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Tatung Vibrant VM78F, Service Manual

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Tatung Vibrant VM78F Service Manual Download Page 7

Product Specifications

Page 6

 VM78F

2-2 Signal Cable Pin Connections

Table 2-2. Signal Cable Pin Assignment

Pin

Signal

Pin

Signal

1

Red video

9 * *

+ 5 V

2

Green video

1 0

Digital Ground

3

Blue video

11

Ground

4

Ground

1 2

SDA

5 *

NC

1 3

H-Sync

6

Red ground

1 4

V-Sync/VCL

7

Green ground

1 5

SCL

8

Blue ground

Note *

This pin is used for selftest detection.  Connect this pin to ground at the PC end.

        **

For PC 99: This pin will p5V from PC side.

Summary of Contents for Vibrant VM78F

Page 1: ...17 inch Color Monitor VM78F Service Manual ...

Page 2: ...2 2 Product Specifications 5 3 Operation Theory 10 4 Alignments and Adjustments 15 5 Troubleshooting 19 6 Recommended Spare Parts List 26 7 Block Diagram 28 8 Exploded Diagrams Inserted 9 PCB Diagrams Inserted 10 Schematic Diagrams Inserted ...

Page 3: ...r 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 compartment covers or sh...

Page 4: ...stalling 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 5 Keep ...

Page 5: ... 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 Tester has a d...

Page 6: ...ncies Horizontal 30 to 86 kHz Vertical 50 to 120 Hz Signal Connectors 15 pin D shell connector Video Signals Analog 0 7 Vp p RGB positive Power Input 75 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 Trapezoid Rotation Co...

Page 7: ... 1 Red video 9 5V 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 PC 99 This pin will provide 5V from PC side ...

Page 8: ... 14 56 12 504 11 636 B Blking us 6 356 6 356 6 4 5 33 5 172 4 923 4 409 3 657 3 589 3 725 3 022 3 017 C Sync us 3 81 3 81 3 2 1 556 1 616 2 092 1 138 1 219 0 972 1 016 1 067 1 077 D B P us 1 907 1 907 2 2 2 22 3 232 2 462 2 702 2 235 2 248 2 201 1 837 1 508 E Active us 25 42 25 42 20 17 78 16 162 15 75 14 22 13 11 96 10 836 9 481 8 62 F F P us 0 636 0 636 1 1 556 0 323 0 369 0 569 0 203 0 374 0 50...

Page 9: ...d 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 5 TCO 95 Emission Requirements VLF TCO ELF TCO Magnetic Field 25 nT 200 nT Electric Field 1 V m 10 V m Frequency Range 2 400 kHz 5 2000 Hz Value RMS RMS Distance 30 cm 30 cm Electrostatic Potential 50...

Page 10: ...nated and chlorinated flame retardants CFCs freons and chlorinated 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 reducti...

Page 11: ...ction and l Full horizontal and vertical auto sync capability 5 Software controlled auto shut off function activated if fH 29 kHz and fH 86 kHz 6 Full range AC input and simplified line filter design 3 2 Microcontrol Section 1 This monitor uses MYSON MTV212 M A 32 CPU It contains a 8051 8 bit CPU core 256 bytes of RAM used as working RAM and stack area 32k bytes of OTP ROM 13 channel 8 bit PWM D A...

Page 12: ...863 2 The TDA4863 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 This IC is powered by two sets of positive voltage and one set of negative voltage 11 7V at pin 1 11V at pin 4 40V at pin 2 3 3 4 E W Trapezoid and H Width Controls 1 The horizontal O P stage uses diode modulator D419 D433 C411 C412...

Page 13: ... R4F9 Q428 R4G0 Q431 R4G1 then through R302 to I401 pin 21 for V size compensation 3 3 9 Dynamic focus circuitry The dynamic focus is applied to improve the corner focus performance it includes horizontal and vertical dynamic focus 1 Horizontal dynamic comes from C413 and is amplified through T403 L405 H DY L402 C411 R417 C450 C448 R435 and feed to FBT dynamic focus pin T401 pin 12 2 Vertical dyna...

Page 14: ...orizontal sync input frequency 2 Power Saving Modes Standby Suspend Because there is no pulse from FBT so the free run frequency SMPS works at 20 kHz by I801 itself 3 Override The horizontal free run frequency is about 63 2 kHz under override condition SMPS is synchronized to this frequency 3 4 7 O V P If the auxiliary voltage is higher than 25 volts makes pin 3 of I801 is limited to have the OVP ...

Page 15: ...ted by I503 LM2479 pin 8 7 6 which comes from I501 pin 16 15 14 to adjust cut iff voltage level by I2 C bus 5 Under override condition NO SIGNAL will show up on the screen 3 6 OSD On Screen Display Circuit 1 The I504 MTV021 08 is OSD IC The OSD signals are worked by positive vertical pulse from I701 pin 34 that goes through R720 to I502 pin 10 and positive horizontal pulse from T402 pin 5 goes thr...

Page 16: ...50C or equivalent 2 30 kV high voltage probe HP34111A 3 Oscilloscope TEK2235 or equivalent 4 Minolta Color Analyzer II 5 Signal generator IBM PC with proper display cards or Chroma 2000 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 fol...

Page 17: ...ff to min 1 c Adjust Gcutoff toabout 0 45FL 1 d Adjust Bcutoff to get y 283 5 Rcutoff to get x 298 5 and Y 0 65 0 05 FL 1 e Adjust Brightnesscutoff to raster0 01 0 02 FL CONDITION Display image 50 mm x 50 mm white block pattern PROCEDURE 2 65000 Kcolortemperature setting 2 a SetBrightness to cutoffand Contrastto maximum 2 b Move cursoron OSD to choose color temperature icon 2 c With green block pa...

Page 18: ... static focus VR to make horizontal line clear 4 Repeat above procedures to get best focus 4 2 4 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 of warm up time for convergence adjustment CONDITION Display image Crosshatch pattern Warm up Time 30 minutes PROCEDURE 1 Set Brigh...

Page 19: ...ually reduced by moving the coil slowly away from the monitor The degaussing coil must never be shut off or disconnected while near the monitor as this would introduce a strong field instead of canceling the effect of the stray fields 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 t...

Page 20: ...ck I801 R807 R808 Q801 Q802 ZD802 VR801 Check D801 D802 D803 D804 T801 R804 F801 Yes No Normal 56 V 31 5 kHz Short Circuit at load Measure voltage of B at T402 pin 2 on PWB MAIN No Raster 0 V High 75 V or more Check DC B line Q451 Q402 T402 Yes Check voltage of C808 No 5 Troubleshooting 5 1 No Raster ...

Page 21: ...M78F 5 2 OSD Abnormal Put on I502 Replace them No Check I502 pin 9 4 is 5V and pin 5 10 7 8 missing Check R517 L514 R527 R523 R524 OK OSD Abnormal Yes No No Replace it Yes Yes Check P502 OK Replace I502 ...

Page 22: ...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 I705 Q701 Q702 R728 Check pin 8 of I701 is 5V Replace I701 Yes Check ZD701 R735 Yes No ...

Page 23: ...ace I301 Check R312 R307 R306 R313 R308 R315 R316 Yes Check I301 voltage of pin 1 is 12V pin 4 is 11V pin 2 is 40V Check pin 5 O P waveform at I301 No Vertical Scan No Yes No Check pin 6 7 of I301 waveform Still no vertical scan Check or replace CRT Replace I401 No ...

Page 24: ...Check I401 pin 8 H output frequency pin 29 waveform Out of Horizontal Synchronization No Yes No Check Q401 T401 Q402 R424 D401 Check signal cable V sync pin 42 of I701 Check or replace C303 I401 Yes Verizontal sync present at pin 14 of I401 Check I401 pin 24 waveform Out of Verizontal Synchronization No Yes No Check I401 pin 12 pin 13 5 6 Out of Vertical Synchronization ...

Page 25: ...1 pin 5 6 and 7 Check I502 pin 1 2 and 3 collector voltage normally about 70V waveform RGB Video AMP Abnormal Yes No Yes No Replace I502 Video signal present at the pin of the CRT R G B Cathode Defective cut off circuit DC restore I504 Yes Check waveform at I501 pin 18 pin 19 and pin 20 No Replace I501 ...

Page 26: ... 1A 600V 50 nS 8 F801 6851504053 FUSE TIME LAG H BRK 4A 250V 9 I301 6442026400 IC TDA4863J 7P PHILIPS 10 I401 6442030000 IC TDA4841 32P SDIP PHILIPS 11 I501 6442031500 IC LM1267 24P SDIP NS 12 I502 6442029700 IC LM2469 9P NS 13 I503 6442029900 IC LM2479 8P NS 14 I701 6448014500 IC MTV212 M A S32 40P PDIP MYSON 15 I703 6448015720 IC MTV24C08 MYSON 16 I705 6442000875 IC KIA78L05 SAMSUNG 17 I801 6442...

Page 27: ...ISTOR OHM DGC2R08M 28 R804 6201100012 THERMISTOR 10 OHM 3A P 5 UEI 29 R802 6221127852 MOF OHM 0 27 1W J HOR 30 R4E3 6221227852 MOF OHM 0 27 2W J HOR 31 T401 6135000801 XFRMER HOR DRIVE THD 1008A EI19 32 T402 6133086010 FBT TFB 8601 SAMPO 33 T403 6136001700 XFRMER DYNAMIC TDF 1017 EI22 LSE 34 T801 6138001603 LINE FILTER TLF 1016C 16mH LSE 35 T802 6131053000 XFRMER PWR TPW 1088 EERL35 LSE 36 X701 64...

Page 28: ...GHTNESS CONTROL SPOT KILLER H DRIVER BRIGHTNESS H OUT DIODE MODULATE FBT STEP UP CKT D Y XRP 80V 150V 560V 6 6KV 115V V V H H P502 P501 25 6KV VTTL GND VIDEO 5 V O R 5V Q811 TDA4863J 5V H V SG SDA SCL O R SDA 1 V H Q813 dynamic foucus G1 ABL CLBL HFLB SDA1 SCL1 SW5 V OSD MTV021 5V OSD BLK R G B R G B HFLB ABL R G B 6 3V Vertical Focus 6 3V 11 7V I705 78L05 Q701 Q702 5V SW CKT R DAC G DAC B DAC GND...

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