NEC AS120-1 Service Manual

Chassis no.: ca-134 factory model: as120j

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COLOR MONITOR

SERVICE MANUAL

CHASSIS NO. : CA-134
FACTORY MODEL: AS120J
MODEL: AS120-1, AS120-BK-1
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

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Summary of Contents for NEC AS120-1

  • Page 1: Color Monitor

    COLOR MONITOR SERVICE MANUAL CHASSIS NO. : CA-134 FACTORY MODEL: AS120J MODEL: AS120-1, AS120-BK-1 CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
  • Page 2: Table Of Contents

    CONTENTS SPECIFICATIONS ........... 2 ADJUSTMENT ............10 SAFETY PRECAUTIONS ........3 TROUBLESHOOTING GUIDE ......12 TIMING CHART ............4 EXPLODED VIEW..........18 OPERATING INSTRUCTIONS ........ 5 REPLACEMENT PARTS LIST ......20 WIRING DIAGRAM ..........6 PIN CONFIGURATION .......... 26 BLOCK DIAGRAM ........... 7 SCHEMATIC DIAGRAM .........
  • Page 3: Safety Precautions

    SAFETY PRECAUTIONS SAFETY-RELATED COMPONENT WARNING! X-RADIATION There are special components used in this color monitor The only potential source of X-radiation is the picture tube. which are important for safety. These parts are marked However, when the high voltage circuit is operating on the schematic diagram and the replacement properly there is no possibility of an X-radiation problem.
  • Page 4: Timing Chart

    TIMING CHART VIDEO SYNC MODE MARK MODE 1 MODE 2 MODE 3 MODE 4 MODE 5 MODE 6 MODE 7 MODE 8 Sync Polarity — — — Frequency 31.469 31.469 43.269 60.023 68.677 79.976 91.146 93.750 µs Total Period 31.778 31.778 23.111 16.660...
  • Page 5: Wiring Diagram

    WIRING DIAGRAM P503 P401 P451 P402 P452 P453 P801 P901 P701 Socket Signal Cable P302 P301 P303 - 6 -...
  • Page 6: Block Diagram

    BLOCK DIAGRAM - 7 -...
  • Page 7: Description Of Block Diagram

    DESCRIPTION OF BLOCK DIAGRAM 1. Line Filter & Associated Circuit. 5. X-ray Protection. This is used for suppressing noise of power input line This circuit detects the rectified DC voltage comes flowing into the monitor and/or some noise generated from the FBT pin 4. If the high voltage of the FBT in this monitor flowing out through the power input reaches up to about 30kV (abnormal state), H.V control (IC802) detects.
  • Page 8 12. High Voltage Output & FBT (Flyback Transformer). 18. Static Convergence Control Circuit. The high voltage output circuit is used for generating This circuit corrects the convergence of the screen by pulse wave to the primary coil of the FBT (Flyback supplying the convergence signal to the H/V-STC coil Transformer (T701)).
  • Page 9: Adjustment

    ADJUSTMENT GENERAL INFORMATION 3) EEPROM → ALL CLEAR → Y(Yes) command. All adjustment are thoroughly checked and corrected when the monitor leaves the factory, but sometimes <Caution> Do not run this procedure unless the several adjustments may be required. EEPROM is changed. All data in EEPROM (mode Adjustment should be following procedure and after data and color data) will be erased.
  • Page 10 11) Display color 15,0 Full White(70x70mm) at mode 7. 6. Adjustment for Focus. 12) DRIVE ADJ command. 1) Display H character in full screen at Mode 7. 13) Set B-DRIVE to 90(5A(h)) at DRIVE of the 2) Adjust two Focus control on the FBT that focus alignment program.
  • Page 11: Troubleshooting Guide

    TROUBLESHOOTING GUIDE 1. NO POWER NO POWER (POWER INDICATOR OFF) CHECK TROUBLE IN FUSE OK? FUSE (F901) (F901) CHECK TROUBLE IN D901 BRIDGE DIODE BRIDGE DIODE? (D901) CHECK C905(+) VOLTAGE TROUBLE IN 145VDC at 110V input 310VDC at 220V input IC901 CHECK TROUBLE IN...
  • Page 12 2. NO CHARACTER NO CHARACTER TROUBLE IN CHECK P301, SIGNAL CABLE, IC302 PIN 5, 6, 7 ? PC SIGNAL CHECK TROUBLE IN IC302 PIN 19, 20, 21 IC302, P302 PIN 10 (5V) ? CHECK IC303 PIN 1, 3, 5 TROUBLE IN PIN10 (12V), IC303 PIN 6 (80V) ?
  • Page 13 3. NO RASTER NO VIDEO (POWER INDICATOR GREEN or AMBER) CHECK AMBER POWER INDICATOR TROUBLE IN GREEN or AMBER ? P302 SIGNAL CABLE GREEN CHECK ROTATE SCREEN SCREEN CONTROL CONTROL KNOB TO KNOB OF FBT CLOCKWISE or COUNTER CLOCKWIES CHECK VOLTAGE AT D924/D926 CATHODE (190V) TROUBLE IN PRIMARY...
  • Page 14 4. NO VERTICAL DEFLECTION NO V-DEFLECTION (ONE HORIZONTAL LINE) CHECK TROUBLE IN IC601 Pin 3 T901 15V LINE (15V) ? CHECK TROUBLE IN IC601 PIN 7 T701 47V LINE (47V)? CHECK TROUBLE IN IC801 PIN 12 IC801 (SAWTOOTH WAVE)? TROUBLE IN IC601, V-CIRCUIT - 15 -...
  • Page 15 5. TROUBLE IN DPM STAND-BY/SUSPEND/ DPMS OFF MODE FAILURE CHECK CHECK PC, IC401 (MICOM) INPUT H/V SYNC SIGNAL (PC IS NOT GOING INTO PIN 40, 41 (H/V INPUT) DPM MODE) SIGNAL? NO H/V SYNC SIGNAL CHECK TROUBLE IN IC401 PIN 9, 8 X401, IC401 WAVEFORM? CHECK...
  • Page 16: No Degaussing

    6. NO DEGAUSSING NO DEGAUSSING CHECK TROUBLE IN IC401 PIN 6 IC401 (MICOM) (5V)? CHECK TROUBLE IN Q920 COLLECTOR D925 VOLTAGE (0.5V)? CHECK TROUBLE IN P901? P901 CHECK TROUBLE IN RL901? RL901 TROUBLE IN TH901, DEGAUSSING COIL - 17 -...
  • Page 17: Front View

    OPERATING INSTRUCTIONS FRONT VIEW REAR VIEW D-Sub Signal Connector Front Control Panel Power ON/OFF Button AC Power Socket Power Indicator Front Control Panel 1. Power ON/OFF Button 3. + / – Adjust Buttons This button is used to turn the monitor ON and OFF. Use these buttons for adjusting the level of the selected item.
  • Page 18 - 18 -...
  • Page 19: Exploded View

    EXPLODED VIEW PARTS LIST Ref. No. Part No. Description 3091TKD003G CABINET ASSEMBLY, CN291E NEC D003 AF345 - White 3091TKD003H CABINET ASSEMBLY, CN291E NEC D003 AS120 - Black 6318G21001A CDT(CIRC), M51QBN291X115(E-TCO) SAMSUNG 107KHZ 29.1MM FST 3809TKD001K BACK COVER ASSY, CN291E(NEC) D001 8A793 - White 3809TKD001M BACK COVER ASSEMBLY, CN291E D001E E-CORE AS120 - Black 3043TKK002L...
  • Page 20: Replacement Parts List

    REPLACEMENT PARTS LIST CAUTION: BEFORE REPLACING ANY OF THESE COMPONENTS, READ CAREFULLY THE SAFETY PRECAUTIONS IN THIS MANUAL. * NOTE SAFETY Mark AL ALTERNATIVE PARTS DATE: 2003. 8. 25. DATE: 2003. 8. 25. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC.
  • Page 21 DATE: 2003. 8. 25. DATE: 2003. 8. 25. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION C820 0CN1040K949 0.1UF 50V Z F TR C932 0CC47001505 47PF 1KV K SL TR C821 0CN1040K949 0.1M 50V Z F TA52...
  • Page 22 DATE: 2003. 8. 25. DATE: 2003. 8. 25. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION D812 0DS141489AB 1N4148 TP GRANDE DO-34 500MW IC601 0IPRPPH018A “TDA4867J PHILIPS 9PIN,ST DIP” D831 0DR260400AA S2L60-4004P15 BK SHINDENGEN IC702...
  • Page 23 DATE: 2003. 8. 25. DATE: 2003. 8. 25. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION Q701 0TR320509AB KTC3205-Y(KTC2236A) TP KEC T R315 0RD1000Q609 100 1/4W(3 5% TA52 Q704 0TFFN10003C INFINEON SPA07N60C3(E8153) S R319 0RD8201Q609...
  • Page 24 DATE: 2003. 8. 25. DATE: 2003. 8. 25. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R462 0RD0102A609 10 OHM 1/2 W (7.0) 5% TA52 R764 0RD0472Q609 47 1/4W(3 5% TA52 R463 0RD6801Q609 6.80K 1/4W(3 5% TA52...
  • Page 25 DATE: 2003. 8. 25. DATE: 2003. 8. 25. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R891 0RN2701F409 2.7K OHM 1/6 W 1.00% TA52 SG301 6918TAT005E MTAS-201M GIGA AXIAL TAPING R892 0RN6800F409 680 1/6W 1% TA52...
  • Page 26: Pin Configuration

    PIN CONFIGURATION M24C08 Serial I C BUS EEPROM SYMBOL PSDIP8 (BN) DESCRIPTION 0.25mm Frame Chip Enable Input E0-E2 Serial Data Address Input/Output Serial Clock Write Control SO8 (MN) 150mil Width Supply Voltage Logic Dirgram TSSOP8 (DW) Ground 169mil Width M62501P /FP Teerminal Number and The facillty PIN CONFIGURATION(TOP VIEW) PIN NO.
  • Page 27 TDA4867J PHILIPS 32P, SDIP SYMBOL DESCRIPTION non-inverted input inverted input supply voltage OUTB output B OUTB ground TDA4867J OUTA output A OUTA flyback supply voltage V FB GUARD guard output GUARD FEEDB feedback inprt FEEDB Pin Configuration GUARO output/ power save mode GUARD FLYBACK CIRCUIT...
  • Page 28 TDA4841PS PHLIPS 32P HFLB FOCUS XRAY HSMOD HPLL2 BSENS HCAP HREF BDRV HBUF PGND HPLL1 HDRV SGND TDA4841PS XSEL VCAP VREF EWDRV VAGC VOUT2 VSMOD VOUT1 ASCOR VSYNC HSYBC CLBL HUNLOCK Pin Configuration EHT compensaton Block Diagram via vertical size EHT compensation via horizontal size 1.2V...
  • Page 29: Schematic Diagram

    SCHEMATIC DIAGRAM NOTICE Since this is a basic schematic diagram. The value of components and some partial connection are sucject to be changed for improvement without notice. - 29 - - 30 -...
  • Page 30: Printed Circuit Board

    PRINTED CIRCUIT BOARD 2. CONTROL BOARD (Solder Side) 1. CONTROL BOARD (Component Side) 3. MAIN BOARD (Component Side) 4. MAIN BOARD (Solder Side) - 31 - - 32 -...
  • Page 31 Aug. 2003 P/NO : 3828TSO036C Printed in Korea...

This manual is also suitable for:

As120-bk-1

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