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Mitsubishi Electric 1786FD2 Service Manual

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Diamond View Monitor
1786FD2
Service Guide
July 2002
Distributed by
Mitsubishi Electric Australia Pty.Ltd.
A.B.N. 58 001 215 792
348 Victoria Road
RYDALMERE NSW 2116
Australia
Telephone 1300 605 808

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Summary of Contents for Mitsubishi Electric 1786FD2

  • Page 1 Diamond View Monitor 1786FD2 Service Guide July 2002 Distributed by Mitsubishi Electric Australia Pty.Ltd. A.B.N. 58 001 215 792 348 Victoria Road RYDALMERE NSW 2116 Australia Telephone 1300 605 808...
  • Page 2 Copyright Copyright ã 1996 by the Company. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written permission of the Company.
  • Page 3 Diamond View 1786FD2 Manual Contents Section Engineering Specifications Circuit Operation Theory Alignment procedure Trouble Shooting Schematic Diagrams...

  • Page 4: Table Of Contents

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Table of Contents 0. INTRODUCTION :............................3 1. ELECTRICAL CHARACTERISTICS......................3 1.1 POWER SUPPLY ............................3 1.2SIGNALINTERFACE ..........................3 1.3 SCAN RANGE............................3 VIDEO PERFORMANCE ........................4 1.5 TIMINGS ..............................4 2.ENVIRONMENT & RELIABILITY ......................5 3.CRT CHARACTERISTICS.........................6 4.FRONT OF SCREEN ...........................6 4.1 GEOMETRY............................6...
  • Page 5 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Table of Contents TABLE 2 - CRT BLEMISH & SCRATCH SPEC ..................25 TABLE 3 - OSD MENU..........................25 TABLE 4 - GEOMETRY FIG........................26 TABLE 5 - TCO 99 SPEC ..........................40...

  • Page 6: Introduction

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 0. Introduction : The subject model is designed for a value line 17” color monitor. It has the following figures : 0.25mm dot pitch CRT, 135MHz video bandwidth, 1280x1024 max. resolution. Low radiation TCO99 standard.

  • Page 7: Video Performance

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Condition Spec Remark VIDEO PERFORMANCE √ Dot Rate 135 MHz √ Max. Resolution 1280 x 1024 √ Rise time/Fall time 5.5 ns √ Video Ringing 5% max √ 5% max √ Bandwidth -3db 135 MHz √...

  • Page 8: Environment & Reliability

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 2.Environment & Reliability Condition Spec Remark √ Operation Temp./Humidity +5 ~ +40 ¢ J / 20~90% R.H. Non-condensing √ -20~ +60 ¢ J / 10~90% R.H. Non- Operation Temp./Humi. Non-condensing √ Altitude...

  • Page 9: Crt Characteristics

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 3.CRT Characteristics Spec Remark √ CRT Vender SAMSUNG √ Technology √ Coating Anti-reflection/Anti-static √ Dot pitch 0.25mm √ Phosphor √ Light transmittance 52.6% √ Viewable size 16” √ Deflection angle 90 deg √...

  • Page 10: Sharpness Crispness

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Remark 4.2SHARPNESS CRISPNESS √ Focus “e,w,m” at cut-off and Reverse character(white The distance of watch is 1024 x 768 resolution background and black characters) 30cm from eyes to screen √ Mis-convergence Center < 0.15 mm A <...

  • Page 11: User Controls

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 5. User Controls Function Spec Remark 5.1 BASIC √ Power Switch √ Contrast √ Brightness √ H Size √ H Position √ V Size √ V Position √ Barrel/Pincushion √ Parallelogram √...

  • Page 12: Mechanical Characteristics

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 6. Mechanical Characteristics Spec Remark 6.1 DIMENSION √ Bezel opening 324.8 x 243.5 mm √ Monitor w/o Stand L x W x H mm 417.5x406x371 mm √ Monitor w Stand L x W x H mm 417.5x406x422 mm...

  • Page 13: Pallet & Shipment

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 7. Pallet & Shipment 7.1 Dimension Transport Type Pallet A Pallet B Pallet C Shipping Pallet Length 1150 Dimension(mm) Width 1080 Height Air Transport Pallet Length 1150 1725 Dimension(mm) Width 1080 1080 Height 7.2 Shipping Container...

  • Page 14: Air Transport Container

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 7.3 Air Transport Container Container Type Quantity of products Quantity of Products Quantity of pallet (sets) (sets) (sets) (Every container) (Every Pallet) (Every Container) Container Pallet A: Pallet A: 2 3048 * 2286 * 2438...
  • Page 15 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification √ CB (Nordics) √ TUV/GS EN60950 √ CCEE (China) √ EIAJ/JEIDA (Japan) √ NOM (Mexico) √ IAA (Korea) √ CE Mark 89/336/EEC √ FCC (USA) Class B √ EN55022 Class B √...

  • Page 16: Appendix Table

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 9. Appendix Table Table 1 - DDC Table Address Data Description Header ID Manufacturer Name = API ID Product Code = G781 (Vender Assigned code) ID Serial Number 32 bits serial no.
  • Page 17 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification White x bit9-2 White y bit9-2...
  • Page 18 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Address Data Description Established Timing I Established Timing II Established Timing III Standard Timing Identification #1 800x600 @85Hz #2 1024x768 @85Hz Detailed Timing Description # 1 Pixel clock = 94.5Mhz Hor. Display = 1024 pixels Hor.
  • Page 19 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification...
  • Page 20 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Address Data Description Monitor name=Acer G781 SN 00001...
  • Page 21 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Address Data Description Range limit V.Freq range 50-120Hz H.Freq range 30-86KHz Max pix clock 150 MHz Extension Flag Check sum...
  • Page 22 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Samsung TCO99 Tube (gamma*100) – 100 DPMS Red Green Bits Rx1Rx0Ry1Ry0Gx1Gx0Gy1Gy0 Blue White Bits Bx1Bx0By1By0Wx1Wx0Wy1Wy0 Red x bit9-2 Red y bit9-2 Green x bit9-2 Green y bits9-2 Blue x bit9-2 Blue y bit9-2...
  • Page 23 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Philips MPRII Tube (gamma*100) – 100 DPMS Red Green Bits Rx1Rx0Ry1Ry0Gx1Gx0Gy1Gy0 Blue White Bits Bx1Bx0By1By0Wx1Wx0Wy1Wy0 Red x bit9-2 Red y bit9-2 Green x bit9-2 Green y bits9-2 Blue x bit9-2 Blue y bit9-2...
  • Page 24 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification ChungHwa MPRII Tube (gamma*100) – 100 DPMS Red Green Bits Rx1Rx0Ry1Ry0Gx1Gx0Gy1Gy0 Blue White Bits Bx1Bx0By1By0Wx1Wx0Wy1Wy0 Red x bit9-2 Red y bit9-2 Green x bit9-2 Green y bits9-2 Blue x bit9-2 Blue y bit9-2...
  • Page 25 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Description Analog / Digital Input : Defines usage of the rest if the byte as "analog input" or digital input". Analog=0, Digital=1 . If input is described as analog, the following definitions apply to bits 6-0.
  • Page 26 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Note 2 Bit 7 Stand-by Bit 6 Suspend Bit 5 Active off Display Type 0,0 - Monochrome/gray scale display 0,1 - RGB color display 1,0 - Non-RGB multicolor display (example:RGY) 1,1 - Undefined.
  • Page 27 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Note 4 Byte 1 Established Timings 1 Source 640*400 @ 70Hz (720x400) (VGA, IBM) 720*400 @ 88Hz (XGA2, IBM) 640*480 @ 60Hz (VGA, IBM) 640*480 @ 67Hz (Mac II, Apple) 640*480 @ 72Hz...

  • Page 28: Table 2 - Crt Blemish & Scratch Spec

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Table 2 - CRT Blemish & Scratch Spec The following criteria is applied to high-contrast blemishes. Allowable No. of Blemishes Allowable Minimum Blemishes Zone Zone Total Separation (Zones A & B )

  • Page 29: Table 4 - Geometry Fig

    MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Table 4 - Geometry Fig. Fig.1 Linearity Measurements ~ X18 Xmax - Xmin ------------------- x 100% <= 5% Xmax + Xmin Ymax - Ymin ------------------- x 100% < =5% Ymax + Ymin...
  • Page 30 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Fig.2 General Pincushion Measurements Bmm b1 A, B represented as display area width and height Top/Bottom Pincushion = (a1 or a2) Side Pincushion = (b1 or b2) Substituted A by (PS + QR)/2...
  • Page 31 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Fig.3 Trapezoid Measurements * Each of the 4 corners of picture shall fall within the relevant area (F) illustrated up (hatched) * ABCD is the picture outlines.
  • Page 32 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Fig.4 Picture Distortion & Phase Measurements orthogoal Tilt Total Peak − − − ≤ ≤ ≤...
  • Page 33 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Fig.5 TCO 99 Pincushion Measurements ∆ y1 ∆x1 ∆ x2 ∆ y2 [AC+EG]/2, [AG+CE]/2 represented as display area width and height Top/Bottom Pincushion = ∆y1 or ∆y2 Side Pincushion = ∆x1 or ∆x2...
  • Page 34 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Fig.6 TCO 99 Barreling Measurements ∆ y1 ∆x1 ∆ x2 ∆ y2 [AC+EG]/2, [AG+CE]/2 represented as display area width and height Top/Bottom Pincushion = ∆y1 or ∆y2 Side Pincushion = ∆x1 or ∆x2 Linearity (TCO99) = ∆x1/x or ∆y1/y...
  • Page 35 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Pooltag Disabled EDID Test Log file opened 08/09/00 - 08:34:38 EDID Dump follows: ******************* CheckSum validation ******************* PASS - Checksum valid - Proceeding with test *********************************************************** 128 bytes EDID Data (Hex): 0: 00 FF FF FF FF FF FF 00 06 09...
  • Page 36 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification ID Manufacturer Name: ID Product Code: **************** Product Code Validation **************** PASS - Product code valid. ********************************************************* ID Serial Number: 000F0000 Week of Manufacture: Year of Manufacture: 2000 <-x-Vendor/Product Identification-x-> <---EDID Structure Version/Revision--->...
  • Page 37 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification ************************ DPMS Support Check ******************** **** PASS - DPMS Suspend Supported PASS - DPMS Active Off Supported **************************************************************** **** <-x-Basic Display Parameters/Features-x-> <---Color Characteristics---> Red x: 0.644531 Red y: 0.320313 Green x: 0.273438...
  • Page 38 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification - 1280x1024 @75Hz ***************** Timing Support Check for 640x480 @75Hz ******* ********** PASS - 640x480 @75Hz support established **************************************************************** ********** ***************** Timing Support Check for 800x600 @75Hz ******* ********** PASS - 800x600 @75Hz support established...
  • Page 39 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification **************************************************************** ****** End of EDID Test Log EDID Test Log file closed 08/09/00 - 08:34:46 Note 6 EDID test (W2K) 8/9/00 8:34:46 AM EDID test (W2K): Info retrieved from edidw2k.log by TSHELL...
  • Page 40 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 120: 20 20 20 20 20 20 00 AA Monitor Type: CRT Connector Type: VGA Testing 17 inch monitor Decoded EDID data <---Header---> veHeader: 00 FF FF FF FF FF FF 00 <-x-Header-x->...
  • Page 41 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Max Vert Image Size: 23 cm. Display Gamma: Display Type: RGB color display Features, Preferred Timing Mode: No Features, Preferred Timing Mode: In first detailed block Features, GTF support: DPMS Features, Stand-by:...
  • Page 42 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification - 640x480 @75Hz - 800x600 @56Hz - 800x600 @60Hz Established Timimgs 2: - 800x600 @72Hz - 800x600 @75Hz - 1024x768 @60Hz - 1024x768 @70Hz - 1024x768 @75Hz - 1280x1024 @75Hz ***************** Timing Support Check for 640x480 @75Hz *****************...
  • Page 43 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Detailed Timing: FD (Monitor limits) Vert: 50 - 120 Hz Horz: 30 - 86 KHz Clk: 150 MHz <-x-Detailed Timing Descriptions-x-> Extension Flag: Checksum: ************************** EDID Test Report ************************** Congratulations - This Monitor has Passed the EDID Test...
  • Page 44 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 1.3.4 Metallization of Plastic Housing: *The plastic housing shall have neither internal nor external metallization.
  • Page 45 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification B. CRT Display Part 1: Visual Ergonomic - Legibility 1.3 Linearity: * <= 1%, (See Fig.5 & Fig.6) 1.4 Orthogonality: * H/V: <= 2%, Diagonal: <= 3% 1.5.1: Display Luminance: * >=100cd/m (80% Loading) 1.5.2 Luminance Uniformity: * <...
  • Page 46 MEA 1786FD2 CRT Monitor Service Guide Engineering Specification Part 3: Emission and Energy Saving 3.1 X-Ray : * < 0.5 mR/Hr 3.2 Electrostatic Potential: * <+-0.5KV 3.3 Electric Field (AC): * Band I < 10V/m (100cd/m , “+” Pattern) * Band II< 1V/m (100cd/m , “+”...
  • Page 47 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory DEFLECTION CIRCUIT OPERATION THEORY 1. The Block Diagram of Deflection : H-sync Digital Tilt Rotation Coil V-sync Controller Circuit I2C BUS AutoSync Deflection Controller IC TDA4856 Vertical Deflection Step Up Output G1 &...
  • Page 48 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 2. Autosync Deflection Controller (TDA4856) 2.1 pin 1 is AFC feedback . 2.2 pin XRAY: if V XRAY > threshold (6.25V typical) switches the whole IC into protection mode. 2.3 pin 3,4,5,6,8 for B+ control function block.
  • Page 49 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3. H-Driver & Output CKT : 3.1 HDRV signal comes from IC201 pin8 , then goes into Q301, Q301 constitutes an inverting stage and combines with T302 to drive Q302. 3.2 Q302, C306,C309, D305, C350 constitute the H-output CKT with diode modulator mode.
  • Page 50 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 4. Dynamic focus CKT According to the CRT spec H dynamic focus Vpp = 350 V H dynamic focus Vpp = 150 V 4-1 Vertical dynamic focus The signal from IC201 (pin 32) is a vertical frequency parabolic waveform.
  • Page 51 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 5.2 Blanking CKT To avoid the disturbed picture display on the screen , we have to blank the monitor in the following situations. (1) when display mode is changed. (2) when the monitor enter the power saving mode.
  • Page 52 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 6. BDRV and step-up CKT 6.1 The "BDRV" signal from TDA4856 pin6 is a square waveform. It is inverted and amplified by Q201. Q310 and Q311 constitute a buffer stage. 6.2 Q312, L301, D318, C323 is step-up circuit B+ = 50V * ( ton + toff ) / toff.
  • Page 53 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 7. HV Shutdown Circuit The IC201 pin2 (XRAY) provides a voltage detector with a threshold . If the voltage at pin XRAY exceeds this threshold (6.25v typical) the pins HDRV, BDRV, VOUT1 and VOUT2 are floating.
  • Page 54 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 8.Horizontal linearity CKT G781 Cs control truth table Frequency range SC5 SC2 SC1 SC0 Cs Capacitor Fh ¡ Õ C313 +C349+C311+C314+C312 36K ¡ Õ Fh ¡ Õ 40K C313+C312 40K ¡ Õ Fh ¡ Õ 51K C313 +C349+C311+C314 51K ¡...
  • Page 55 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 9. ABL CIRCUIT When the beam current is over the limited current , the ABL circuit will pull down the voltage of the video preamp (pin 11) to reduce the gain of video amplifier.
  • Page 56 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 10. TILT CKT We can rotate raster clockwise or counterclockwise by changing the direction of the current flow through the tilt coil. When the voltage of MP202(pin3) is larger than 6.5V, the current flows from Q205 to Tilt coil, other...
  • Page 57 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 11. Vertical Output Circuit This vertical driver IC circuit is a bridge configuration The signals from TDA4856 differential output VOUT1 and VOUT2 are connected to TDA4866 via DC-Coupled. The vertical deflection coil is connected between the output amplifier (TDA 4866 pin4 and Pin6 ) ,Which are driven in phase opposite .
  • Page 58 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory Switching Power Supply Operation Theory 1. General Specification Input Voltage : 90~264VAC (FULL RANGE) Input Frequency : 47~63Hz Output Requirement: Output MAX. Load Current +6.3V 0.7A +13V 1.0A +80V 0.15A +45V 1.0A...

  • Page 59: Circuit Operation Theory

    MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3.2 Rectifier and filter D602~D605 20D6 * 4 AC INPUT C612 220U DC OUTPUT 400V (EL) When power switch is turn on, the AC voltage is Rectifier and filter by D602~D605, C612. The DC output voltage will be 1.4*(ac input)
  • Page 60 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3.4 Output Rectifier and filter The structure of each output is illustrated as below T601 since the transformer T601 acts as a storing energy inductance, diode D1 and capacitor C1 are to...
  • Page 61 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3.5 Control circuit C625 R607 1N4004 (OPEN) 0.15 R611 VREF R613 R614 D611 IC601 ISSEN 100K 1N4148 UC3842 COMP C615 D612 2200P 1N4148 C619 ZD602 IC603 MCR100-3 (PE) 0.022U C620 C618...
  • Page 62 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory When power is initially applied to the circuit, capacitor C626 charges through R624, R623, ZD601. When the voltage across C607 reaches a level of 16V, IC601 is turn-on the +5Vdc will be...
  • Page 63 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3.7 DEGAUSS CIRCUIT D709 +12V 1N4148 C621 DEGAUSS D708 C708 R705 2200P 250V 1N4148 (OPEN) CN602 (EL) D603 RL601 R706 Q706 20D6 TR602 H945 4.7K 2R9M D604 L604 20D6 180UH D605...
  • Page 64 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 30. Video CKT VIDEO C.K.T. BLOCK DIAGRAM ¡ G DRIVE BIAS (FROM IC1901) (FROM IC 1901) R OSD DC RESTORE Q121,122 G OSD (FROM Q141,142 IC 1901 ) B OSD Q161,162...
  • Page 65 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory Output stage adopts CRT driver LM2439 to amplify the signal which has been recessed by LM1279 to a enough amplitude of Vpp, then display on the CRT. The IC contains three high input impedance, wide band amplifiers which directly drive the RGB cathodes of a CRT.
  • Page 66 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory negative voltage higher than CUT OFF to the G1 to beam this is to protect the CRT.
  • Page 67 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory MICROCONTROLLER CIRCUIT OPERATION THEORY 1. Introduction : This model will support powerful OSD function to help end user fine adjustment. The Microcontroller circuit can determine what mode it is by detecting the frequency of horizontal...
  • Page 68 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3.MCU and the peripheral circuit operation theory: 3-1.MCU function: The MCU is MTV112, it is an 87C51 with PWM output controlled microcontroller, after power on,the reset circuit output a "High" to "Low" signal(>40mS) and the 12MHz crystal oscillated circuit working , the MCU begin to manages the following functions, (1) To detect mode and output proper SC0, SC1 and SC2 to deflection circuit.
  • Page 69 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 3-3.What are the valid key functions for user: There are Five keys on control panel. They are "i-key, "Left," "Right," "Enter," and "Exit." The one, i-key, is for auto calibration function, the others are used for OSD controlling.
  • Page 70 MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory EEPROM. By this way, we can get the products with the same quality and reduce the manufacturing time.

  • Page 71: Preparation For Alignment

    MEA 1786FD2 CRT Monitor Service Guide Alignment Procedure Preparation for alignment : (I) Setup unit and keep it warm up at least 30 minutes (II) Signal mode Mode Frequency (H/V) Display 31.47k/70Hz (- /+ ) 640 * 400 (VGA400) 31.47k/60Hz (- / - ) 640 * 480 (VGA480) 53.6 k / 85Hz (+ /+ )
  • Page 72 MEA 1786FD2 CRT Monitor Service Guide Alignment Procedure 1. B¡ Þ Adjustment a. Input mode 79.98K [WS7] with crosshatch Pattern. b. Set contrast in OSD to maximal value and brightness in cut off. c. Adjust main board VR701, let output Voltage : 50 ± 0.2V at D704(near L702).
  • Page 73 MEA 1786FD2 CRT Monitor Service Guide Alignment Procedure 5. Focus adjustment a. Input mode 68.68K [UVGA8] with green crosshatch pattern b. Adjust V(F2) Focus VR of FBT to make vertical line between center and corner area of CRT clear c. Adjust H(F1) to make horizontal line between center and corner area of CRT clear d.
  • Page 74 MEA 1786FD2 CRT Monitor Service Guide Alignment Procedure 8. Clear all of user mode data After finishing all factory setting , Press enter or exit key to main menu. Press right or left key to scroll light bar to reset to default and press enter key, then at this time all of user mode data have been cleared 9.
  • Page 75 MEA 1786FD2 CRT Monitor Service Guide Alignment Procedure 11. Eyelet point define (1). Main board -C309(*2) -C612(*2) -IC202 Heat sink(*2) -Q602 Heat sink(*2) -C313(*3) -L302(*2) -Q602 “D”(*1) -L304 pin3, 4(*2) -M303(*4) -T301 pin1, 4, 8, 13 and 14(*5) (2). Video board -M105 pin5, 9, 11 and focus GND(*4) 12.

  • Page 76: Trouble Shooting

    MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting Check MCU and OSD for no video output: Check MCU and OSD for no video output Start Use a preset timing Check +5V, ok ? (1) On the Main Board, (a) IC801 pin40...

  • Page 77: Video Board

    MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting Check OSD,MCU for no OSD window: Check OSD, MCU for no OSD window Start Check +5V, ok? Check +5V power (1) IC1901(OSD IC) pin,6,19 Check Gnd & +5V and the R,C CKT Check IC1901(OSD IC) pin7(HBNK)&...
  • Page 78 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting Case 2: one or more of R, G, B channel does no display ¡ E Check IC101 pin 18,15,13. If anyone is 0 volt, replace a new IC to IC101. ¡ E Check RGB cathode. If anyone pin is 0 volt, replace a new IC to IC102.
  • Page 79 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting ¡ E Check H-blank circuit ¡ E Case 14: H-blank phase error 3.NO OUTPUT POWER NO OUTPUT Check F601 Check Replace F601 Check Replace D603~D606 FR705,D702 Replace D603~D606 Q602,R607? Q602,R607 D704,D705? Replace...
  • Page 80 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 4. No Raster HV ABNORMAL NO RASTER M103 CONNECTOR CHECK CHECK FR705 LOOSE. (ON V/B) LED LIGHT =45V POWER SUPPLY CHECK POWER SAVING CHECK G1 VOLTAGE CHECK G1 = 0 VDC Q302...
  • Page 81 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 5. H.V. ABNORMAL H.V. ABNORMAL CHECK C309,C306 YOKE CONNECTOR LINEAR COIL L304 CORRECT IT! CHECK FBT PIN2 AT VGA(31K) ABOUT 63V ? CHECK Q312,D318 CHECK DRIVER CKT REPLACE T302,L301 CHECK IC201 CHECK FBT(T301)
  • Page 82 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 6. CHECK IC201(TDA4856) DEFLECTION OUTPUT ABNORMAL CHECK PIN10(VCC) =12V ? CHECK PIN6,PIN8 OUTPUT (FREQ & DUTY) CHECK +14V CHECK CHECK PIN30 Q301,Q310,Q311 >4.4V ? Q201 CHECK Q701 EMITTER CHECK CHECK =14V R251,R253...
  • Page 83 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 7. PINCUSHION NG TRAPEZOID NG UNBALANCE NG GEOMETRIC FUNCTION NG PARALLEGRAM NG CHECK MCU,IF OK REPLACE IC201 H-PHASE V-CENTER NG 8. NO VERTICAL OUTPUT & RETRACE LINE NO BLANKING NO VERTICAL OUTPUT...
  • Page 84 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 9. SPOT KILLER NG SPOT KILLER NG CHECK -190V CHECK -190V TRACE CHECK Q203 CIRCUIT CHECK G1 VOLTAGE G1< -50VDC IF IT BECOMES CHECK CONNECTOR VERY LOW (LESS THAN G1 VOLTAGE -120VDC) WHEN POWER SWITCH OFF.
  • Page 85 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 10. FOCUS NG FOCUS NG CHECK IC201 PIN32 WAVEFORM CHECK FOCUS TRACE CHECK H-PARA SIGNAL CHECK Q321 FOCUS C329,R327 REPLACE REPLACE REPLACE COMPONENT REPLACE IC201 CHECK CS-1,CS-2 SIGNAL FOIL TRACE...
  • Page 86 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 11. HORIZONTAL SIZE CAN NOT CONTROL HORIZONTAL SIZE CAN NOT CONTROL CHECK Q314,Q315,Q316 REPLACE CHECK Q317,Q318 CHECK IC201 CHECK UC CIRCUIT PIN11 ABOUT para wave CHECK +12V REPLACE REPLACE 12.BRIGHTNESS CAN NOT CONTROL...
  • Page 87 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 13. SIZE REGULATION NG SIZE REGULATION NG H SIZE H & V SIZE REGULATION NG REGULATION NG CHECK ABL CIRCUIT CHECK REGULATION CIRCUIT FROM FBT PIN 8 R329,C324,R330,HMOD,VMOD R330 V SIZE REGULATION NG MAIN BOARD H.V.
  • Page 88 MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 15. No Blanking No Blanking IC801 pin 6 has output Check Q202 Trace open. & Ambient...
  • Page 89 Diamond View 1786FD2 (Main) (1 of 4)
  • Page 90 Diamond View 1786FD2 (main) (2 of 4)
  • Page 91 Diamond View 1786FD2 (main) (3 of 4)
  • Page 92 Diamond View 1786FD2 (Main) (4 of 4)
  • Page 93 Diamond View 1786FD2 Video PCB...
  • Page 94 Diamond View 1786FD2 Video PCB...

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