LG M1921a Service Manual

							LIPS Board Block Diagram
- 11 -
EMI
COMPONENTS
LINE
100 ~ 240V
INPUT RECTIFIER
AND FILTERENERGY
TRANSFEROUTPUT RECTIFIER
AND FILTER
15V
5V
GND
SIGNAL
COLLENT-
IONPHOTO-
 COUPLER
ISOLATI ON
HVD C10 0KHz
PRIMARY SECONDA RY
50 ~ 60 Hz
PWM
COMTROL
CIRCUIT
Operation description_LIPS
1. EMI components. 
This part contains of EMI components to comply with global marketing EMI standards like FCC, VCCI, CISPR, the
circuit included a line-filter, across line capacitor and of course the primary protection fuse.
2. Input rectifier and filter.
This part function is for transfer the input AC voltage to a DC  voltage through a bridge rectifier and a bulk capacitor.
3. Energy Transfer. 
This part function is for transfer the primary energy to secondary through a power transformer.
4. Output rectifier and filter. 
This part function is to make a pulse with modulation control and to provide the driver signal to power switch, to adjust
the duty cycle during different AC input and output loading condition to achieve the DC output stabilized, and also the
over power protection is also monitor by this part.
5. Photo-Coupler isolation.
This part function is to feed back the DC output changing status through a photo transistor to primary controller to
achieve the stabilized DC output voltage.
6. Signal collection.
This part function is to collect the any change from the DC output and feed back to the primary through photo
transistor. 
						

							EDID ADJUSTMENT
- 12 -
Windows EDID V1.0 User Manual
Operating System: MS Windows 98, 2000, XP
Port Setup: Windows 98 => Don’t need setup
Windows 2000, XP => Need to Port Setup.
This program is available to LCD Monitor only.
1. Port Setup
a) Copy “UserPort.sys” file to   
“c:\WINNT\system32\drivers” folder
b) Run Userport.exe
c) Remove all default number
d) Add 300-3FF
e) Click Start button.
f) Click Exit button.2. EDID Read & Write
1) Run WinEDID.exe  
2) Edit Week of Manufacture, Year of Manufacture, 
Serial Number
a) Input User Info Data
b) Click “Update” button
c) Click “ Write” button
※ ※
If you dont write EDID, check below
1. Enter SVC Menu (refer 14page)
- Enter Etc
- Enter Write Protect
1 : EDID protection (No write)
0 : EDID wirte
- Write EDID
2. Escape  SVC Menu and push In-stop Button on SVC-Remote controller. 
						

							- 13 -
220
IBM
Compatible PC
PARALLEL PORT
Power inlet (required)
Power LED
ST SwitchPower Select Switch
(110V/220V)
Control Line
Not usedRS232C PARALLEL
V-SYNCPOWER
ST
VGSMONITOR
E
E
V-Sync On/Off Switch
(Switch must be ON.)F
F
A
A
BB
C
C
15
10
556 9
11
1
14 13
25 6
5V
5V5V
4.7K
4.7K
4.7K
74LS0674LS06 OFF ON
OFFON
11
RGB(PC/DTV) INANTENNA INAUDIO
(RGB) INH/P S-VIDEO
AV IN 2 AV 1(Mono)VIDEOAUDIOLR
Video Signal
Generator
Figure 1. Cable Connection 
						

							ADC ADJUSTMENT
- 14 -
1. DCXO setting in Video (AV2) 
■Convert to AV2 in Input-source
■Signal equipment display
Output Voltage : 700 mVp-p
Impress Resolution : NTSC J (Model No.207 at MSPG925L)
Pattern : Color Bar (Pattern No.33 ant MSPG925L)
1) IN-START selection of Service Remote Controller
2) OPTION4 Selection
3) Right button selection in DCXO-AUTO(AV2). 
Then, DCXO-AUTO may change from 0 to 1.
4) DCXO value confirmation 
(Exit and Enter again Option4 _ Menu+Option4 selection)
2. Video (AV2) input ADC
■Signal equipment display
Output Voltage : 700 mVp-p
Impress Resolution : NTSC J (Model No.207 at MSPG925L)
Pattern : Gray pattern that left & right is black and center is white signal.
(Pattern No.29 ant MSPG925L)
1) IN-START selection of Service Remote Controller
2) AUTOADC Selection
3) Right button selection in Auto Gain.
Then, Value of Offset and Gain may change.
Service Menu
Auto ADC
Reserved Option 1
Option 2
Option 3
Reset All
XXXX. XX. XX
NTSC - XX
LOC Ver XX. XX. XX
Sedna Ver XX. XX. XX
24 NG
Option 4
DCXO NGBRIFE NGHD NGAV N G
Option 4
DCXO 60
0
1
1
195
0
1
1 UART Mssg. ON DCXO-AUTO(AV2)
EEPROM WP
IIC-SW
2 Hours Off Opt.
(AUTHOR)
Sedna-Lee K.W.
Lee J.U.
Jang H.B.
Kim S.K. UOC-Park K.W. BL-ADJ
New Sawfilter
Service Menu
Auto ADC
Reserved Option 1
Option 2
Option 3
Reset All
XXXX. XX. XX
NTSC - XX
LOC Ver XX. XX. XX
Sedna Ver XX. XX. XX
24 NG
Option 4
DCXO NGBRIFE NGHD NGAV N G
Auto Gain
BRIFE
Green Gain BRIFE - USA
BRIFE - KOR
Blue Gain
Red Offset
Green Offset
Blue Offset Red Gain00
00 00
00
00
00
00
00 00
DCXO Adjustment Pattern (No.33)
Service Main Menu Option 4 Menu
(700mVp-p)
ADC Adjustment Pattern (No.29)
Service Main MenuAuto Gain 
						

							- 15 -
3. RGB-PC input ADC
■Signal equipment display
Output Voltage : 730 mVp-p
Impress Resolution : SXGA (Model No.45 at MSPG925L)
Pattern : Gray pattern that left & right is black and center is white signal
(Pattern No.28 ant MSPG925L)
1) If Source change from AV2 to RGB-PC, Monitor executes auto intelligent.
Do not ADC In this condition.
2) Execute ADC after AC power off/on.
3) IN-START selection of Service Remote Controller
4) AUTOADC Selection
5) Right button selection in Auto Gain
Then, Value of Offset and Gain may change.
Service Menu
Auto ADC
Reserved Option 1
Option 2
Option 3
Reset All
XXXX. XX. XX
NTSC - XX
LOC Ver XX. XX. XX
Sedna Ver XX. XX. XX
24 NG
Option 4
DCXO NGBRIFE NGHD NGAV N G
Auto Gain
BRIFE
Green Gain BRIFE - USA
BRIFE - KOR
Blue Gain
Red Offset
Green Offset
Blue Offset Red Gain00
00 00
00
00
00
00
00 00
(730mVp-p)
ADC Adjustment Pattern (No.28)
Service Main MenuAuto Gain
SERVICE OSD
Service Menu
Auto ADC
Reserved Option 1
Option 2
Option 3
Reset All
200X. 0X. 0X
NTSC - XX0X. 0X
LOC Ver X. XX. XX
Sedna Ver X. XX. XX. XX
Option 4
■Description of operation
- Auto ADC : Adjust Auto ADC and Adjust RGB Gain/Offset
- Option 1 : Adjust Tuning
- Option 2 : Adjust Sound
- Option 3 : Adjust Country, Language
- Option 4 : Adjust etc..
- Reset All : Default setting 
						

							TROUBLESHOOTING GUIDE
- 16 -
No power 
(LED indicator off)
Check short of main B/D 
or Change Lips
Change U406
Change LED Assy
Check 15V or 5V 
of Lips
Check Output of 
U406
Check LED Assy
Check J103, J125, J126
Connector 
Fail
Fail
Change Q402Check Output of 
Q402
Fail
Pass
Pass
Fail
Pass
Pass
Pass
:[A]Process 
						

							- 17 -
No Raster
Check LED Status 
on display unit
Check the input/
Output of U301
Check 
U402, U403, U406
Check inverter
Connector or inverter
Check input source cable and jack
Repeat A PROCESSFail
Change U402, U403,
U406
Fail
Change U301Fail
Change inverter
connector or inverter
Fail
Change panel link
cable or module
Fail Check panel link 
Cable or module
Pass
Pass
Pass
Pass
Pass
:[B]Process 
						

							- 18 -
No Raster on AV Signal
(CVBS, S-VHS)No Raster on TV(RF) signal
Change L109, L110, L112 
R194, R198, R184Check the signal of 
L109, L110, L112
R194, R198, R184
Repeat
[A] Process Check the output of 
TU701
Check the
input/output  of U301
Check the 
input/output of U101
Check input source cable and
jack 
Fail
FailFail
Fail
Re-soldering or
Change the defect part
Check X301
Fail
Re-soldering or
Change the defect part
Check 5V, 33V of TU701
Re-soldering or 
Change the defect part
TN200
(TUNER PACK ASSY)
Pass
Pass
Pass
Pass
Pass 
						

							- 19 -
No Sound
Check the speaker wire
Change source inputCheck the 
input source
Fail
Pass
Pass
Pass
Pass
Re-soldering or 
Change the defect part
Check X301Check the input/output 
of U301
Fail
Re-soldering or 
Change the defect partCheck the input/output 
of U201
Fail
Change speakerCheck the speakerFail 
						

							WIRING DIAGRAM
- 20 -
30P
6631T11016M
5P11 P
6631T20038G
6631900042B
EAB32761501
3P
6631900024D