656,C659 and P603 pin#11
Check S603, S604 REEL Sensor.
Is D.PG/FG pulse at IC601
pin#90 normal ?
Is C. FG pulse at IC601 pin#87
normal ?
Is there REEL Pulse at IC601
pin#79, 80?
Check and replace IC601.
NO
YES
YES
YES
NO
Check C.FG(R660, C660)
and P603 pin#1.
NO

11
TROUBLESHOOTING
G. DRUM Motor stops
H. CAPSTAN doesn’t rotate
CAPSTAN doesn’t rotate.
Is 14V voltage obtained at P603
pin#2?
YES
NO
NO
NO
YES
YES
Is Capstan PWM fit to IC 601
pin#77?
Is 3.2V voltage obtained at
P603 pin#5?
Is 2~3V voltage obtained at
P603 pin#9?
Check P603 Connector and
Capstan Motor.
Check 14V.
(Q856,Q857,Q852)
Check Capstan FG
(IC 601 #87).
Check R665, R664, R663,
R666, C665.
Check R661, R667, C664.
DRUM Motor stops.
Is 13V voltage obtained at
P603 pin#8?
YES
NO
NO
NO
YES
YES
Is DRUM PWM fit to IC 601
pin#76?
Is 1.2V voltage obtained at
P603 pin#12?
Check Capstan Motor and
DRUM Motor.
Check ON/OFF 13V
(D851, Q856).
Check DRUM PG/FG
(IC 601 #90).
Check R657, R658,C661,C668.
NO

12
TROUBLESHOOTING
3. VIDEO circuit
EE screen doesn’t appear.
Is Video signal input at IC301
pin#48,50,52,54?
Is 5V obtained at IC301 pin#24,
42, 55, 72, 91?
Is signal input at IC302
pin#1,5,12,13,14,15?
Check LINE JACK and IF circuit.
Check DVD circuit.
Check POWER 5V.
Check LINE JACK and IF circuit.
Check DVD circuit.
NO
A. EE screen doesn’t appear
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
YES
NO
Is signal input at IC601 pin#50? Check PCB Pattern.
Is signal output at IC302 pin#3?
Check IC302 pin#16VCC. Check
IC302 pin#9,10,11(control DC)
Is signal output at IC601 pin# 52? Check IC604 pin#3(C sync).
Is signal output at IC301
pin# 62, 63?
Check VCC of IC301 and
pin #68,69.
Check RF Output. Check LINE.
Is signal input at IC301 pin# 56?
YES
Check PCB Pattern.
NO

13
TROUBLESHOOTING
B. Playback picture doesn’t appear
YES
YES
Is Y signal output at IC301
pin#46?
Is Y signal input at IC301
pin#43?
Is Video signal output at IC302
pin#3?
Check and Replace IC301.
Check PCB Pattern.
Playback picture doesn’t
appear.
Is Envelope output at IC301
pin#79?
NO
NO
YES
Is Video signal input at IC601
pin#50?
Is 5V obtained at IC301
pin#91?
Is SW Pulse input at IC301
pin#70?
Is 5V obtained at IC301
pin#24,42,55,64?
Check POWER 5V.
Check IC601 pin#18.
Check and Replace HEAD.
Check POWER 5V.
YES
NO
NO
Does X301(4.43MHz) oscillate? Check Pattern.
NO
NO
NO
YES
NO
NO
YES
YES
YES
YES
Replace X301.
Is Video signal output at IC301
pin#65? Check IC301 pin# 62.68,69,70.
NO
YES
Check PCB pattern
NO
IC302 pin#9,10,11(control
DC), 16(Vcc)
NO
Check
Pattern.
Check IC604 PIN#3(C sync)
YES

14
TROUBLESHOOTING
Is 5V obtained at IC301
pin#91?
YES
NO
NO
NO
YES
YES
Is IC301 pin#80 REC(H)
HIGH?
Is VIDEO SW Pulse input at
IC301 pin#70?
Is REC signal input at IC301
pin#94, 95, 89, 90?
EP MODE: 89, 90 Pin
SP MODE: 94,95Pin
Check HEAD and Connector.
Is signal input at IC301 pin#
48, 50, 52, 54?
Check POWER circuit.
Check IC601 pin#22.
Check IC601 pin#18.
No recording.
Check EE MODE.
YES
Is FM signal output at IC301
pin#78?
Replace IC301.
NO
NO
YES
C. No recording

15
TROUBLESHOOTING
NO
Is Video signal input at IC601
pin#50?
Check POWER circuit.
No OSD appears.
Is 5V obtained at IC601 pin#
53, 98, 99?
Is Video signal output at IC601
pin#52? NO Check IC 301.
D. No OSD(On Screen Display) appears
YES
YES
NO
Check IC 601.
Check IC 601.

16
TROUBLESHOOTING
4. AUDIO (Hi-Fi MODEL)
No sound in RF E-E
mode
Is there Audio at IC252
pin#4,11?
IC601 pin#27
A.Mute is L or
H?
A. No sound in E-E mode
A. a.RF E-E
NO Check IC121, RF101 block.
Is 12V obtained at IC252
pin#16?
Is RF Audio signal output at
IC252 pin#3,13? Check POWER circuit.
NO
YES
NO
IC601 pin#31 is H, pin#21
is H?
Is about 8V obtained at
IC252 pin#9?
Is about 8V obtained at
IC252 pin #10?
YES
Check IC601.
Check R646, R647.
NO
NO
C at Q904 is L or H?
YES
Check IC601.
Check Output JACK.
HH
L
YES
Check Q904, Q905,
R937,R938,R939
L
Replace IC252.
YES

17
TROUBLESHOOTING
Is there Audio IC252 pin#2,15?
IC601 pin#27
A.Mute is L or
H?
A. b. AV1 E-E
YES
NO Check Input JACK.
Is 12V obtained at IC252
pin 16?
Is RF Audio signal output at
IC252 pin#3,13? Check POWER circuit.
YES
NO
IC601 pin#31 is H,
pin#21is L?
Is about 8V obtained at
IC252 pin#9?
Is about 3.5V obtained
at IC252 pin #10?
YES
Replace IC252.
Check IC601.
Check R646, R647, R911,
R913.
NO
NO
NO
C at Q904 is L or H?
YES
Check
IC601.
Check Output JACK. Check
Q904,Q905,R9
37,R938,R939
HH
L
L
YES
YES
No sound in AV1 E-E
mode.

18
TROUBLESHOOTING
Is there Audio at IC252
pin#1,12?
IC601 pin#27
A.Mute is L or
H?
NO Check signal flow circuit from
IC251 to IC252.
Is 12V obtained at IC252
pin#16?
Is AV2 Audio signal output at
IC252 pin#3,13? Check POWER circuit.
NO
YES
NO
IC601 pin#31 is L?
pin# 21 is L?
Is about 3.5V obtained at
IC252 pin#9?
Is about 3.5V obtained at IC252
pin#10 ?
Replace IC252.
Check IC601.
Check R646, R647, R911,
R913
NO
NO
C at Q904 is L or H?
YES
Check
IC601.
Check Output JACK.
Check Q904,
Q905,R937,R938,
R939
HH
L
L
YES
YES
YES
A. c. AV2 E-E
No sound in AV2 E-E
mode.
Is 12V obtained at IC251
pin#34?
NO
Is 5V obtained at IC251
pin#40?
Check POWER circuit.
YES
NO
Are CLK and DATA obtained at IC251
pin#42, 43?
Check Input JACK.
(Scart AV2)
Replace IC251.
NO
Is AV2 Audio signal output at
IC251 pin#16, 17?
Is there Audio at IC251
pin#8,9 in AV2 mode?

19
TROUBLESHOOTING
No sound in AV-F E-E
mode
Is there Audio at IC253
pin#2,12 in AV-F mode?
Is AV-F Audio signal output
at IC253 pin#14,15?
Is there AV-F Audio at IC252
pin#5,14?
Is 12V obtained at IC253
pin#16?
YES
IC601 pin#27
A.Mute is L
or H?
Check POWER circuit.
A.d. AV-F E-E
YES
NO
NO
NO Check signal flow circuit
IC251 , IC252.
Is 12V obtained at IC252
pin#16?
Is AV-F Audio signal output at
IC252 pin#3,13?
Check POWER circuit.
NO
YES
NO
IC601 pin#31 is L?
pin21 is H?
Is about 3.5V obtained at
IC252 pin#9?
Is about 8V obtained at
IC252 pin#10?
YES
Replace IC252.
Check IC601.
Check
R923,R924,R925,R926
NO
NO
C at Q904 is L or H?
YES
Check
IC601.
Check Output JACK.
Check Q904,Q905,
R937, R938, R939
HH
L
LYES
YES
IC601 pin#32 is L? Check IC601.
NO
Is 3.5V obtained at IC253
pin#10,11? Check R646, R647
NO
Check Input JACK.
(FRONT AV)
Replace IC253