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19-inch Color  Monitor
B1997PNST (MD 1998LE)

Service Manual

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Summary of Contents for B1997PNST

Page 1: ...19 inch Color Monitor B1997PNST MD 1998LE Service Manual R ...

Page 2: ...translated or converted to any electronic or machine readable form without prior written permission of LiteOn Technology Corp MD 1998LE B1997PNST Service Manual PrintedinTaiwan Trademarks LiteOn is a registered trademark of LiteOn Technology Corp All other trademarks are the property of their respective owners No Version Release Date Revision 1 1 0 Nov 21 2000 Original release ...

Page 3: ...recautions 2 2 Product Specifications 5 3 Operation Theory 9 4 Alignments and Adjustments 14 5 Troubleshooting 18 6 Recommended Spare Parts List 22 7 Block Diagram 24 8 Exploded Diagrams Inserted 9 PCB Diagrams Inserted 10 Schematic Diagrams Inserted ...

Page 4: ...d maximum rating never to exceed 1 1 2 Safety Checks Before returning the monitor to the user perform the following safety checks 1 Inspect to make certain that each lead dress is not pinched or that hardware is not lodged between the chassis and other metal parts in the monitor 2 Inspect all protective devices such as nonmetallic control knobs insulating materials cabinet backs adjustment and com...

Page 5: ...ving or installing any component or assembly disconnecting PCB plugs or connectors and connecting a test component in parallel with a capacitor 3 When replacing parts or circuit boards clamp the lead wires around the component before soldering 4 When replacing a high wattage resistor 0 5W metal oxide film resistor in the circuit board keep the resistor about 1 cm 1 2 inch away from the circuit boa...

Page 6: ... regular period 2 Test Setup a Test duration 3 seconds b Set current limit at 25 A c The grounding resistance must be less than 0 1 ohm 3 Test Procedure a Plug the monitor power cord to the tester terminals b Make sure all connections are well contacted c Turn on monitor power and tester power d Press Test button e If green light shows up means test OK If red light shows up means test fails f If t...

Page 7: ...e Sync horizontal vertical TTL positive or negative Synchronization Frequencies Horizontal 30 to 98 kHz Vertical 50 to 120 Hz Signal Connectors 15 pin D shell connector Video Signals Analog 0 7 Vp p RGB positive Power Input 150 Watts maximum PHILIPS CRT AC rated voltage 90VAC to 264VAC Misconvergence Center Area 0 2 mm Corner Area 0 35 mm User Controls Power On Off Contrast Brightness Horizontal S...

Page 8: ...gnal Cable Pin Assignment Pin Signal Pin Signal 1 Red video 9 5V from PC 2 Green video 10 Ground 3 Blue video 11 Ground 4 Ground 12 SDA 5 NC 13 H Sync 6 Red ground 14 V Sync 7 Green ground 15 SCL 8 Blue ground Note This pin is used for selftest detection Connect this pin to ground at the PC end ...

Page 9: ...g us 6 356 6 085 5 33 5 172 4 148 4 409 3 657 3 725 3 022 2 844 3 624 2 765 3 017 C Sync us 3 81 2 028 1 556 1 616 1 185 1 138 1 219 1 016 1 067 1 016 1 231 0 948 1 077 D B P us 1 907 3 042 2 22 3 232 2 37 2 702 2 235 2 201 1 837 1 422 2 12 1 501 1 508 E Active us 25 42 20 282 17 78 16 16 10 667 14 222 13 10 836 9 481 8 127 8 752 7 901 8 62 F F P us 0 636 1 014 1 556 0 323 0 593 0 569 0 203 0 508 ...

Page 10: ...ent Signal DPMS Table 2 3 Display Power Management Signal DPMS State LED Color H Sync V Sync Powe r Consumption ON Green Pulse Pulse Normal STANDBY Yellow No Pulse Pulse 15 watts SUSPEND Yellow Pulse No Pulse 15 watts OFF Amber No Pulse No Pulse 8 watts 2 5 TCO Version The monitor meets the energy saving electric and magnetic field requirements Also it is compliant with TCO 99 labelling scheme 2 5...

Page 11: ...l for Rotation and one F V for H frequency driver compensation Two I O s pin 27 28 are provided for I2C bus used for I502 MTV021N 21 on screen display 2 In addition the microcontroller offers Auto Mode detection via Hsync pin 41 and Vsync pin 42 inputs According to Auto Mode detection VESA DPMS power saving pin 29 30 will limit the output power under 15W for Standby or Suspend mode under 8W for OF...

Page 12: ...out2 can be directly coupled to the vertical deflection booster pin 1 and pin 2 of TDA8351 2 The TDA8351 has two output stages which are current driven in opposite phase and operate in combination with the deflection coil in a full bridge configuration 3 3 5 E W Trapezoid and H Size Controls 1 The B driver for step down circuit is from pin 6 it provides 20 80 duty cycle outputs according to H freq...

Page 13: ...ff modes The output voltage C810 is 180 V 380V DC and generated through input voltage C816 step up The maximum voltage is decided by R826 and R827 while the minimum voltage is decided by C817 In the meanwhile it will get a similiar to input voltage waveform of input current to acquire a good PF value 3 4 4 Power LED Status 1 The LED has 3 leads common cathode with green and amber color for differe...

Page 14: ...izontal free run frequency is about 62 kHz under override condition SMPS is synchronized to this frequency 3 4 8 O V P If the auxiliary voltage is higher than zener voltage ZD806 22 volts and makes pin 3 of I802 higher than 1 V pin 6 duty cycle is limited to have the OVP activated 3 4 9 O P P The excess current of T805 through R819 can develop enough voltage on pin 3 then limit the power delivered...

Page 15: ...743BSP preamplifier 2 The amplifier RGB signals 0 3 Vpp are adjusted by I2 C bus pin 19 is for clamp pulse which comes from pin 16 of TDA4856 to set up equal clamp level 3 The video output stages is I901 LM2402 the output resistors R904 R934 and R964 are 47 ohm R913 R943 and R973 are 56 ohm for arcing protection and the power dissipation is minimized 4 The RGB cathodes cut off are adjusted by D A ...

Page 16: ...alyzer II 5 Signal generator IBM PC with proper display cards or Chroma 2250 or equivalent 6 Screwdriver 4 1 3 Switching Power Supply and Regulator Adjustment a The regulated B control has been preset in the factory and needs no adjustment However if any repair is made on the power supply section the following readjustment procedures are recommended 1 Allow the monitor to warm up for about 15 minu...

Page 17: ... Select preset color then choose 9300 K 1 b Adjust Green cut off around 70 OSD step 1 c Adjust G1 and R B cut off to get 0 8 0 15 0 1 FL of raster light output 1 d Confirm x 283 5 y 297 5 CONDITION Display image 50 mm x 50 mm white block pattern PROCEDURE 2 a Set Brightness to mid level 2 b Adjust Contrast to maximum 2 c R B signal off and adjust green gain to get Y 25 0 2 FL 2 d R B signal on adj...

Page 18: ...CONDITION Display image Crosshatch pattern Warm up Time 30 minutes PROCEDURE 1 Set Brightness and Contrast to display a well defined pattern 2 Ensure the convergence magnet rings are correctly positioned on the CRT 3 Rotate the individual rings of 4 pole convergence magnets by changing the spacing between the 2 tabs to converge the vertical red and blue lines at the center of the screen 4 Rotate t...

Page 19: ...rea with a external degaussing coil 4 2 6 External Degaussing 1 Apply line voltage to the degaussing coil and move it in a rotary motion over the front sides and top of the monitor The coil should be kept away from the rear of the monitor to avoid damaging the magnetic neck components 2 Slowly rotate and move the coil away from the monitor to about 6 feet beyond the point where no effect on the CR...

Page 20: ...heater Grid 1 Grid 2 etc Check I401 ZD401 Q416 Q424 Check D801 Check I802 R894 R867 Q802 D820 D819 D822 D826 D824 D827 D831 ZD802 ZD803 Yes Short Circuit at load Check DC B line F801 Yes Check AC I P on T805 No No T101 pin 2 HV B Yes Video High 50 V or more 0 V Yes 0 V HIGH 48 V Normal 40 V 31 5 kHz I103 I102 Q103 Q104 R8A3 I103 Check I401 Q424 Q416 D409 ...

Page 21: ...ction Key Abnormal Repair power supply Replace X701 Yes Check 5V from I810 regulator Power ON OFF again and check X701 oscillator OK Function Key Abnormal No No No Replace I701 Yes Check LED LD701 OK Replace Q701 or Q702 No Yes Check I701 uC OK Yes END ...

Page 22: ...ontal line Replace I301 Check pin 12 pin 13 waveform at I401 Yes Check voltage of pin 3 at I301 about 17 3 V Check pin 4 or pin 7 waveform at I301 Vertical Scan Abnormal Abnormal Normal No OK Replace I301 Check R307 short Still no vertical scan Check or replace CRT Yes Replace R307 ...

Page 23: ...k the waveform at the I501 pin 29 pin 32 pin 35 Check the waveform at the I901 pin 3 5 1 RGB Video AMP Abnormal Yes No Yes No Check B pin 10 6 Video signal present at the pin of the CRT R G B Cathode Defective cut off circuit DC restore Yes Check the waveform at pin 2 6 11 19 27 Check I501 Yes Yes Check I901 ...

Page 24: ...10807 DIODE BYM26C 2 3A 600V 4 D820 D826 6412000520 DIODE RL4A 3A 600V 5 D822 6412022207 DIODE SF20 02G 2A 200V 6 F801 6851504051 FUSE TIME LAG H BRK 19181 4A 7 I301 6442011210 IC TDA8351 N6 9P SIL PHILIPS 8 I401 6442025200 IC TDA4856 32P SDIP PHILIPS 9 I501 6442024210 IC M52743BSP 36P SDIP MITSUBISHI 10 I701 6448014500 IC NT68P61AU 42P PDIP OTP NOVAT 11 I703 6448007930 IC KS24C04 SAMSUNG 12 I802 ...

Page 25: ...R5Q27C 3PIN 26 R802 6201100052 THERMISTOR 10 OHM 8A P 7 5 TKS 27 R822 6221222852 MOF OHM 0 22 2W J HOR 28 T402 6119003205 COIL LINEAR DYNAMIC TLN 1032E 29 T40A 6139000300 XFRMER H CENT 5mH THC 1003 30 T801 T802 6138003100 LINE FILTER 31 T805 6131051820 XFRMER PWR TPW1069 ER42 15 LSE 32 X701 6449000700 CRYSTAL HC49 U 8MHZ 50PPM 7pF 33 I804 6442030500 IC MC33260 8P MOTOROLA 34 D807 6412000520 DIODE ...

Page 26: ... E A M P I 5 0 2 O S D I 9 0 1 L M 2 4 0 2 C R T A M P L I F I E R D C R E S T O R E B R I G H T N E S S C O N T R O L B L A N K I N G M U T I N G S O P T K I L L E R I 1 0 3 R E G U L A T O R Q 1 0 3 U P I 1 0 3 P W M C O N T R O L Q 1 0 4 H P L S D R I V E R T 1 0 1 F L Y B A C K T R A N S D Y N A M I C F O C U S A M P L I F I E R A B L R A S T E R C E N T E R H V D D C S D A D D C S C L S D A S...

Page 27: ...LITE ON TECHNOLOGY CORP 5 F No 16 Sec 4 Nanking E Road Taipei Taiwan Tel 886 2 25706999 Fax 886 2 25706888 URL www liteontc com tw Printed in Taiwan R ...

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