Dynex DX-LTDVD20 User manual

SERVICE MANUAL
MODEL
DX-LTDVD20
CAUTION : Before servicing this chassis, read the "IMPORTANT SERVICE SAFETY INFORMATION" section
on page 2 of this manual.
FILE : e15257f
DATA : Sep. 29 2007

TABLE OF CONTENTS
TABLE OF CONTENTS...............................................................................................2
IMPORTANT SERVICE SAFETY INFORMATION......................................................3,4
GENERAL SPECIFICATIONS ....................................................................................5-7
DISASSEMBLY INSTRUCTIONS................................................................................8
ISP INSTRUCTION .....................................................................................................9,10
ELECTRICAL ADJUSTMENTS..................................................................................11-12
TROUBLESHOOTING GUIDE....................................................................................13-21
BLOCK DIAGRAMS....................................................................................................22-24
PRINTED CIRCUIT BOARDS......................................................................................26-27
SCHEMATIC DIAGRAMS............................................................................................28-39
INTERCONNECTION DIAGRAM.................................................................................40
WAVEFORMS..............................................................................................................41-42
MECHANICAL EXPLODED VIEWS............................................................................43
MECHANICAL REPLACEMENT PARTS LIST...........................................................44
ELECTRICAL REPLACEMENT PARTS LIST............................................................45-57
WIRING CONNECTION ..............................................................................................25
2

Whenthepowersupplyisbeingturnedon,youmaynotremovethislasercautionslabel.Ifitremoves,radiationoflaser
maybereceived.
LASERBEAMCAUTIONLABEL
PREPARATIONOFSERVICING
PickupHeadconsistsofalaserdiodethatisverysusceptibletoexternalstaticelectrocity.
Althoughitoperatesproperlyafterreplacement,ifitwassubjecttoelectrostaticdischargeduringreplacement,
itslifemightbeshortened.Whenreplacing,useaconductivemat,solderingironwithgroundwire,etc.to
protectthelaserdiodeformdamagebystaticelectricity.
Andalso,theLSIandICaresameasabove.
Solderingiron
withgroundwire
orceramictype
Groundconductive
wriststrapforbody.
Conductivemat
Thegroundresistance
betweenthegroundline
andthegroundislessthan10
1M
3

SAFTY NOTICE
Plug the AC line cord directly into a 120V AC outlet (do
not use an isolation transformer for this check). Use an
AC voltmeter, having 5000 per volt or more sensitivity.
Connect a 1500 10W resistor,paralleled by a 0.15uF
150V AC capacitor between a knomn good earth ground
(water pipe, conduit, etc.) and all exposed metal parts of
cabinet (antennas, handle bracket, metal cabinet
screwheads, metal overlays, control shafts, etc.).
SAFTY PRECAUTIONS
LEAKAGE CURRENT CHECK
Measure the AC voltage across the 1500 resistor.
The test must be conducted with the AC switch on and
then repeated with the AC switch off. The AC voltage
indicated by the meter may not exceed 0.3V.A reading
exceeding 0.3V indicates that a dangerous potential
exists, the fault must be located and corrected.
Repeat the above test with the LCD TV power plug
reversed.
NEVER RETURN A LCD TV TO THE CUSTOMER
WITHOUT TAKING NECESSARY CORRECTIVE
ACTION.
READING SHOULD NOT EXCEED 0.3V
LCD TV
AC OUTLET
AC VOLTMETER
Test all exposed metal.
Voltmeter Hook-up for Leakage Current Check
0.15uF 150V AC
1500
10W
(5000 per volt
or more sensitivity)
Good earth ground
such as a water pipe,
conduit, etc.
The lightning flash with arrowhead symbol, within an
equilateral triangle, is intended to alert the user to the
presence of uninsulated "dangerous voltage" within the
product's enclosure that may be of sufficient magnitude to
constitute a risk of electric shock to persons.
The exclamation point within an equilateral triangle is
intended to alert the user to the presence of important
operating and maintenance (servicing) instructions in the
literature accompanying the appliance.
4

GENERAL SPECIFICATIONS
G-1 TV LCD LCD Size / Visual Size 20 inch
System LCD Type Color TFT LCD
Number of Pixels 1366(H)×768(V)
View Range Left/Right/Up/Down
Color System NTSC
Speaker 2 Speaker 8ohm
Sound Output Max 3W×2
G-2 DVD System Color System NTSC
Disc
Disc Diameter 120mm/90mm
G-3 Tuning Broadcasting System
System Tuner System
G-4 Signal Video Signal Input Level 1VPP
Output Level
RGB Signal Output Level NO
Audio Signal Input Level 2V
Output Level at DVD 2V
at TV ≥500mV
Digital Output Level 500mV±100mV
G-5 Power Power Source AC 100～240V , 50/60Hz
Power Consumption at AC ≤80W(Max)
Stand by (at AC) ≤1W
G-6 Temperature Operation ﹢5℃～﹢35℃
Storage ﹣20℃～﹢60℃
G-7 Operating Humidity Less than 80％RH
G-8 Timer Sleep Timer Max Time 120 minutes
Step 0-15-30-45-60-90-120
G-9 Remote Unit RC260
Control Power Source Voltage(D.C) 3V(60)
G-10 Features Auto Shut Off YES
(TV) Auto Search YES
Power On Memory YES
Comb Filter 2D
Auto Setup(Language/CH Program) NO
Picture Setting(TV) Mode(Picture Preference) YES
Brightness , Contrast , Color YES
Tint NO
Sharpness YES
Color Temperature YES
Cable Clear
Picture Setting(PC) BRIGHTNESS , CONTRAST YES
HOR POSITION , VER POSITION YES
PHASE , CLOCK YES
AUTO ADJUST NO
RED , GREEN , BLUE YES
Audio MTS YES
Tone Control (Bass/Treble/Balance) YES
Stable Sound NO
Surround NO
BBE NO
5

SRS WOW (SRS 3D/Focus/Tru Bass) NO
Variable Audio Out YES
Tuning CH Program
TV/Cable YES
ADD/DELETE
Label CH Label
Video Label
Favorite CH YES
V-Chip V-chip 2.0
Type
OSD Language
Closed Caption YES
CC Advanced YES
Picture Size 4:3 16:9
Picture Scroll NO
Cinema Mode YES
Aspect 16:09
Backlight YES
Freeze frame YES
PIP/POP NO
PC Monitor Input VGA (640x480)/60 YES
VGA (720x400)/72 YES
WVGA (848x480) NO
SVGA (800x600)/60 YES
XGA (1024x768)/60 YES
WXGA (1280x768)/60 YES
WXGA (1280x720)/60 YES
WXGA (1360x768)/60 YES
SXGA (1280x1024) NO
HDMI Input VGA (640×480) YES
720×480i (4:3) YES
720×480i (16:9) YES
720×480p (4:3) YES
720×480p (16:9) YES
720×576i (4:3) YES
720×576i (16:9) YES
720×576p (4:3) YES
720×576p (16:9) YES
1280×720p YES
1920×1080i YES
Component Input 720×480i (4:3) YES
720×480i (16:9) YES
720×480p (4:3) YES
720×480p (16:9) YES
720×576i (4:3) YES
720×576i (16:9) YES
720×576p (4:3) YES
720×576p (16:9) YES
1280×720p YES
1920×1080i YES
Features Tray Lock
(DVD) MP3 Playback YES
Divx Playback NO
English / French / Spanish
6

DMF Support NO
JPEG YES
WMA NO
Digital Out (Dolby Digital) NO
(MPEG) NO
(PCM) NO
(DTS) NO
Down Mix Out (Dolby Digital) YES
(DTS) NO
Closed Caption YES
Screen Saver YES
Audio DAC YES
G-11 Accessories Owner's Manual Language
Remote Control Unit
Guarantee Card YES
Warning Sheet YES
Quick Set-up Sheet YES
Battery NO
UM size x pcs
OEM Brand
AC Adapter YES
AC Cord (for AC Adapter)
AV Cord (2Pin-1Pin)
Registration Card (NDL Card)
Earphone YES
300ohm to 75ohm Antenna Adapter
G-12 Interface Terminals Rear Video Input 1 YES
Audio Input 1 YES
S - Input 1 YES
Video Input 2 NO
Audio Input 2 NO
S- Input 2 NO
Video Output NO
Audio Output YES
Component Input YES
Analog Audio YES
HDMI Input YES
Analog Audio NO
PC Monitor Input YES
Analog Audio YES
Digital Audio Output YES
DC Jack NO
VHF/UHF Antenna Input YES
Other Terminal NO
AC Outlet NO
Side Video Input 2 YES
Audio Input 2 YES
PC Monitor Input(w/ Analog Audio L/R) NO
Other Terminal NO
G-13 Set Size Approx. W x D x H (inch) 209×166.1×82.7
w/o Handle, Stand Approx. W x D x H (inch) 209×145.2×35.4
7

DISASSEMBLY INSTRUCTIONS
4: MAIN PCB AND POWER PCB. (Refer to Fig. 4)
1.
2.
3.
Remove the screws.
Disconnect the connections.
Remove the Main PCB and Power PCB.
Fig. 4
2: BACK PANEL AND DVD (Refer to Fig. 2)
1.
2.
3.
4.
5.
Remove the screws .
Disconnect the connections.
Remove DVD.
Remove the screws .
Remove back panel.
Fig. 2
1: STAND (Refer to Fig. 1)
1.
2.
3.
4.
5.
Unlock the supports .
Remove the screws .
Remove stand.
Remove the screws .
Remove DVD cover.
Fig. 1
5: OPERATION PCB AND INPUT PCB AND HV POWER
PCB AND LCD PANEL AND SPEAKER.(Refer to Fig. 5)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Remove the screws .
Remove the Operation PCB and Input PCB.
Remove the screws .
Remove the LCD panel cover.
Remove the screws .
Remove the HV power PCB.
Remove the LCD panel.
Remove the screws .
Remove the Speaker.
Fig. 5
1
1
2
2
1
1
3
2
1
3
2
3: SHIELD COVER. (Refer to Fig. 3)
1.
2.
Remove the screws.
Remove the shield cover.
Fig. 3
1
2
3
4
1
2
3
4
8

ISP INSTRUCTION
5. Sure upgrade file read, Click "Auto" to enter next interface
(Refer to Fig. 4).
1. Connect one end of the Jig to the LPT jack of the computer, and the other
end to the VGA connector PC at the side of the TV.
3. Click "connect", if it clue to "Device Type is PM25LV040" mean connector
of upgrade fixture OK, if it clue to "Can't Entry ISP Mode!!", please secure
connection of Jig firmly, then click "connect", if it clue to " Device Type is
PM25LV040". (Refer to Fig. 2)
4. Click "Read" to enter next interface, Click "Read" to select upgrade file
(*.bin). (Refer to Fig. 3)
2. Run "ISP_Tool V4.0.1.exe"(Refer to Fig. 1)
6. Unselect "Program" and "Verify", click "Run" (Refer to Fig. 5).
7. If it clue to "Blank OK", unselect "Blank" and select "Program" and
"Verify", click "Run" to enter upgrade status (Refer to Fig. 6).
8. If it clue to "Program OK" and "Verify OK", it mean upgrade succeed
(Refer to Fig. 7).
9. If it clue to "Program Error" (Refer to Fig. 8), click "Run" to repeat
currently setp,title it clue to "Program OK" and "Verify OK"
(Refer to Fig. 7).
10. Click "DIS CON" to exit ISP upgrade program (Refer to Fig. 9).
Fig. 1
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 2
Fig. 3
Fig. 4
9

Turn on the power, and set the DVD mode.
Confirm that the "OPEN" will be appeared on the screen.
Insert the Up-Date Disc. Automatic read will start and "Upgrade file detected, Upgrade? Press PLAY key to start"
will be displayed on the screen.
Press PLAY button on the remocon to start upgrade.
NOTE: Do not turn off the unit on the way or operate the keys on the unit and remocon.
Up-Date error will happen and can not be done with the Up-Date of Up-Date Disc.
After the Up-Date, Logo screen will appear.
Unplug the AC cord, then plug it in.
CHECK FOR THE FIRMWARE VERSION
Turn on the power, and set the DVD mode.
Press "SETUP" "SUBTITLE" "1" "2" "3" button on the remote control. Firmware version will be displayed on the
top bottom of the screen.
Turn off the power
RE-WRITE FOR DVD FIRMWARE
1.
2.
3.
4.
5.
8.
9.
10.
11.
070123 13:55 SASn 4
Fixed
Release date (Example: 2007.1.23, 13:55)
When the changed version displays, the Re-write will be completed.
070123 13:55 SASn 4
10

ELECTRICAL ADJUSTMENTS
Press "INPUT+ 2 + 5 + 8 + 0" on the remote control in turn to enter Factory mode as FIG 1.
Press "left" or "right" to select "COMPONENT", "DVD", "VGA" items,
Press "up" or "down" to select "ADC ADJ." items. Example: FIG 2.
Press "up" or "down" to select "Auto Tune" items, Press "right" to "ADC ADJ." automatic adjustment.
Fig. 1
Fig. 2
Press "OK" on the remote control to finish the "ADC ADJ." automatic adjustment.
Press "OK" on the remote control to exit Factory mode.
INPUT SOURCE
ADC ADJ.
COLORTEMP ADJ.
PICTURE MODE
FACTORY RESET
USER RESET
SW Version 00:52:17 02/09/07
ExtMcu Version: B 24:60:00 12/06/06
DTV
Factory Menu For AU20_T200XW02
R Gain
G Gain
B Gain
R offset
G offset
B offset
Auto Tune
Patten: Y : 100IRE/ PbPr : 75IRE
Ex: 5 4200 SMTPE/COL_100_0/Shinco DemoDisc
0x81
0x3a
0x89
0x7f
0x7f
0x7f
ADC ADJ.
11

4. The STARTING SETUP feature appears. Setup your TV/DVD by the owner manual.
FIG. 1
1.
2.
3.
Turn POWER on.
Press "INPUT+ 2 + 5 + 8 + 0" on the remote control in turn to enter Factory mode as FIG 1.
Using the "up+ down"to select "FACTORY RESET", press "right"to automatic reset.
WHEN REPLACING EEPROM (MEMORY) IC
INPUT SOURCE
ADC ADJ.
COLORTEMP ADJ.
PICTURE MODE
FACTORY RESET
USER RESET
SW Version 00:52:17 02/09/07
ExtMcu Version: B 24:60:00 12/06/06
DTV
Factory Menu For AU20_T200XW02
12

TROUBLESHOOTING GUIDE
No work / LED is off
Replace Power PCB
Replace fuse and eliminate short
or open situation
Yes
Yes
Yes
Yes
No
No
No
No
Check if power
connection isnormal Replace power connection
Check if fuse is normal
Check if voltage of J8
pin4 is normal Replace Main PCB
Replace RMC PCB
Check if voltage of
Power PCB CZ2,
CZ3 is normal
13

TROUBLESHOOTING GUIDE
No work / LED is red
Replace U1,U3,U6,U25,U27
Yes
Yes
No
No
Check if RMC
PCB is normal Replace RMC PCB
Replace Main PCB
Check if voltage of U1,U3,
U6,U25,U27 is normal
14

TROUBLESHOOTING GUIDE
No TV Picture
Replace Main PCB
Yes
No
Check if voltage
of U38 pin17 is 5V
Replace U38 HF
No Picture / LED is blue
Yes
Yes
No No
Check if backlight is normal
Check the power and
control signal of CZ2
in main PCB is normal
Check if voltage of power
PCB CZ3 pin 13 is normal
Replace LCD panel
No
Replace Main PCB
Yes
Replace Main PCB
Yes
Yes
No
No
Check if connector
of CON10 is normal Replace CON10
Replace LCD panel
Check if signal of
LVDS is normal
15

TROUBLESHOOTING GUIDE
No CVBS/SVIDEO Picture
Yes
Replace Main PCB
Replace connect wire
No
Check if SVIDEO/CVBS
signal of U22 pin25,26,
29,30 is normal
No HDMI
Replace connection
Yes
Yes
No
Check if signal of
CON9 is normal
Replace U12 or U13
No
Check if voltage of
U13 pin8 is normal
Replace U9
Yes
No
Replace Main PCB
Check if signal of
U9 pin 124,125 is normal
16

TROUBLESHOOTING GUIDE
No DVD picture
Replace Main PCB
Yes
Yes
No
Replace DVD
Check if voltage of
J2 pin 1 is normal
Replace CONNECTION
No
Check if signal of
J2 pin 8,9,10 is normal
17

TROUBLESHOOTING GUIDE
No VGA picture
Replace connection
Yes
Yes
No
Replace Main PCB
Check if signal of CON7
pin 1,2,3,12,13,15 is normal
Replace U8
No
Check if volatge of
U8 pin 8 is normal
Yes
Replace Main PCB
No
Check if signal of U22 pin
7,8,33,34,55,56 is normal
Yes
Replace U22
No
Check if signal of
LVDS is normal
18

TROUBLESHOOTING GUIDE
No AV1/AV2 audio
Replace connection
Yes
No
Replace Speaker
Check if signal of CON3
pin 1,2 and CON4 pin
6,8 is normal
Replace U22
No
Check if signal of
U22 pin 79,80 is normal
Yes
Replace U32
No
Check if signal of
U32 pin 1,7 is normal
Yes
Replace U31
No
Check if signal of U31
pin 1,2,14,15 is normal
Yes
19

TROUBLESHOOTING GUIDE
No PC/HDMI audio
Replace U22
Yes
No
Replace Speaker
Check if signal of U22
pin 70,71,75,76 is normal
Replace U36
No
Check if signal of
U36 pin 1,7 is normal
Yes
Replace U31
No
Check if signal of U31
pin 1,2,14,15 is normal
Yes
20