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Page 21

MD 1772LB (B1770NSL/T)

MEDION

6

Troubleshooting

6-1 No Raster

Measure

voltage of B+ at

T402 pin 3 on

PWB-MAIN

No Raster

Check voltage of

cathode, heater, Grid

1, Grid 2, etc.

Check I401

Normal

(68 V, 31.5 kHz)

High

(75 V or more)

Check

D801, D802, D803,

D804, T801, R804,

F801

Check I801,

Q803, R814,

R813, ZD807,

ZD801, R831,

R830, R818

Yes

Short Circuit

at load?

Check DC B+ line,

Q411, D817

Yes

0 V

Check AC I/P on

C808

No

No

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Summary of Contents for B1770NSL

Page 1: ...17 inch Color Monitor B1770NSL T MD1772LB Service Manual MEDION ...

Page 2: ...nslated or converted to any electronic or machine readable form without prior written permission of LiteOn Technology Corp B1770NSL NST 99 MD1772LB Service Manual Printed in Taiwan 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 Aug 11 2000 Original release ...

Page 3: ...Product Specifications 5 3 Control Location and Functions 10 4 Operation Theory 11 5 Alignments and Adjustments 16 6 Troubleshooting 21 7 Recommended Spare Parts List 27 8 Block Diagram 29 9 Exploded Diagrams Inserted 10 PCB Diagrams Inserted 11 Schematic Diagrams Inserted ...

Page 4: ...mum 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 compartme...

Page 5: ...ng 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 board...

Page 6: ...egular 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 the...

Page 7: ...chronization Frequencies Horizontal 30 to 70 kHz Vertical 50 to 160 Hz Signal Connectors 15 pin D shell connector Video Signals Analog 0 7 Vp p RGB positive Power Input 110 Watts maximum AC rated voltage 100VAC to 240VAC Misconvergence Center Area 0 3 mm Corner Area 0 4mm User Controls Power On Off Contrast Brightness Horizontal Size Horizontal Position Vertical Size Vertical Position Pincushion T...

Page 8: ...gnal Pin Signal 1 Red video 9 PC 2 Green video 10 Digital Ground 3 Blue video 11 Ground 4 Ground 12 SDA 5 NC 13 H Sync 6 Red ground 14 V Sync VCL 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 For PC99 this pin will provide 5V from PC side ...

Page 9: ... 6 4 6 35 5 33 5 172 4 923 4 409 4 053 3 657 4 028 3 589 3 725 C Sync us 3 81 3 81 2 116 3 2 2 03 1 556 1 616 2 092 1 138 1 813 1 219 1 185 0 972 1 016 D B P us 1 907 1 907 3 175 2 2 3 81 2 222 3 232 2 462 2 702 1 92 2 235 2 37 2 248 2 201 E Active us 25 42 25 42 21 164 20 20 32 17 778 16 162 15 75 14 22 13 65 13 11 848 11 96 10 836 F F P us 0 636 0 636 2 116 1 0 51 1 556 0 323 0 369 0 569 0 32 0 ...

Page 10: ...agnetic field requirements Also it is compliant with TCO 95 TCO 99 labelling scheme 2 6 1 TCO 92 Version Optional The emission from magnetic and electric field must comply with the limits specified by the Swedish Board for Measurement and Testing commonly known as MPR 1990 recommendations These limits are summarized in the Table 2 4 Table 2 4 TCO 92 Requirements O C T F L V O C T F L E d l e i F c...

Page 11: ...orinated solvents among other things The monitor is also recyclable 3 Energy Requirements The monitor also follows the energy requirements that after a certain period of inactivity the monitor shall reduce its power consumption to a lower level in one or more stages 4 Others The monitor meets the strict environmental demands for the reduction of electric and magnetic fields physical and visual erg...

Page 12: ...r by showing different color for each mode 6 Power ON OFF To turn the monitor ON and OFF 3 3 Adjustment Procedure 1 Press 6 key to turn on the monitor 2 At normal condition press 1 on the front panel to activate the on screen manager OSM menu 3 To select a user control press 2 or 3 key repeatedly until the control is highlighted 4 To adjust the value for a particular control press 4 then press the...

Page 13: ...ated if fH 29 kHz and fH 73 kHz 6 Full range AC input and simplified line filter design 4 2 Microcontrol Section 1 This monitor uses NOVATEK NT68P61AU CPU It contains a 6502 8 bit CPU core 256 bytes of RAM used as working RAM and stack area 24k bytes of OTP ROM 14 channel 8 bit PWM D A converter 2 channel A D converters for key detection saving I O pins internal H sync and V sync signals processor...

Page 14: ...om step up circuit output Step up circuit include Q405 R414 T403 D407 R411 R412 2 I401 TDA4856 pin 6 B DRV will drive the step up circuit to change H width 3 EW DRV pin11 provides a complete EW drive waveform including parabola corner and trapezoid correction and feed to BIN pin 5 of I401 to get a good control for pincushion trapezoid corner 4 The top and bottom corner correction can be adjusted s...

Page 15: ...DC 126 V 364 V for power conversion in T802 4 4 2 Line Filter It consists of C801 C802 C803 C816 C820 C823 C807 and T801 and meets EMI regulation 4 4 3 Power LED Status 1 The LED has 3 leads with common cathode to emit green and amber color light for different power saving states It is controlled by CPU 2 Normal Green light Amber LED is off because CPU pin 18 is high and pin 17 is low only green L...

Page 16: ...because the pin 6 duty cycle is limited too 4 4 9 High Voltage Generation with F B T 1 The H V generation circuit combines T402 F B T with I402 TL494 KA7500 PWM control circuit 2 When I402 Vcc pin12 reaches at 5V pin 5 6 gets a freerun sawtooth waveform about 25KHz and approximately 9 5Vp p when voltage at pin 15 is higher than pin 16 5V reference then release pin 3 to be controlled by pin 1 feedb...

Page 17: ...D signals are worked by positive vertical pulse from I701 pin 32 that goes through R521 to I502 pin 10 and positive horizontal pulse from HFLB1 through R513 to I502 pin 5 CPU I701 pin 27 28 I2 C bus transfers information to I502 pin 7 8 2 The OSD R G B signals and blanking signal are terminated at I502 pin 15 14 13 and 12 to I501 pin 2 3 4 and 1 then the OSD picture appears ...

Page 18: ...235 or equivalent 4 Minolta Color Analyzer II 5 Signal generator IBM PC with proper display cards or Chroma 2000 6 Screwdriver 5 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 war...

Page 19: ... brightness 0 9 1 2 FL 1 f Adjust Brightness to cut off CONDITION Display image 50 mm x 50 mm white block pattern PROCEDURE 2 65000 K color temperature setting 2 a Set Brightness to cutoff and Contrast to maximum 2 b Move cursor on OSD to choose color temperature icon 2 c Press 2 key to G gain then adjust G gain 68 value then adjust B R to y 329 5 x 313 5 2 d Check x 313 5 y 329 5 3 93000 K color ...

Page 20: ...e horizontal line clear 4 Repeat above procedures to get best focus 5 2 4 Dynamic focus Adjustments 1 Horizontal dynamic focus set Hf 300V in phase compare with Vcp signal 2 Vertical dynamic focus set Vf 160V in phase 5 2 5 Static Convergence Adjustments Static convergence involves alignment of the red blue and green lines in the center area of the display Note The monitor requires 30 minutes warm...

Page 21: ...ng between the 2 tabs to converge the horizontal red and blue lines at the center of the screen 5 Rotate the individual rings of 6 pole convergence magnets by changing the spacing between the 2 tabs to converge the vertical red blue and green lines 6 Rotate the pair of rings of 6 pole convergence magnets by maintaining spacing between the 2 tabs to converge the horizontal red blue and green lines ...

Page 22: ... affected area with a manual degaussing coil 5 2 7 Manual 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...

Page 23: ... on PWB MAIN No Raster Check voltage of cathode heater Grid 1 Grid 2 etc Check I401 Normal 68 V 31 5 kHz High 75 V or more Check D801 D802 D803 D804 T801 R804 F801 Check I801 Q803 R814 R813 ZD807 ZD801 R831 R830 R818 Yes Short Circuit at load Check DC B line Q411 D817 Yes 0 V Check AC I P on C808 No No ...

Page 24: ...age 22 MD 1772LB B1770NSL T MEDION 6 2 OSD Abnormal Put on I502 Replace them No Check I502 missing Check R530 R532 R531 OK OSD Abnormal Yes No No Replace it Yes Yes Check JP806 L504 L505 OK Replace I502 ...

Page 25: ...01 No Check I701 and I703 missing Power ON OFF again and check X701 oscillator OK Function Key Abnormal Yes No No Replace I703 or do ATE again Yes Replace I701 and check uP OK Yes Check I703 EEPROM content OK No Replace I804 Check pin 5 of I701 is 5V Replace I701 Yes Check R735 C710 Yes No ...

Page 26: ...ster is one horizontal line Ckeck or replace I301 Replace I301 Yes Check I301 voltage of pin 3 is 12V pin 7 is 48V Check pin 6 O P waveform at I301 No Vertical Scan Abnormal Normal No Check pin 1 2 9 of I301 waveform Still no vertical scan Check or replace CRT ...

Page 27: ...orizontal sync present at pin 15 of I401 Check I401 pin 8 H output frequency Out of Horizontal Synchronization No Yes No Check Q401 T401 Q402 R4A6 D402 R403 D402 6 6 Out of Vertical Synchronization Ckeck signal cable vertical sync input I701 Yes Vertical sync present at pin 14 of I401 Check I401 pin 24 ramp frequency Out of Vertical Synchronization No Check C441 ...

Page 28: ...replace the signal cable or I501 Yes Check waveform at I501 pin 16 19 and 22 Check Q963 Q903 Q933 collector voltage and wave form RGB Video AMP Abnormal Yes No Yes No Check Q964 Q904 Q934 Video signal present at the pin of the CRT R G B Cathode Defective cut off circuit DC restore ...

Page 29: ...4 D814 6412017900 DIODE RL3 3 5A 350V SANKEN 5 D815 6412004117 DIODE UF2004M T52 2A 400V 50nS 6 D429 D407 6412020203 DIODE HER305 BXF 3A 400V 7 F801 6851004050 FUSE TIME LAG 5ST4 4A 250V 8 I301 6442012300 IC TDA4866 9P PHILIPS 9 I401 6442025200 IC TDA4856 32P SDIP PHILIPS 10 I501 6442021500 IC TDA4886 24P SDIP PHILIPS 11 I701 6448014500 IC NT68P61AU 40P PDIP OTP NOVAT 12 I703 6448007930 IC 24C04 S...

Page 30: ...M 0 27 1W J HOR 24 T401 6135000801 XFRMR HOR DRIVE THD 1008A EI19 25 T402 6133070120 FBT TFB 7012 FEA867 SAMPO 26 T403 6111155174 COIL CHOKE 150 uH 27 T801 6138001601 LINE FILTER TLF 1016A 16mHET28 28 T802 6131060820 XFRMER PWR TPW 1070 EI40 29 X701 6449000719 CRYSTAL 8MHz TOP8 000 30pF TOP 30 D813 D817 6412000520 DIODE RL4A 3A 600V 50nS SANKEN ...

Page 31: ...2 Q811 7V SWITCH 12V SWITCH Q813 LINE FILTER H DRIVER Q402 D403 C406 B DRIVER Q405 T403 LINEARITY CONTROL L404 L405 BRIGHTNESS CONTROL SPOT KILLER ABL C O N T R O L CKT Q418 Q419 G2 CONTROL VR Q413 CANCELING C K T I402 PWM CONTROL TL494 KA7500 T402 FBT Q411 FBT DRIVER H CENTER Q406 VR403 XRP CKT B R G GND GND GND P901 R G B HEATER P903 G1 6 3V 12V 80V GND 130V GND G1 G2 FOCUS 1 FOCUS 2 4V B R G 8V...

Page 32: ...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 MEDION ...

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