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ADJUSTMENT

- 17 -

GENERAL INFORMATION

All adjustment are thoroughly checked and corrected
when the monitor leaves the factory, but sometimes
several minor adjustment may be required. 
Adjustment should be following procedure and after
warming up for a minimum of 30 minutes. 

• Alignment appliances and tools.

- IBM compatible PC.
- Programmable Signal Generator. 

(eg. VG-819 made by Astrodesign  Co.)

- E(E)PROM with each mode data saved. 
- Alignment Adaptor and Software.
- Digital Voltmeter.
- White Balance Meter.
- Luminance Meter.
- High-voltage Meter.

AUTOMATIC AND MANUAL DEGAUSSING

The degaussing coil is mounted around the CRT so that
automatic degaussing when turn on the monitor. But a
monitor is moved or faced in a different direction, become
poor color purity cause of CRT magnetized, then press        

(DEGAUSSING)  on the OSD menu.

ADJUSTMENT PROCEDURE & METHOD

Install the cable for adjustment such as Figure 1 and run 

the alignment program on the DOS for IBM compatible PC. 

Set external Brightness and Contrast volume to max position.

1. Adjustment for BVoltage.

1) Display cross hatch pattern at Mode 4.
2) Adjust C951 + voltage to 160±0.5Vdc with VR901.

2. Adjustment for High-Voltage. 

1) Display cross hatch pattern at Mode 4.
2) Adjust FBT Anode voltage to 141± 0.5Vdc with

VR701.

5. Adjustment for Factory Mode (Preset Mode).

1) Display cross hatch pattern at Mode 1.
2) Run alignment program for MB776B on the IBM

compatible PC.

3) COMMAND 

START 

Y(Yes) command.

4) DIST. ADJ. 

TILT command. 

5) Adjust tilt as arrow keys to be the best condition.
6) DIST. ADJ. 

BALANCE command.

7) Adjust balance of side-pincushion as arrow keys to

be the best condition. 

8) DIST. ADJ.

FOS. ADJ

Mode No.

1 command.

9) Adjust V-SIZE as arrow keys to 230±2mm.
10) Adjust V-POSITION as arrow keys to center of the

screen.

11) Adjust H-SIZE as arrow keys to 310±2mm.
12) Adjust H-POSITION as arrow keys to center of the

screen.

13) Adjust S-PCC (Side-Pincushion) as arrow keys to

be the best condition.

14) Adjust TRAPEZOID as arrow keys to be the best

condition.

15) Display from Mode 2 to Mode 7 and repeat above

from number 9) to 14).

16) PRESET EXIT

→ 

Y(Yes) command.

6. Adjustment for White Balance and Luminance.

1) Set the White Balance Meter.
2) Press the       (DEGAUSSING) on the OSD menu for

demagnetization of the CRT.

3) Display color 0,0 pattern at Mode 4.
4) COLOR ADJ.

→ 

LUMINANCE command of the

alignment program.

5) Set Brightness and Sub-Brightness to max position.
6) COLOR ADJ.

→ 

BIAS ADJ.

→ 

COLOR NO.

→ 

1

command of the alignment program.

7) Check whether blue color or not at R-BIAS and G-

BIAS to min position and adjust B-BIAS to
0.3±0.05FL of the raster luminance.

8) Adjust R-BIAS

and G-BIAS

command to

x=0.281±0.01 and y=0.311±0.01 on the White
Balance Meter with PC arrow keys.

9) Adjust SUB-BRIGHT command to 0.4±0.1FL of the

raster luminance.

10) Display color 15,0 box pattern (70x70mm) at Mode 4.
11) DRIVE ADJ

→ 

No 1. command.

12) Set Contrast and Sub-Contrast to max position. 
13) Set B-DRIVE to 2/3 150(96 decimal) position at

DRIVE of the alignment program.

14) Adjust R-DRIVE and G-DRIVE command to white

balance x=0.283±0.001 and y=0.298±0.001 on the
White Balance Meter with PC arrow keys.

15) Adjust Sub-Contrast command to 54±2FL(MPR),

46±2FL(TCO) of the raster luminance.

16) Save in COLOR 1.

Summary of Contents for STUDIOWORKS

Page 1: ...SERVICE MANUAL LG STUDIOWORKS 77M MODEL ...

Page 2: ...Speaker Impedance 4Ω 3 5 Speaker Type Dome Bassreflex Closed 4 POWER SUPPLY 4 1 Power Range AC 100V 240V Free Voltage 50 60Hz 2 3A Max 4 2 Power Consumption 5 DISPLAY AREA 5 1 Active Video Area 310 x 230 mm 12 20 x 9 06 5 2 Display Color Full Colors 5 3 Display Resolution 1024 Dots x 768 Lines 85Hz 1280 Dots x 1024 Lines 60Hz 5 4 Video Bandwidth 110 MHz 6 ENVIRONMENT 6 1 Operating Temperature 15 C...

Page 3: ...K MIC OUT AUDIO IN AUDIO SPEAKER SPEAKER FBT VR701 VR901 Ref No SW201 VR201 VR202 SW206 SW205 Control Function POWER SWITCH CONTRAST CONTROL BRIGHTNESS CONTROL SOUND MUTE SOUND No 1 2 3 4 5 No 6 7 8 9 10 Ref No SW202 SW204 SW203 VR701 VR901 Control Function ENTER BUTTON OSD SELECT RIGHT OSD SELECT LEFT H V ADJUSTMENT B ADJUSTMENT ...

Page 4: ...dition 6 DIST ADJ BALANCE command 7 Adjust balance of side pincushion as arrow keys to be the best condition 8 DIST ADJ FOS ADJ Mode No 1 command 9 Adjust V SIZE as arrow keys to 230 2mm 10 Adjust V POSITION as arrow keys to center of the screen 11 Adjust H SIZE as arrow keys to 310 2mm 12 Adjust H POSITION as arrow keys to center of the screen 13 Adjust S PCC Side Pincushion as arrow keys to be t...

Page 5: ... must be ON F F A A B B C C 15 10 5 5 6 9 1 1 1 14 13 25 6 5V 5V 5V 4 7K 4 7K 4 7K 74LS06 74LS06 OFF ON OFF ON 11 17 Display color 15 0 full white patten at Mode 4 18 COLOR ADJ LUMINANCE ABL command 19 Adjust ABL to 35 1FL MPR 30 1 TCO of the luminance 20 Exit from the program Note Color mode 2 data is automatically save in the EEPROM by the microprocessor 7 Adjustment for Focus 1 Display H charac...

Page 6: ...USE F901 TROUBLE IN IC901 IC902 TROUBLE IN D920 D922 D923 D924 D926 TROUBLE IN IC923 IC925 Q922 Q923 Q924 Q926 CHECK FUSE OK CHECK C907 VOLTAGE AC120V 170VDC AC220V 310VDC NO YES YES YES YES NO NO NO CHECK IC901 PIN 3 WAVEFORM SQUARE WAVE COMES OUT CHECK D920 D922 D924 D923 D926 VOLTAGE 1 NO POWER ...

Page 7: ... 1 3 5 CHECK IC303 PIN 6 70V 10 12V TROUBLE IN P302 12V LINE IC304 TROUBLE IN PC SIGNAL P301 SIGNAL CABLE TROUBLE IN IC302 TROUBLE IN P302 12V LINE 70V LINE TROUBLE IN IC303 NO YES NO NO YES YES YES YES NO NO CHECK R G B CATHODE VOLTAGE TROUBLE IN R338 R341 R344 R345 L302 L304 D307 D310 D312 D313 TROUBLE IN CRT SOCKET YES NO ...

Page 8: ...ICATOR ON CHECK POWER INDICATOR GREEN or ORANGE CHECK D712 ANODE 120V CHECK G1 VOLTAGE 10 20V TROUBLE IN D712 TROUBLE IN D926 Q925 6 3V TROUBLE IN Q801 Q806 DPM MODE NO H and or V SYNC ORANGE NO GREEN YES YES NO 3 NO RASTER ...

Page 9: ... VERTICAL LINE CHECK Q706 CHECK B VOLTAGE 160V CHECK T701 FBT PIN 3 31KHZ 70V 69KHZ 140V CHECK Q705 COLLECTOR WAVEFORM TROUBLE IN Q706 TROUBLE IN 160V LINE TROUBLE IN Q717 Q718 Q719 D707 TROUBLE IN Q705 TROUBLE IN T701 P701 NO NO YES YES YES YES NO NO ...

Page 10: ...C401 PIN 18 19 20 CHECK Q711 Q716 CHECK L703 TROUBLE IN IC401 MICOM TROUBLE IN Q711 Q716 TROUBLE IN L703 TROUBLE IN L720 R744 NO NO NO YES YES YES Cs SIGNAL TABLE HORIZONTAK FREQUENCY fH 30K 39K 39K 47 5K 47 5K 62K 62K 70K Cs0 L L L H Cs1 L L H H Cs2 L H H H ...

Page 11: ...FLECTION ONE HORIZONTAL LINE CHECK IC601 PIN 3 15V CHECK IC601 PIN 7 40V CHECK IC701 PIN 12 13 TROUBLE IN R603 Q601 Q603 15V LINE TROUBLE IN HIGH VOLTAGE OUT CIRCUIT D713 TROUBLE IN IC701 TROUBLE IN IC601 V CIRCUIT NO NO YES YES YES NO 3V ...

Page 12: ...01 PIN8 V FBP T701 40V LINE TROUBLE IN IC302 IC301 TROUBLE IN IC301 IC302 NO YES DC 5V YES YES YES NO NO NO Pin 5 5V Pin 10 5V H V 5V H V CHECK IC301 B CHECK IC311 PIN 12 WAVEFORM ENTER BUTTON MUST BE PRESSED 7 TROUBLE IN OSD CHECK IC301 PIN 5 10 WAVEFORM CHECK IC311 PIN 13 14 15 ...

Page 13: ... GOING INTO DPM OFF MODE TROUBLE IN X401 TROUBLE IN IC401 MICOM TROUBLE IN Q922 Q923 Q925 Q926 TROUBLE IN PC OFF MODE FAILURE INPUT H V SYNC SIGNAL NO H V SYNC NO OFF MODE NO NO NO DPMF 0V DPM TABLE Mode Item NORMAL STAND BY SUSPEND OFF DPMS H H H L LED GREEN ORANGE ORANGE ORANGE DPMF H L L L YES SEE DPM TABLE YES YES 5V 6MHz 8 TROUBLE IN DPM ...

Page 14: ...VOLTAGE CHECK P902 P903 CHECK RL901 TROUBLE IN IC401 MICOM TROUBLE IN Q921 TROUBLE IN P902 P903 TROUBLE IN RL901 TROUBLE IN TH902 DEGAUSSING COIL NO DEGAUSSING DC 5V NO NO NO NO YES YES YES YES DEGAUSS ON THE OSD MENU MUST BE PRESSED 9 NO DEGAUSSING ...

Page 15: ...ATION NO TILT NO ROTATION TROUBLE IN IC401 MICOM TROUBLE IN 15V LINE 6 3V LINE TROUBLE IN Q501 Q503 TROUBLE IN P501 TILT COIL NO YES YES YES CHECK 15V LINE AND 6 3V LINE CHECK Q503 EMITTER VOLTAGE NO NO CHECK Q504 WAVE FORM ...

Page 16: ... 29 11 TROUBLE IN AUDIO TROUBLE IN SPEAKER P3 P4 P801 P802 JA802 NO AUDIO NO SOUND TROUBLE IN JA804 P1 TROUBLE IN IC1 CHECK IC1 PIN 7 8 AUDIO SIGNAL NO INPUT WAVEFORM YES YES CHECK IC2 PIN 2 10 NO 2Vp p ...

Page 17: ...1 Dynamic Focus Circuit Auto Beam Limit Vertical Blanking Brightness Control 120V 40V 6 3V D D Feed Back 30V 15V MICOM IC401 SCL SDA H V Sync PWM Control Sig 12V 15V 160V DY CDT Heater 6 3V I2C I2C I2C H V Sync G1 Screen Dynamic Focus Static Focus H V R G B Bias R G B Contrast H DRV B DRV B 15V TILT COIL DEGAUSSING COIL I2C VOLTAGE FEEDBACK 12V I2C 9V 15V SOUND REGULATOR Q1 AUDIO IN MIC OUT TO PC ...

Page 18: ...uishes polarity and frequency of H and V sync 3 The Micom sets operating mode and offers the controlled data H size H position V size etc 4 The controlled data of each mode is stored in itself 5 User can adjust screen condition by each OSD function The data of the adjusted condition is stored in EEPROM IC402 6 Users can control screen condition by the OSD Select Right Left Audio Audio Mute buttons...

Page 19: ...ve pulse to the G1 of the CRT And Brightness circuit is used for control of the screen brightness by changing DC level of the G1 17 Image Rotation Tilt Circuit This circuit corrects the tilt of the screen by supplying the image rotation signal to the tilt coil which is attached near the deflection yoke of the CRT 18 Video Pre Amp Circuit This circuit amplifies the analog video signal from 0 0 7V t...

Page 20: ......

Page 21: ...WIRING DIAGRAM 11 TH901 Signal Cable AC Socket P702 P804 P803 P802 P801 P405 P403 WG2 P402 S S P501 P805 P201 P202 P304 P302 P301 P303 P2 P3 P4 P1 P701 MIC SPEAKER SPEAKER P904 P704 P703 ...

Page 22: ...CDT EARTH DEGAUSSING COIL FBT PLATE HEAT SINK FOR Q719 FILTER AC SOCKET PLATE HEAT SINK FOR IC901 PLATE HEAT SINK FOR IC601 COMPRESS HEAT SINK FOR D704 Q709 Q706 PCB ASS Y CONTROL SUB TOTAL TCO 95 PCB ASS Y CONTROL SUB TOTAL MPR II BRACKET SIGNAL KNOB CONTROL ROTARY BRACKET VOLUME TCO 95 BRACKET VOLUME MPR II BRACKET MAIN TCO 95 BRACKET MAIN MPR II PCB ASS Y AUDIO TCO 95 PCB ASS Y AUDIO MPR II BRA...

Page 23: ... 34 7 AUDIO BOARD Component Side 8 AUDIO BOARD Solder Side ...

Page 24: ... 33 5 CONTROL BOARD Component Side 6 CONTROL BOARD Solder Side ...

Page 25: ... 32 3 VIDEO BOARD Component Side 4 VIDEO BOARD Solder Side ...

Page 26: ...CHASSIS ASSEMBLY REMOVAL 1 Disconnect P901 Degaussing pin P701 H DY pin and P601 V DY pin 2 Remove two screws a from the Main Bracket to separate it from the Front Cabinet 4 CRT BOARD ASSEMBLY REMOVAL 1 Remove three pins a 2 Remove the CRT ground connector b 3 Carefully separate the CRT Board Assembly from the CRT neck 4 Discharge the remaining static electricity by shorting between the Anode Cap ...

Page 27: ...REMOVAL 1 Remove eight screws a 2 Remove the Bottom Bracket 6 MAIN BOARD ASSEMBLY REMOVAL 1 Remove ten screws a 2 Remove three screws b 3 Release two latches c from the Main Board Assembly b a c c Bottom Bracket a a a a a a ...

Page 28: ...5 11 178 0 577 0 018 0 056 0 503 800 x 600 85Hz Yes MODE 4 68 677 14 561 10 836 3 725 0 508 1 016 2 201 85 00 11 764 11 182 0 582 0 014 0 044 0 524 1024 x 768 85Hz Yes MODE 5 31 47 31 78 25 42 6 36 0 64 3 81 1 91 70 08 14 269 12 712 1 557 0 414 0 063 1 080 640 x 400 70Hz Yes MODE 6 31 47 31 78 25 42 6 36 0 64 3 81 1 91 59 94 16 684 15 254 1 430 0 318 0 063 1 049 640 x 480 60Hz Yes MODE 7 37 88 26 ...

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