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Tatung Vibrant VM99S Service Manual
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Tatung Vibrant VM99S Service Manual

Tatung Vibrant VM99S Service Manual

19-inch color monitor
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Service Manual
19-inch Color Monitor
VM99S

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Summary of Contents for Tatung Vibrant VM99S

  • Page 1 Service Manual 19-inch Color Monitor VM99S...

  • Page 2: Table Of Contents

    Table of Contents 1. Precautions ......................... 2 2. Product Specifications ....................5 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.

  • Page 3: Precautions

    1 Precautions Follow these safety and servicing precautions to prevent damage and to protect against potential hazards such as electrical shock and X-rays. nonmetallic control knobs, insulating materials, 1-1 Safety Precautions cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacitor networks, mechanical insulators, etc.
  • Page 4 1-1-3 Product Safety Notices Many electrical and mechanical parts in this chassis have special safety-related characteristics which are often not evident from visual inspection, the protection afforded by them may not be obtained by replacing them with components rated for higher voltage, wattage, etc. Before replacing any of these components, consult the Recommended Spare Parts List given at the end of this manual.
  • Page 5 Plug monitor power cord to the Hi Pot tester terminals. Turn on tester and watch the indicator or beeper. If the indicator lamp lights, or beeper beeps, the test fails. 1-4 Ground Continuity Test 1. Test Equipment AC low ohm tester TOS-6100 or equivalent approved equipment. Note : The test equipment must be calibrated in regular period.

  • Page 6: Product Specifications

    Product Specifications 2-1 Specifications 19-inch, (18-inch visual image area) sloted mask, 90 degrees Picture Tube deflection, dot type black matrix, medium short persistence phosphor, dark tint, non-glare/ anti-static screen, 0.26 mm dot pitch Scanning Frequency V G A , S u p e r V G A , 1 0 2 4 x 7 6 8 @ 7 5 / 8 5 H z , 1 2 8 0 x 1 0 2 4 @ 8 5 H z Maximum Resolution 1600 dots (H) x 1200 lines (V) @75Hz refresh rate Display Area...
  • Page 7 2-2 Signal Cable Pin Connections Table 2-1. Signal Cable Pin Assignment S i g n a l S i g n a l R e d v i d e o + 5 V Green video Digital Ground Blue video Ground Ground Ground...
  • Page 8 2-3 Timing Chart This section describes the timings that the computer industry recognizes as standard for computer-generated video signals. Table 2-2. Timing Chart M o d e H . D o t s 1152 1024 1600 1280 1600 V . D o t s 1200 1024 1200...
  • Page 9 2-4 Power Saving Function Note: The monitor will be driven into “Power Saving” mode by the control signal from the display controller, as indicated by the amber-color power LED. Table 2-3. Power Saving Function State Power Consumption Light < 0 watts Green Active <3 watts...
  • Page 10 The monitor is designed with selected CRT and carefully routed wires around CRT, make sure exactly the same routing scheme is used when doing CRT replacement. The TCO 99 scheme is for international and environmental labelling of personal computers. The labelling scheme was developed as a joint effort by the TCO (The Swedish Confederation of Professional Employ ees), Naturskyddsforeningen (The Swedish Society for Nature Conservation) and NUTEK (The National Board for Industry and Technical Development in Sweden).

  • Page 11: Control Location And Functions

    3 Control Location and Functions (1) Function Key (2) Decrease Key (3) Increase Key (4) Select Key (5) Power LED (6) Power ON/OFF 3-1 Front Panel 3-2 Front Panel Keys Functions 1. Function Key: Display the main menu, and exit the adjustment screen and save adjustments. 2.

  • Page 12: Operation Theory

    Operation Theory This is a fully digital controlled multi-sync color monitor that is compliant with DDC1/2B Plug and Play VESA standard and offers the following main features. 4-1 Main Features 1. Simplified design with minimum components. 2. The NOVATEK NT68P65AU processor-- that has I C bus controlled geometric correction, contrast and brightness-- offers the functions for: (a) Contrast, (b) Brightness, (c) H-size, (d) H-position, (e) V-size, (f) V-position, (g) Pincushion, and (h) Trapezoid, (i) Pin Balance, (j) Parallelogram.
  • Page 13 4-3-1 Horizontal Section 1. The oscillator is driven by the currents in R472 and R468. The minimum oscillator frequency is determined by R472 and the maximum frequency is determined by R468. 2. Horizontal sync goes into pin 15 through R494. And horizontal flyback pulse goes into pin 1 through R479 and bypass filter C445 from Emitter of Q407 and C412, C433, C411, R419, C456, R421, D413 for AFC loop.
  • Page 14 4-3-7 Contrast Section 1. Contrast is controlled by I701 through I C bus to I501 (LM1267) directly. 2. Beam current is detected through T101 (FBT) pin 7, D106, C109, Q102, R108, R121, R122 to control I501 pin 22 voltage. When I501 pin 22 voltage drops below 5V, the ABL function will happen. 4-3-8 Dynamic focus circuitry The dynamic focus is applied to improve the corner focus performance, it includes horizontal and vertical dynamic focus.
  • Page 15 4-4-6 Synchronization 1. Normal Mode The sync pulse from FBT (31 kHz~95 kHz) via R812, R831, C815, R826, D824, C814 and R816 to pin 4 of I801 to keep I801 synchronized with horizontal sync input frequency. 2. Power Saving Modes: Off mode Because there is no pulse from FBT, so the free-run frequency is decided by R817 and C814 and the SMPS works at 22 kHz.
  • Page 16 1. The I502 NT6827-00002 is OSD IC. The OSD signals are worked by positive vertical pulse from I701 pin 32 that goes through R554 to I502 pin 10, and positive horizontal pulse from HFLB1 through R527 to I502 pin 5. CPU I701 pin 27, 28 (I C bus) transfers information to I502 pin 7, 8.

  • Page 17: Alignments And Adjustments

    5 Alignments and Adjustments This section of the service manual explains how to make permanent adjustments to the monitor settings. 5-1 General Adjustments 5-1-1 Adjustment Conditions a) Power Supply Apply AC 115 V or 220 V b) Warm-up Time The monitor must be powered on for 15 minutes before starting any alignment, but requires 30 minutes of warm-up time for convergence adjustment.
  • Page 18 5-2 Alignment Procedures 5-2-1 High Voltage Adjustment CONDITION Display image : Crosshatch pattern 5-2-2 Screen and White Balance Adjustment CONDITION Press buttons simultaneously when switching the power “On”. Display image : No video PROCEDURE Raster color setting Adjust HV icon to set high voltage = 26KV. Adjust G2 icon to set G2 at 600 ±...
  • Page 19 CONDITION Display image : full white pattern Set Brightness to cutoff and Contrast to maximum. Move cursor to choose ABL inside contrast icon. Adjust ABL to set Y=32±1FL Repeat all the procedures in 5-2-2 section until the best white balance is obtained. 5-2-3 Focus Adjustment CONDITION Display image : “e”...
  • Page 20 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. Figure 4-1. Convergence Magnets on the CRT FRONT 8 7 6 5 4 3 2 1) Setup Bolt...
  • Page 21 5-2-6 Degaussing Degaussing is required when poor color impurity appears on the screen. This monitor uses an automatic degaussing circuit that is activated when the power is on. The automatic degaussing will be fully functional again after the monitor has been in operation for 20 minutes. The degaussing effect is confined to the picture tube since the coils are mounted at the back of the tube.

  • Page 22: Troubleshooting

    6 Troubleshooting 6-1 No Raster No Raster Measure voltage of B+ at T402 pin 2 on PWB-MAIN Normal High (137 V, 91kHz) (175 V or more) Check voltage of Short Circuit cathode, heater, Grid Check I401 at load? 1, Grid 2, etc. Check Check DC B+ line, AC I/P on...
  • Page 23 6-2 OSD Abnormal OSD Abnormal Put on Check I502 I502 missing? Check R516, R526, R527 Replace them Check J516, Replace it R556 OK? Replace I502...
  • Page 24 6-3 Function Key Abnormal Function Key Abnormal Put on Check I701 and I701, I703 I703 missing? Power ON/OFF again and Replace X701 check X701, oscillator Check Replace I703 or do I703 EEPROM content ATE again Replace I701 and check Replace I701 uP OK? Check Check...
  • Page 25 6-4 No Vertical Scan (Raster is one horizontal line) No Vertical Scan Check I301 voltage of Check or replace pin 1 is 12V, pin I301. 2 is 37V and pin 4 is -14V? Check Abnormal pin 5 O/P waveform Replace I301 at I301 Normal Check...
  • Page 26 6-5 Out of Horizontal Synchronization Out of Horizontal Synchronization Horizontal Ckeck or replace sync present at the signal cable or pin 15 of I401 I701 Check Check or replace I401 pin 8 H output the signal cable frequency or I701 Check Q401, T401, Q402, R402, R403, C404, R404, D402, Q410...
  • Page 27 6-7 R.G.B. Video Amplifier Abnormal RGB Video AMP Abnormal Check Check or replace the waveform at I501 pin 18, 19 signal cable or I501 and 20 Check I901 pin 1, 3 and 2 voltage Replace I901 and wave form Video signal present at the pin of the CRT R.G.B.

  • Page 28: Recommended Spare Parts List

    7 Recommended Parts List Note:1. The components identified by “ “ mark are critical for X-ray safety. Replace these with exactly the same parts specified. Location Part Number Description C407 6325943252-03 P=22.5 PPS 4300P 1800V C808 6312633126 ALU uF 330 400V F 85C 25x40 D801 6417001000 TS4B05G-01...
  • Page 29 Location Part Number Description T101 6133093010 FBT TFB-9301 FM159R-B T402 6111444130 COIL CHOKE 4.4MH T801 6138002201 LINE FILTER TLF-1016A 16mHET28 T802 6131052500/510 XFRMER PWR TPW-1087 EE40 X701 6449006900 CRYSTAL 12MHz TOP8.000 30pF TOP 28 ** I901 6442032300 LM2465 9P I402 6442005900 LM324 14P 30 *** I801...

  • Page 30: Block Diagram

    B R G SCL1 Blanking LM1267 SDA1 HFLB1 Q541 VIDEO PREAMP Q542 CUT OFF HEATER R G B ADJUST Q901 Q902 G1 G2 Q931 P501 LM2465 Q932 I502 HFLB1 B-IN Q961 NT6827 Q962 VTTL Q903 R-IN Q933 Q963 G-IN P502 P505 C137 R132...