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SM NO : DPC7409001
SERVICE MANUAL DPC-7409
(Product Code: )
Portable DVD Player
SPECIFICATIONS
Power source : 9V/2A
Power consumption : 10W
Dimension : 210(W) x 162(H) x 38(D)mm
Net Weight : Approx. 0.9kg.
Specifications subject to change without notice
REFERENCE No.
No.:
Revision: 0.1
Date:
Service Manual for
Portable DVD DPC-7409 Series
Name of Company DAEWOO ELECTRONICS CORP.
Approved
b
SIGNATURE DATE APPROVED BY DATE
/
REVIEWED BY
/
PREPARED BY
/
Please return 1 copy for our confirmation with
your signature and comments.
Revision Record
Date Rev No. Section Description
05/Aug/2007 0.1 New edition
Design and specifications are subject to change without notice.
All trademarks used in the specifications are the property of their respective
1. General Descriptions 1
1.1 Model Features 1
1.2 Information 2
2. Electrical Characteristics 3
2.1 Optical Characteristics 3
2.2 Electrical Characteristics 3
2.3 System Block Diagram 4
2.4 Schematic Circuit Diagram 5
3. Power 10
3.1 Power Supply 10
3.2 Rechargeable Battery 10
4. Dimension & Physical Characteristics 12
4.1 Outline Dimension 12
4.2 Physical Characteristics 12
4.3 Exploded View 13
5. Regulatory Standards 14
5.1 Safety 14
5.2 EMI 14
5.3 Ergonomics 14
6. Service Tools and Equipment 15
6.1 Service Tools and Equipment 15
6.2 Storing and Handling Test Discs 15
6.3 Notes 16
7. Spare Parts 17
7.1 Mechanical parts list 17
7.2Electrical parts list 17
8. Trouble shooting 18
8.1 Error Code Table 18
8.2 Debug & Trouble Shooting 19
1 General Descriptions
1.1 Model Features
Video: DVD Playback, MPEG4(option) ,DivX(DivX Model),Kodak Picture CD
compatible& JPEG readable
Audio: CD, CD-R, CD-RW, MP3, WMA Playback
Firmware Upgradable
Dolby Digital Output
7" active-matrix TFT screen, 16:9 wide aspect ratio
Composite Video Output
USB/CARD function supported
Ultra dimension & light weight: 210mm(W) x 162mm(H) x 38mm(D) / 900g (around)
Slim size wireless remote control
Rechargeable battery pack
12-volt car cigarette lighter cable
Universal AC/DC power adapter
Audio/video cable for TV connection
Built-in stereo speakers
Stereo headphone jack
Parental Lock
Anti Shock Protection
-1-
1.2 Information
DVD,VCE,CD,MP3,CD-R,CD-RW,MPEG4,JPEG,WMA
Disk Format
Kodak Picture CD, DivX (DivX Model)
Video System NTSC/PAL/Auto
Video Decompression MPEG-4
Video Output 800~1200mVpp/75ohm
Audio Characteristic 2-Channel Analog
Analog Output 1.0~2.0Vrms/10K ohm
DVD:48kHz Sampling:20Hz-20kHz
Frequency Response
CD:20Hz-20kHz
S/N Ratio >=90dB
Dynamic Range >=80dB
Audio-Output
<=-65dB
Noise & Distortion
Headphone Jack Headphone Jack x 1
LCD Display 7"active-matrix TFT type
Audio/Video Section Audio/Video Output x1
Headphone Jack 16ohm(30mW)
Line Voltage AC 100~240 VAC+/-10%(50/60Hz),(Adapter)
Power Consumption About 10W
Remote Control DC 3V Infra-red
Dimensions 210mm(L) x 162mm(W) x 38mm(H)
Weight 900g(around)
Slim Size Remote Controller with 3V Battery
Accessories 12-volt Car Cigarette Lighter Cable Universal
AC/DC Power Adapter Audio/Video Cable
Li-Rechargeable Battery Pack
-2-
2 Electrical Characteristics
2.1 Optical Characteristics
Parameter Specifications Unit
Screen Size 7.0 (16:9 diagonal) inch
Display Format 480x3(RGB) 234 dot
Active Area 154.08 (W) 86.58 (H) mm
Dot Pitch 0.107 (W) 0.370 (H) mm
Pixel Configuration Stripe
Outline Dimension 164.9 (W) 100.0 (H) 5.7 (D)(typ). mm
Surface Treatment Anti-Glare
Weight 164 g
2.2 Electrical Characteristics
DVD/ SVCD/ VCD/ CD system decoding, packeted element streams and audio, video
element streams.
Fully digital servo processing (focusing, tracking, sledge and spindle servo control)
Fully digital calibration (focusing/ tracking offset and balance)
Digital phase lock loop with phase equalizer
Support Audio/ Video/ Photograph decoding and programming
1.8V and 3.3V dual power supply, 256 pin PQFP
-3-
2.3 System Block Diagram
2.3.1. The System Block Diagram & the Block's Function Description
LED BACK-LIGHT
DRIVER
DISPLAY
7" TFT LED
AT070TN07-R(A)
DC To DC
MP1411
Servo +MPEG
MT1389P
Loader
HK-8707
-4-
2.4 Schematic Circuit Diagram
(1)POWER_MPS
-5-
(2) SERVO&MPEG
-6-
(3) SDRAM&FLASH&EEPROM
-7-
(4) VIDEO OUTPUT
-8-
(5) AUDIO OUTPUT
-9-
3 Power
3.1 Power Supply
Input voltage:
Normal voltage: 100 to 240 Vac.
Input frequency:
Normal frequency: 50 to 60 Hz.
Input current: 1A at 100Vac at rated load 2A.
Inrush current: The inrush current will not exceed 30A at 100V AC input cold start 25.
3.2 Rechargeable Battery
Output Voltage 8.4~6.5V
Cut-off Voltage 5.7~6.5V
Charge voltage the battery pack should be charged when the input voltage is from 9V to
12V
Charger a.) Hiteker DC9V/2A adaptor.
b.) Hiteker DC9V/2A adaptor and Portable DVD
LED is in red color when the battery pack is in charging; and turns into green color
when batter pack is full.
If the battery pack is in Full status, no matter use adaptor charge directly or link
DVD to charge again, the LED must be turn into green color in 15 min.
The cycle life of battery pack has more than 300 cycles.
Charge: The battery pack must be able to charge when used the Hiteker DC9V/2A
adaptor or Hiteker DC9V/2A adaptor and portable DVD (power off status).
Discharge: Using the battery pack as the power source for portable DVD that in DVD
disc playing mode, the discharging time must be exceed 3hrs.
3.2.1 Electrical Protection
The battery pack shall be capable of withstanding a continuous short circuit output without
damage.
- 10 -
The battery pack shall return to normal operation only after the fault has been removed.
A thermal fuse must be added on the surface of cell body to protect the battery pack.
A polyswitch must be add to protect the battery pack.
Charge & Play Time of Battery Pack
Charge Time DVD Title Play Time
Styling L
(hr) (hr)
For DPC-7909 Series
Li 2200mAh 6~7 3
- 11 -
4 Dimension & Physical Characteristics
4.1 Outline Dimension
210mm(W) x 162mm(H) x 38mm(D)
4.2 Physical Characteristics
- 12 -
4.3 Exploded View
- 13 -
5 Regulatory Standards
5.1 Safety
UL
FDA
5.2 EMI
CE
FCC
5.3 Ergonomics
Dolby
- 14 -
6 Service Tools and Equipment
6.1Service Tools and Equipment Table
Application Name
DVD Testing Disc
General
General Tools (screwdriver etc.)
CD Testing Disc
Confirm
VCD Testing Disc
Oscillograph
Adjust Probes
AV Cables
TV Monitor
Searing-iron
Grounding for electrostatic
Antistatic wrist strap
breakdown
Conductive material (steel sheet)
6.2 Storing and Handling Test Discs
It is important for a DVD testing disc keeping its surface precise.
Please care for storing and using it.
1. Do not place the disc on worktable directly after using.
2. Do not store discs in places subject to direct sunlight or near heat sources.
3. Do not place the disc on a glass surface. It may damage the disc. If this happened,
please use a new testing disc adjust DVD player precision.
- 15 -
6.3 Notes
PLEASE READ ALL NOTES GIVEN IN THIS MANUAL.
Locate
Place the unit on a firm, flat surface.
Do not place in a high temperature (upwards of 40 ) or high
wet(upwards of 80 percent) area.
Do not place in an area with a lot of dust.
Keep away from direct sunlight &domestic heating equipment.
Do not fall any objects into the unit.
Care should be taken so that liquids are not spilled into the unit openings.
Such situations could result in fire or electrical shock.
Keep the DVD video player away from any magnetic articles such as
speaker etc.
Superposition
Please place the DVD player horizontally. Do not place a heavy
object(amplifier, receiver) on it. The object may fall, causing serious
personal injury or death.
This unit should be situated away from heat source, such as amplifiers,
radiators,stoves or any other units producing heat.
Condensation
Lens could be moistening in these cases.
Turn on heater shortly,
In a very wet room,
Move the player from a cold environment to a heat environment quickly.
Being moisture inside the play could operate normally. Please turn on power
and wait about an hour for drying the moisture.
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7.Spare Parts
7.1 Mechanical parts list
Part NO Part Name Description Remark
GKB2.855.8448A3MX--R Main Board MPEG Board With Divx
LED Back-LightDrive LED Back- For All
GKB2.855.8518MX-R
PCB LightDriver
HK8707-R Loader DVD Player For All
AT070TN07-RA TFT Screen TFT screen For All
GKB4.819.8135-02-R RechargeableBattery Li 2200mAH For All
GKB2.930.8093-05-R AC/DC Adapter DC 9V-2A Max For All
GKB2.018.8143WX-R Remote Control Remote Control For All
7.2 Electrical parts list
Location Part NO Part Name Description Remark
U7 MT1389DE-P-R MPEG IC MTK 1389P With Divx
U12 S29AL016D70-R Flash Memory IC 16M Memory With Divx
EM638165TS-7G-R SDRAM IC 64M SDRAM With Divx
MOTOR DRIVE
U8 W43023-R DRIVE IC With Divx
IC
U13 IC24C04A-R EEPROM IC EEPROM IC With Divx
U2/U4 ICMP1411-R Power Trans IC DC TO DC With Divx
U14/U15/ AUDIO
D4558-R AUDIO Trans IC With Divx
U17 Amplifier
- 17 -
8 Trouble Shooting
8.1 Error Code Table
CODE Descriptions of Error Note
Power Test
T01 No power
T02 Power Led indicator is not on or insufficient brightness
T03 Loading time too long
T04 Remote control bad sensing or not functional
System stays in the Run In condition after power on, can't be
T05
tested
T06 System down at power on
T07 System down during playing
T08 Power on unstable
T09 Abnormal sound in the system
Disc Drive Test
T10 Can't read the disc(No Disc)
T11 Disc drive no action or locked
T12 Disc drive scratches the disc
T13 Some discs can't be played(can't play CD or VCD or DVD)
T14 Head does not work
T15 Spindle does not work
Video Test
T20 No video/abnormal(Please indicate theabnormal condition)
Video:no video/abnormal(Please indicate the abnormal
T21
condition)
VCD picture abnormal(Please indicate the abnormal
T22
condition)
DVD picture abnormal(Please indicate the abnormal
T23
condition)
T24 Picture subtitle display abnormal or no display
Setting menu picture abnormal(Please indicate the
T25
abnormal condition)
Audio Test
Audio/left sound channel(AOL) does not have
T30
waveform (sound) or waveform (sound) abnormal
Audio/right sound channel(AOR) does not have
T31
waveform (sound) or waveform (sound) abnormal
T32 MP3 abnormal sound
Audio no waveform (sound) or waveform (sound)
T33
abnormal
Earphone Test
Earphone Audio no waveform (sound) or waveform
T40
(sound) abnormal
Function Key Test
T50 Video can't be still or stopped
T51 Can't execute fast forward or rewind
T52 Panel button
- 18 -
System Setting Test
T60 Can't enter the system setting
T61 System can't play or system down after setting
TFT Test
T70 TFT image and color error
T71 TFT image is black and white
T72 TFT image shakes and is distorted
T73 TFT PAL color strip
T74 TFT ripple
8.2 Debug & Trouble Shooting
Please check the PCB for any missing components and bad soldering
T01 No Power
Main Board
A. Check for components on the Main Board to see if there are any short circuits.
B. Check for the power adapter to see if the 9V power is abnormal.
C. Check for components CE2,C21,C22,C8,C9 on the Main Board to see if there
are any short circuits.
D. Check for component U2,U4 on the Main Board to see if the switch have function.
E. If none of the above actions is effective, please change Main Board.
T02 Power LED indicator is not on or insufficient brightness
Main Board
A. Open the cover of the portable DVD-player to inspect if LED functions
normally.
B . Replace with a good one or re-plug it to see if the LED lights up when
Power ON.
C . If the above actions are not working, replace the Main Board.
T03 Loading time too long
Main Board
A. Check the flat cable to see if it is adhibited to the right place.
B. Remove the cover to see if the resistors or resistor-array adjacent to U8 and or
U7, to see if there is any cold soldering, hollow soldering, misplaced
- 19 -
soldering,or wrong part.
C. If the above actions are not working, replace the Main Board.
T04 Remote control bad sensing or not functional
Remote control
A. If the main body of the system works normally, then making sure that the
battery of the Remote control has sufficient power, if it is not, replace the
battery.
Main Board
A. Remove the top cover and the panel. Check to see if IR1 has short
circuit, broken circuit, hollow soldering, or other problems. Also check if the
pins 1 of IR1 have power.
B. If the above actions are not working, replace the Main Board.
T05 System stays in the Run In condition after power on, can't be tested
Main Board
A. The same refer to T03.
B. If the above actions are not working, replace the Main Board.
T06 System down at power on
Main Board
A. Remove the top cover, check all flat cables in the system to see if they are
correctly plugged to the fixed positions, or re-plug them.
B. Check the pin 7 of U9 to see if it is high voltage.
C. If the above actions are not working, replace the Main Board.
T07 System down during playing
Main Board
A. Exclude the condition of using battery. (The system will down when the
voltage is too low.)
- 20 -
B. Disassemble U12 F/W, replace with a good one or re-plug it to see if the
symptom will disappear.
C. Remove the top cover, check all flat cables in the system to see if they are
correctly plugged to the fixed positions, or re-plug them.
D. Check the capacitors CE26 and the diode D11 to see if the reset circuit works
normally.
E. If the above actions are not working, replace the Main Board.
DVD ROM
A. Check the loader to see if it is not stable (any condition that some of the
discs can't be played). If so, replace the loader.
DVD DISC
A. Check the Test Disc to see if there is any serious scratch or ring shape,
circular shape scratches, if so, replace the Test Disc and test again.
T08 Power on unstable
Main Board
A. Remove the top cover, check all flat cables in the system to see if they
are correctly plugged to the fixed positions, or re-plug them.
B. Check the U6 to see if it works normally with a 1.8V output
voltage.
C. Check the reset circuit.
D. If the above actions are not working, replace the Main Board.
T09 Abnormal sound in the system (Power on abnormal sound)
DVD ROM
A. Check the loader to see if it is the source of the abnormal sound. If so, replace the
loader.
B. If the abnormal sound comes from the audio speakers, check the audion
NPN 3904 type Q6/7/12/14/15/13 to confirm the mute circuit works normally.
If not ,change the audion.
- 21 -
T10 Can't read the disc (NO DISC)
Main Board
A. Remove the top cover, check the 24-pin flat cable in the system to see if
they are correctly plugged to the fixed positions, or re-plug them.
B. Check the resistors or resistor-array adjacent to U8 and U7 to see if
there is any hollow soldering or cold soldering.
C. If the above actions are not working, replace the Main Board. If it is still
not working, replace the loader.
DVD ROM
A. Check the loader to see if it can't read. If so, replace the loader.
T11 Disc drive no action or locked
Main Board
A. Remove the cover. Check to see if it is caused by mis-assembly.
B. Check the resistors or capacitors adjacent to U8 to see if there is any
hollow soldering or cold soldering.
C. If the above actions are not working, replace the loader. If it is still not working,
replace the main board.
T12 Disc drive scratches the disc
Main Board
A. Check the resistors or capacitors adjacent to IC (U7) to see if there is any
hollow soldering, cold soldering, wrong part, or misplaced soldering.
B. If the above actions are not working, replace the loader. If it is still not working,
replace the main board.
DVD ROM
A. Check the loader to see if it is the cause of disc scratching. If so, replace
the loader.
T13 Some discs can't be played(can't play CD or VCD or DVD)
Main Board
A. Check the resistors or capacitors adjacent to IC(U7) to see if there is any
- 22 -
hollow soldering, cold soldering, wrong part, or misplaced soldering.
B. If the above actions are not working, replace the loader. If it is still not
working,replace the main board.
T14 Head does not work
Main Board
A. Remove the top cover, check the 24-pin flat cable and the 4-pin able in
the system to see if they are correctly plugged to the fixed positions, or re-plug
them.
B. Check the resistors or capacitors adjacent to IC(U7) to see if there is any
hollow soldering, cold soldering, wrong part, or misplaced soldering.
C. If the above actions are not working, replace the loader. If it is still not working,
replace the main board.
T15 Spindle does not work.
Main Board
A. Remove the top cover, check the 4-pin flat cable in the system to see if
they are correctly plugged to the fixed positions, or re-plug them.
B. Check the resistors or capacitors adjacent to IC(U7) to see if there is any
hollow soldering, cold soldering, wrong part, or misplaced soldering.
C. If the above actions are not working, replace the loader. If it is still not
working, replace the main board.
T20 No video / abnormal
Main Board
A. Remove the top cover, check all flat cables in the system to see if they are
correctly plugged to the fixed positions, or re-plug them.
B. Use oscillograph to measure if Y1 generates 27MHz. If it does not generate
said frequency, and the problems such as cold or hollowsoldering have
Beenruled out, it maybe Y1 work abnormally . Replace Y1 with a
27MHz fundamental frequency oscillater.
C. Check if U7 has any problem.
D. Check if switch for TFT on/off is normal; replace a new one if necessary.
- 23 -
E. Check VR1 is using the correct component. Also check if it's damaged.
F. Adjust VR1 to the appropriate value.
G. If the above actions are not working, replace the Main Board.
DVD ROM (less likely to happen)
A. If it is useless to change the main board, then replace the loader.
T21 Videono video / abnormal
Main Board
A. Remove the cover. Check the main board to see if there is any cold or hollow
soldering and rule out the problem.
B. Remove the top cover, check all flat cables in the system to see if they are
correctly plugged to the fixed positions, or re-plug them.
C. Check RLC following CVBS to see if there is any wrong parts, cold and
hollow soldering, short circuit, broken circuit, broken parts and rule out the
problem.
D. If the above actions do not work, then check U7 Pin191/184/185/187 to see if
there is CVBS signals.
E. If the above actions are not working, replace the Main Board.
T22 VCD picture
Main Board
A. Check main board to see if there is any cold or hollow soldering and short-circuit
problem and rule out the problem.
B. Check the resistors or capacitors adjacent to IC(U7) to see if there is any hollow
soldering, cold soldering, wrong part,or misplaced soldering.
C. If the above actions are not working, replace the Main Board.
DVD ROM
A. If the abnormal picture is the problem of pause or skipping tracks, then making
sure if the disc has any scratches or dirt,if no such problems then replace the
loader.
T23 DVD picture
Main Board
- 24 -
A. Check U7 to see if there is any cold or hollow soldering and short circuit problem
and rule out the problem.
B. Check the resistors or capacitors adjacent to IC(U7) to see
if there is any hollow soldering,cold soldering, wrong part, or misplaced
soldering.
C. If the above actions are not working, replace the Main Board.
DVD ROM
A. If the abnormal picture is the problem of pause or skipping tracks, then making
sure if the disc has any scratches or dirt,
if no such problems then replace the loader.
T24 Picture subtitle abnormal or no display
Main Board
A. Remove the top cover and dis-assemble F/W (U7). Replace it with
a good F/W or re-plug it, then check if the action is normal. Otherwise replace
the F/W.
B. Check U7 to see if there is any cold or hollow soldering and short circuit
problem and rule out the problem.
C. If the above actions are not working, replace the Main Board.
T25 Setting menu picture
Main Board
A. Check U7 to see if there is any cold or hollow soldering and rule out the
problem.
B. Remove and dis-assemble U11 with a 64Mbit SDRAM.
C. If the above actions are not working, replace the Main Board.
T30 Audio /left channel (AOL) no sound or abnormal sound
Main Board
A. Remove the cover. Check U7 on the Main board to see if there
is any cold soldering, hollow soldering, or damage. Rule out the problem.
B. Check all parts following AOL to see if there is any cold or hollow soldering,
short circuit, broken circuit, parts missing, wrong parts and rule out the
problem.
- 25 -
C. If the above actions are not working, replace the Main Board.
T31 Audio /right channel (AOR) no sound or abnormal sound
Main Board
A. Remove the cover. Check U7 on the Main board to see if there
is any cold soldering, hollow soldering, or damage. Rule out the problem.
B. Check all parts following AOR to see if there is any cold or hollow soldering,
short circuit, broken circuit, parts missing, wrong parts and rule out the
problem.
C. If the above actions are not working, replace the Main Board.
T32 MP3 abnormal sound
Main Board
A. Remove the top cover, check all flat cables in the system to see if they are
correctly plugged to the fixed positions, or re-plug them.
B. Check the resistors or capacitors adjacent to IC(U7) to see
if there is any hollow soldering or cold soldering.
C. If the above actions are not working, replace the main board.If it is still not
working, replace the loader.
T33 Audio no waveform (sound) or waveform (sound) abnormal
Main Board
A. Remove the cover. Check U7 on the main board to see if there
is any cold or hollow soldering and rule out the problem.
B. Check all parts following AOL and AOR to see if there is any cold or hollow
soldering, short circuit, broken circuit, parts missing, or wrong parts. Rule out
the problem.
C. If the above actions are not working, replace the Main Board.
T40 Earphone Audio no waveform (sound) or waveform (sound) abnormal
Main Board
A. Remove the top cover, check all flat cables in the system to see if they are
correctly plugged to the fixed positions, or re-plug them.
B. Check U7U14U15to see if there is any cold or hollow soldering and
- 26 -
rule out the problem.
C. If the above action does not work after the inspection, replace the main board.
T50 Video can't be still or stopped
Remote control
A. If the main body of the system works normally, then making sure that the battery
of the Remote control has sufficient power,if it is not, replace the battery.
Main Board
A. Check to see if U7 is damaged, and check all parts following U7 to see if
there is any cold or hollow soldering, short circuit, broken circuit, broken
parts, parts missing and rule out the problem.
B. If the above actions are not working, replace the Main Board.
T51 Can't execute fast forward or rewind
Main Board
A. Check to see if U7 is damaged, and check all parts following U7 to see if
there is any cold or hollow soldering, short circuit, broken circuit, broken-
parts, parts missing and rule out the problem.
B. If the above actions do not work after the inspection, it means the main board or
F/W is bad. Replace the main board or re-burn the F/W (U12).
T52 Panel button
Main Board
A. Check U7 to see if there is any cold or hollow soldering and reverse
soldering of IC or parts missing.
B. If the above actions do not work after the inspection, check
the keystrokes to see if there is any damage.
C. If the above actions are not working, Replace the control board or the main board.
T60 Can't enter the system setting
Main Board
A. Check U7 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
B. If the above actions do not work after the inspection, it means the main board or
- 27 -
F/W is bad.
C. If the disk is abnormal, ask for a new version software .
T61 System can't play or system down after setting
Main Board
A. Check U7 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
B. If the above actions do not work after the inspection, it means the main board or
F/W is bad. Replace the main board or re-burn the F/W (U12).
T70 TFT image and color error
Main Board
A. Check U7 to see if there is any cold or hollow soldering and reverse soldering of
IC or parts missing. Rule out the problem.
B. Check devices after CVBS signal to see if there is any cold or hollow
soldering and reverse soldering of IC or parts missing.
C. Measure the voltages of VGH VGL VLC to see if they are correct.
D. Check U17 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
E. Check Y1 to see if there is any cold or hollow soldering andreverse soldering
of IC or parts missing.
F. If the above actions are not working, replace the Main Board.
T71 TFT image is black and white
Main Board
A. Check U7 to see if there is any cold or hollow soldering andreverse soldering of
IC or parts missing. Rule out the problem.
B. Check devices after CVBS signal to see if there is any coldor hollow
soldering and reverse soldering of IC or parts missing.
C. Measure the voltages of VGH VGL VLC to see if they are correct.
D. Check U17 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
E. Check Y1 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
- 28 -
F. If the above actions are not working, replace the Main Board.
T72 TFT image shakes or is distorted
Main Board
A. Check U7 to see if there is any cold or hollow soldering and reverse soldering of
IC or parts missing. Rule out the problem.
B. Check devices after CVBS signal to see if there is any coldor hollow
soldering and reverse soldering of IC or parts missing.
C. Measure the voltages of VGH VGL VLC to see if they are correct.
D. Check U17 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
E. Check Y1 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
F. If the above actions are not working, replace the Main Board.
T73 TFT PAL color strip
Main Board
A. Measure the voltages of VGH,VGL,VLC to see if they are correct.
B. Check U17 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
C. Check the devices surrounding U7 and U11 to see if there is any cold or
hollow soldering and reverse soldering of IC orparts missing.
D. Check Y1 to see if there is any cold or hollow soldering and reverse soldering
of IC or parts missing.
E. If the above actions are not working, replace the Main Board.
T74 TFT ripple
Main Board
A. Check the the LED back-light board to see if it's connected to GND.
B. Check the 3-pin cable connected to the LED back-light boardto see if there
is any problem of plugging. Rule out the problem.
C. If the above actions are not working, replace the Main Board.
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