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Mitsubishi Electric 1786FD2, Service Manual

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Mitsubishi Electric 1786FD2 Service Manual Download Page 67

MEA 1786FD2

 CRT Monitor Service Guide 

Circuit Operation Theory

 

 

 
 

 21 

 

 

 

 

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 
and vertical synchronous and the polarity of horizontal synchronous, and provide DC voltages to 
control the  

picture and save the adjusted value into the EEPROM by using the OSD, "On 

Screen Display control", that means the user can get any information of the picture display or 
adjust it and save the status values into the EEPROM by choosing and pressing the proper key 
according to the indication of the OSD. In addition, user can press i-key to do auto-calibration. 

 
 2. 

Block diagram :

 

The major parts of Microcontroller circuit are MCU, EEPROM, OSD IC, and Auto Calibration 

Module. The circuit block diagram is shown as below. 

 
 

MCU

(MTV112)

Hsync
Vsync

H-polarity

Preset mode

User saved mode

Searching for

the same saved

mode timing

with the input

signals and

get the data.

Detecting the

input signals

of H,Vsync &

H-polarity.

Control Panel

5 keys

i-key

Left,Right,Enter,Ex

Checking if the

valid key be pressed

and do key function.

Degaussing
Blanking
SC0 - SC2

PWM

output

OSD IC

To deflection
circuit

(UART)      External
 adjustment

function

PC

RS232

auto alignment

program

Display OSD

and output

PWM to video

circuit

EEPROM

Reset circuit

12MHz Crystal

circuit

SCL

SDA

HBNK

VBNK

RGB

Signal

 

 

 

Summary of Contents for 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: ...l or otherwise without the prior written permission of the Company Disclaimer The Company makes no representations or warranties either expressed or implied with respect to the contents hereof and specifically disclaims any warranties merchantability or fitness for any particular purpose Further the Company reserves the right to reserve this publication and to make changes from time to time in the...

Page 3: ...Diamond View 1786FD2 Manual Contents Section 1 Engineering Specifications 2 Circuit Operation Theory 3 Alignment procedure 4 Trouble Shooting 5 Schematic Diagrams ...

Page 4: ...RONMENT RELIABILITY 5 3 CRT CHARACTERISTICS 6 4 FRONT OF SCREEN 6 4 1 GEOMETRY 6 4 2SHARPNESS CRISPNESS 7 4 3 LIGHT QUALITY 7 4 4 IMAGE STABILITY 7 5 USER CONTROLS 8 5 1 BASIC 8 5 2 ADVANCED 8 6 MECHANICAL CHARACTERISTICS 9 6 1 DIMENSION 9 6 2 WEIGHT 9 6 3 PLASTIC 9 6 4 CARTON 9 7 PALLET SHIPMENT 10 7 1 DIMENSION 10 7 2 SHIPPING CONTAINER 10 7 3 AIR TRANSPORT CONTAINER 11 8 CERTIFICATION 11 9 APPE...

Page 5: ...MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 2 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: ...consumption On 100 W max LED Green DPMS Standby 5 W LED Amber Suspend 5 W LED Amber Off 5 W LED Amber Inrush Current 110 VAC 50Hz 40 Amp peak cold start Leakage Current 264 VAC 50Hz 3 5mA Hi Pot 1 1500VAC 1 sec 2 Ground test 30A 1sec w o damage 0 1 ohm in line test in lab test Power cord Length 1800 mm Color Flint Gray KC 003 1 2SIGNALINTERFACE Condition Spec OK N A Remark Pin assignment 5V on Pin...

Page 7: ...reset Resolution Fh KHz Fv Hz OK N A Remark VGA400 640x400 31 47KHz 70Hz VGA480 640x480 31 47KHz 59 94Hz 6448A 640X480 37 5KHz 75Hz 6448B 640X480 43 269KHz 85Hz SVGA4 800x600 46 88KHz 75Hz SVGA3 800x600 48 09KHz 72 01Hz SVGA5 800x600 53 67KHz 85Hz Apple 16 832x624 49 71KHz 74 533Hz UVGA2 1024x768 56 476KHz 70 069Hz UVGA7 1024x768 60 023KHz 75 029Hz Super MAC 19 1024x768 60 24KHz 75Hz UVGA8 1024x76...

Page 8: ... Random Vibration Package Non Operating 5 100Hz 0 dB Oct 0 015g2 Hz 100 200Hz 6 dB Oct 200Hz 0 0038g2 Hz Non package Non Operating 20Hz 2000 0 0185g2 Hz Drop With packing Package Non Operating 19 4kg 61cm Height 1 corner 3 edges 6 faces Electrostatic Discharge IEC801 2 standard Contact 8KV Air 15KV 0 5 8KV tip table no blanking Acoustical Noise 40 dB A Power Line Transient IEC801 4 IEC1000 4 4 Cou...

Page 9: ...ng as approval sheet see table 2 4 Front of Screen 4 1 GEOMETRY OK N A Remark Magnetic Environment Northern Hemisphere H 0 0 05 V 0 45 0 05 Southern Hemisphere H 0 0 05 V 0 45 0 05 Equatorial H 0 0 05 V 0 0 05 Size Hor 310 4 mm Ver 230 4 mm Centering Hor Ver A B C D 4 mm See table 4 Geometric Distortion Top Bottom Side Pincushion 2 mm See table 5 for TCO99 Top Bottom Side Barreling 2 mm Hor Ver Tr...

Page 10: ...A Remark White Balance Full white center Brit cut off Cont max x 0 283 0 010 y 0 297 0 010 UVGA8 1024x768 68 68KHz 85Hz Purity W R G B X max X min Y max Y min 0 015 Color Tracking Brightness cut off x y nominal 0 015 Max Brightness with ABL Full white pattern 28Ft L min Cut off Max Brightness no ABL 3 Block 40Ft L min Cut off Brightness Uniformity Full white pattern 70 center to corner Raster ligh...

Page 11: ...itch Contrast Brightness H Size H Position V Size V Position Barrel Pincushion Parallelogram Trapezoid I Key 5 2 ADVANCED Function Spec OK N A Remark OSD position See Table 3 Color Gain Corner Pin balance Tilt Color Temp C1 C2 9300K 6500K Manual Degauss Recall Languages 5 languages Mis convergence adj Moire adj D sub BNC switch ...

Page 12: ... Tilt 4 12 degree Swivel 45 45 degrees 6 2 WEIGHT Spec OK N A Remark Monitor Net 16 4 Kg Monitor w packaging Gross 19 4 Kg 6 3 PLASTIC Spec OK N A Remark Flammability UL 94 V0 Heat deflection To ABS PC ABS 65 70 UV stability ABS PC ABS Delta E 5 after 300Hr Xted test Delta E 1 5 after 300Hr Xted test MPR2 Model TCO Model Resin MPR2 ABS TCO PC ABS Texture RE 6625 Color Light Gray 6 4 CARTON Spec OK...

Page 13: ... X X Air Transport Pallet Length 1150 1725 X Dimension mm Width 1080 1080 X Height 120 120 X 7 2 Shipping Container Stowing Type Quantity of products sets Quantity of Products sets Quantity of pallet sets Every container Every Pallet Every Container 20 160 Pallet A 16 Pallet A 10 Pallet B X Pallet B X With pallet 40 352 Pallet A 16 Pallet A 22 Pallet B X Pallet B X 20 160 X X X X Without pallet 40...

Page 14: ...6 Pallet A 2 Pallet B 24 Pallet B 2 8 Certification Condition Spec OK N A Remark Environment Green design API Doc 715 C49 ISO14000 Requirement Blue Angel German Standard E 2000 Switzerland NUTEK Swedish Standard EPA USA Standard EN61000 3 2 Harmonics TCO92 95 TCO99 PC Monitor Microsoft Windows PC98 99 DPMS VESA DDC 1 2B Version 3 0 USB External Safety UL USA UL 1950 3rd edition CSA Canada C22 2 No...

Page 15: ...n NOM Mexico IAA Korea EMC CE Mark 89 336 EEC FCC USA Class B EN55022 Class B CISPR 22 Class B VCCI Japan Class B BSMI Taiwan C Tick Australia AS3548 RRL Korean X Ray Requirement DHHS 21 CFR USA X Ray Standard DNHW PTB German X Ray standard MPRII EN50279 MPRIII Ergonomics 2 PfG 1041 1299 German ergonomic ISO 9241 3 7 8 ...

Page 16: ... code 0C ID Serial Number 0D 32 bits serial no 0E use 0 if n a 0F 10 Week of Manufacture 0 53 use 0 if n a 11 Year of Manufacture year 1990 12 01 EDID version 13 03 Revision 14 08 Video Input Define 15 1F Max H Image Size cm 16 17 Max V Image Size cm 17 gamma 100 100 18 EA DPMS 19 Red Green Bits Rx1Rx0Ry1Ry0Gx1Gx0Gy1Gy0 1A Blue White Bits Bx1Bx0By1By0Wx1Wx0Wy1Wy0 1B Red x bit9 2 1C Red y bit9 2 1D...

Page 17: ...MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 14 21 White x bit9 2 22 White y bit9 2 ...

Page 18: ... 30 01 6 31 01 32 01 7 33 01 34 01 8 35 01 36 EA Detailed Timing Description 1 37 24 38 00 Pixel clock 94 5Mhz 39 60 Hor Display 1024 pixels 3A 41 Hor Blanking 352 pixels 3B 00 Hor Front porch 48 pixels 3C 28 Hor Back porck 208 pixels 3D 30 Hor Sync pulse 96 pixels 3E 30 Hor Border 0 pixels 3F 60 Hor Size 310 mm 40 13 Ver Display 768 lines 41 00 Ver Blanking 40 lines 42 36 Ver Front porch 1 lines ...

Page 19: ...MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 16 47 00 ...

Page 20: ...ta Description 48 00 49 00 4A 00 4B FC Monitor name Acer G781 4C 00 4D 41 A 4E 63 c 4F 65 e 50 72 r 51 20 52 47 G 53 37 7 54 38 8 55 31 1 56 0A 57 20 58 20 59 20 5A 00 SN 00001 5B 00 5C 00 5D FF 5E 00 5F 30 60 30 61 30 62 30 63 31 64 0A 65 20 66 20 67 20 68 20 69 20 6A 20 6B 20 ...

Page 21: ...fication 18 Address Data Description 6C 00 6D 00 Range limit 6E 00 V Freq range 50 120Hz 6F FD H Freq range 30 86KHz 70 00 Max pix clock 150 MHz 71 32 72 78 73 1E 74 56 75 0F 76 00 77 0A 78 20 79 20 7A 20 7B 20 7C 20 7D 20 7E 00 Extension Flag 7F Check sum ...

Page 22: ... y bit9 2 1D 46 Green x bit9 2 1E 97 Green y bits9 2 1F 24 Blue x bit9 2 20 10 Blue y bit9 2 21 48 White x bit9 2 22 4C White y bit9 2 Samsung MPRII Tube 17 BE gamma 100 100 18 DPMS 19 03 Red Green Bits Rx1Rx0Ry1Ry0Gx1Gx0Gy1Gy0 1A 9E Blue White Bits Bx1Bx0By1By0Wx1Wx0Wy1Wy0 1B A5 Red x bit9 2 1C 52 Red y bit9 2 1D 46 Green x bit9 2 1E 97 Green y bits9 2 1F 24 Blue x bit9 2 20 10 Blue y bit9 2 21 4...

Page 23: ... y bit9 2 1D 4A Green x bit9 2 1E 9C Green y bits9 2 1F 27 Blue x bit9 2 20 10 Blue y bit9 2 21 47 White x bit9 2 22 4F White y bit9 2 Philips TCO99 Tube 17 A7 gamma 100 100 18 DPMS 19 94 Red Green Bits Rx1Rx0Ry1Ry0Gx1Gx0Gy1Gy0 1A A4 Blue White Bits Bx1Bx0By1By0Wx1Wx0Wy1Wy0 1B 9E Red x bit9 2 1C 58 Red y bit9 2 1D 4A Green x bit9 2 1E 9C Green y bits9 2 1F 27 Blue x bit9 2 20 10 Blue y bit9 2 21 4...

Page 24: ...Wx1Wx0Wy1Wy0 1B A2 Red x bit9 2 1C 55 Red y bit9 2 1D 47 Green x bit9 2 1E 99 Green y bits9 2 1F 25 Blue x bit9 2 20 0F Blue y bit9 2 21 47 White x bit9 2 22 4F White y bit9 2 Note 1 Bit Bit Description 7 Analog Digital Signal Level 6 Signal Level Standard 6 5 Signal Level Standard 5 4 Setup 3 Sync Inputs Supported 3 2 Sync Inputs Supported 2 1 Sync Inputs Supported 1 0 Sync Inputs Supported 0 ...

Page 25: ...he level of reference white volts above blank followed by the level of the sync tips in volts below blank Bit 6 Bit 5 Operation 0 0 0 700V 0 300V 1 000V p p 0 1 0 714V 0 286V 1 000V p p 1 0 1 000V 0 400V 1 400V p p 1 1 Reserved TBD 4 Setup If set the display is set to expect a blank to black setup or pedestal per the appropriate signal level standard 3 0 Sync Inputs See Bit Operation below 3 Separ...

Page 26: ...uspend Bit 5 Active off Bit 4 3 Display Type 0 0 Monochrome gray scale display 0 1 RGB color display 1 0 Non RGB multicolor display example RGY 1 1 Undefined Bit 2 0 Reserved Set at 00h until defined Note 3 CRT Vender Red x y Green x y Blue x y Gamma SAMSUNG 0 645 0 321 0 274 0 593 0 143 0 064 2 9 ...

Page 27: ...Byte 2 bit Established Timings II 7 800 600 72Hz VESA 6 800 600 75Hz VESA 5 832 624 75Hz Mac II Apple 4 1024 768 87Hz interlaced IBM 3 1024 768 60Hz VESA 2 1024 768 70Hz VESA 1 1024 768 75HZ VESA 0 1280 1024 75HZ VESA Byte 3 bit Manufacturer s Timings Manufacturer s Specified Timing 7 1152 870 75Hz Mac II Apple 6 640 480 85HZ 5 800 600 85HZ 4 1024 768 85HZ 3 1280 1024 85HZ 2 1600 1200 75HZ 1 1600 ...

Page 28: ...o of Blemishes Allowable Minimum Separation Blemishes Zone A Zone B Total Zones A B Zone A Zone B A 1 trio 1 1 2 B 1 0 0 0 2 0 2 2 20 C 3 1 2 2 20 Green 3 4 Red 5 6 D 1 dot Blue 5 6 6 50 20 1 3 or more consecutive same color phosphor dots 2 2 consecutive same color phosphor dots 3 2 consecutive different color phosphor dots Table 3 OSD Menu Please refer to Release 001 C01 ...

Page 29: ...ice Guide Engineering Specification 26 Table 4 Geometry Fig Fig 1 Linearity Measurements X1 X2 X3 X4 X6 X7 X8 X9 X10 X11 X18 Y0 Y1 Y2 Y3 Y4 Y5 Y8 Y10 Y7 Y6 Y11 Y12 Y13 X5 Y9 Xmax Xmin x 100 5 Xmax Xmin Ymax Ymin x 100 5 Ymax Ymin ...

Page 30: ... Engineering Specification 27 Fig 2 General Pincushion Measurements P Amm a1 S b2 R a2 Q 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 B by PQ RS 2 ...

Page 31: ...ice Guide Engineering Specification 28 Fig 3 Trapezoid Measurements 2 5 2 5 2 5 2 5 2 5 2 5 2 5 2 5 D C A B Each of the 4 corners of picture shall fall within the relevant area F illustrated up hatched ABCD is the picture outlines ...

Page 32: ...Service Guide Engineering Specification 29 Fig 4 Picture Distortion Phase Measurements b2 a1 b1 a2 Tilt orthogoal A B C D V2 H2 Peak Total H1 V1 D1 D2 02 0 2 1 5 0 2 1 H H H H 02 0 2 1 5 0 2 1 V V V V 03 0 2 1 5 0 2 1 D D D D ...

Page 33: ... Engineering Specification 30 Fig 5 TCO 99 Pincushion Measurements A C E G x1 x2 y2 y1 B x y 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 34: ...eling Measurements A C E G x1 x2 y2 y1 x y 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 Note 5 EDID test W2K 8 9 2000 8 34 46 AM EDID test W2K Info retrieved from edidw2k log by TSHELL ...

Page 35: ...20 08 1F 17 BE EA 03 9E A5 52 46 30 97 24 10 47 4F AF CF 00 45 59 40 61 59 01 01 01 01 01 01 01 01 50 01 01 01 01 EA 24 00 60 41 00 60 28 30 30 60 13 00 36 E6 10 00 70 00 00 00 00 00 FC 00 41 63 65 80 72 20 47 37 38 31 0A 20 20 20 90 00 00 00 FF 00 30 30 30 30 31 100 0A 20 20 20 20 20 20 20 00 00 110 00 FD 00 32 78 1E 56 0F 00 0A 120 20 20 20 20 20 20 00 AA Monitor Type CRT Connector Type VGA Test...

Page 36: ...n 3 x EDID Structure Version Revision x Basic Display Parameters Features Video i p definition Analog Setup Blank to Black not expected Seperate Syncs support Yes Composite Sync support No Vsync Pulse serration not required Max Horz Image Size 31 cm Max Vert Image Size 23 cm Display Gamma 2 9 Display Type RGB color display Features Preferred Timing Mode No Features Preferred Timing Mode In first d...

Page 37: ...Characteristics Red x 0 644531 Red y 0 320313 Green x 0 273438 Green y 0 592773 Blue x 0 142578 Blue y 6 34766e 002 White x 0 280273 White y 0 310547 x Color Characteristics x Established Timings Established Timimgs 1 AF 720x400 70Hz 640x480 60Hz 640x480 72Hz 640x480 75Hz 800x600 56Hz 800x600 60Hz Established Timimgs 2 CF 800x600 72Hz 800x600 75Hz 1024x768 60Hz 1024x768 70Hz 1024x768 75Hz ...

Page 38: ...ablished Timings 3 00 x Established Timings x Standard Timing Identification Standard Timing 800x600 85Hz Standard Timing 1024x768 85Hz x Standard Timing Identification x Detailed Timing Descriptions Detailed Timing 1024x768 84Hz Detailed Timing FC Monitor name Acer G781 Detailed Timing FF Monitor SN 00001 Detailed Timing FD Monitor limits Vert 50 120 Hz Horz 30 86 KHz Clk 150 MHz x Detailed Timin...

Page 39: ...ws CheckSum validation PASS Checksum valid Proceeding with test 128 bytes EDID Data Hex 0 1 2 3 4 5 6 7 8 9 0 00 FF FF FF FF FF FF 00 06 09 10 05 98 00 00 0F 00 00 0A 01 03 20 08 1F 17 BE EA 03 9E A5 52 46 30 97 24 10 47 4F AF CF 00 45 59 40 61 59 01 01 01 01 01 01 01 01 50 01 01 01 01 EA 24 00 60 41 00 60 28 30 30 60 13 00 36 E6 10 00 70 00 00 00 00 00 FC 00 41 63 65 80 72 20 47 37 38 31 0A 20 20...

Page 40: ...D Product Code Product Code Validation PASS Product code valid ID Serial Number 000F0000 Week of Manufacture 0 Year of Manufacture 2000 x Vendor Product Identification x EDID Structure Version Revision EDID Version 1 EDID Revision 3 x EDID Structure Version Revision x Basic Display Parameters Features Video i p definition Analog Setup Blank to Black not expected Seperate Syncs support Yes Composit...

Page 41: ...S Features Stand by Yes DPMS Features Suspend Yes DPMS Features Active Off Yes 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 Green y 0 592773 Blue x 0 142578 Blue y 6 34766e 002 White x 0 280273 White y 0 310547 x Color Characteristics x Established Timings Est...

Page 42: ...t established Timing Support Check for 800x600 75Hz PASS 800x600 75Hz support established Timing Support Check for 1024x768 75Hz PASS 1024x768 75Hz support established Established Timings 3 00 x Established Timings x Standard Timing Identification Standard Timing 800x600 85Hz Standard Timing 1024x768 85Hz x Standard Timing Identification x Detailed Timing Descriptions Detailed Timing 1024x768 84Hz...

Page 43: ...any Process shall not use any Chlorinated Solvent substance 1 2 Environmental Hazards 1 2 1 Mercury and Cadmium in Electronic Components None of electronic components contain any mercury or cadmium 1 2 2 Flame Retardants in Plastic Components Plastic 25g shall not contain retardants of organically bound Chloride or Bromide 1 3 Preparation for Recycling 1 3 1 Labelling of Plastic Plastic 25g shall ...

Page 44: ...MEA 1786FD2 CRT Monitor Service Guide Engineering Specification 41 1 3 4 Metallization of Plastic Housing The plastic housing shall have neither internal nor external metallization ...

Page 45: ...Temperature Variations Δu v 0 01 of White 9300 o K 8500 10250 o K 7500 o K 6980 8100 o K 6500 o K 6100 6950 o K 5000 o K 4700 5350 o K and actual measured Pre set of Lower CCT should not exceed Higher CCT Reference White Color Spec in TCO 99 CCT oK x y u v 9300 0 283 0 297 0 189 0 446 7500 0 299 0 315 0 194 0 459 6500 0 313 0 329 0 198 0 469 5000 0 346 0 359 0 209 0 488 5600 1 7 2 Color Uniformity...

Page 46: ...rn Note Shielded Power Cord is not acceptable 3 4 Magnetic Field AC Band I 200 nT 100cd m2 Pattern Band II 25 nT 100cd m2 Pattern Note Shielded Power Cord is not acceptable 3 5 Energy Saving 1st stage 15W recover time 3 sec 2nd stage 5W Single stage 5W recover time 3 sec Monitor with USB Hub same as above or single stage 15W recover time 3sec Part 4 Acoustic Noise 4 1 Acoustic Noise VDUs with fan ...

Page 47: ...m of Deflection H sync V sync Digital Controller Tilt Circuit Rotation Coil I2C BUS AutoSync Deflection Controller IC TDA4856 Vertical Deflection Output IC TDA4866 H SIZE Compensation Dynamic Regulation Feedback Step Up for B Horizontal Deflection Output Circuit Shut down Circuit G1 Spot Killer Circuit Dynamic Focus G1 ...

Page 48: ... B control function block 2 4 pin 11 EWDRV is a parabolic waveform used for pincushion correction 2 5 pin 16 generates video claming blanking pulse 2 6 pin 18 19 is I2C data 2 7 pin 21 V regulation 2 8 the resistor from pin 28 HREF to ground determines the maximum oscillator frequency 2 9 the resistor from pin 27 HBUF to pin 28 defines the frequency range 2 10 pin 31 H regulation 2 11 pin 32 focus...

Page 49: ... 3 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 Fig 3 HDRV output circuit ...

Page 50: ...is a vertical frequency parabolic waveform Q321 an inverting amplifier stage 4 2 Horizontal dynamic focus The horizontal frequency parabolic waveform is amplified by T304 Fig 4 Dynamic Focus circuit 5 Brightness spot killer CKT 5 1 G1 CKT The bright control signal from UC controller is about 0 5V when the voltage of bright control signal increases the current flow through R241 increases and the vo...

Page 51: ...n display mode is changed 2 when the monitor enter the power saving mode 3 blank the vertical retrace line when the blank signal becomes high Q209 ON Q203 OFF G1 voltage is about 190 R253 R253 R241 184V The signal which is IC201 pin 16 is inverted and amplified by Q202 and coupling to G1 During the vertical retrace interval the G1 voltage will be drop down about 48V Fig5 Brite Spotkiller circuit ...

Page 52: ...Theory 6 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 Fig 6 BDRV Step up circuit ...

Page 53: ...ovides 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 When anode voltage increases the voltage at FBT pin3 increases the voltage at IC201 pin2 increases The shutdown voltage is about 28KV Fig 7 HV shutdown CKT ...

Page 54: ...KT G781 Cs control truth table Frequency range SC5 SC2 SC1 SC0 Cs Capacitor Fh 36K 0 0 0 0 C313 C349 C311 C314 C312 36K Fh 40K 1 1 1 0 C313 C312 40K Fh 51K 0 0 0 1 C313 C349 C311 C314 51K Fh 62K 0 0 1 1 C313 C349 C311 62K Fh 73K 0 1 1 1 C313 C349 73K Fh 86K 1 1 1 1 C313 Fig 8 Linear circuit ...

Page 55: ...rvice Guide Circuit Operation Theory 9 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 Fig 9 ABL circuit ...

Page 56: ...e 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 wise the current flows from tilt coil to Q206 Fig 10 TILT circuit ...

Page 57: ...gnals 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 The TDA4866 can output current to drive vertical deflection yoke PIN8 GUARD is used for vertical blanking Fig11 Vertical output circuit ...

Page 58: ...80V 0 15A 45V 1 0A 2 Block Diagram DEGAUSS CIRCUIT RFI FILTER RECTIFIER FILTER SWITCHING ELEMENT FEEDBACK CONTROL CIRCUIT ISOLATION TRANSFOR MER POWER SAVING CONTROL OUTPUT RECTIFIER AND FILTER OUTPUT AC INPUT 3 Circuit Operation Theorem 3 1 RFI FILTER 250V 2200P Y C602 3 4 1 2 L602 250V 2200P Y C603 L604 L603 250V 0 47U X C601 N FG L R601 This circuit designed to inhibit electric and magnetic int...

Page 59: ...FR704 FR701 T601 Q602 L608 L606 L607 C613 C624 C614 D610 D608 D614 R607 R608 R611 R604 R619 C608 OPEN OPEN SHORT SHORT SHORT FS14SM 12 BEAD BEAD BEAD D 1KV 0 01U D 1KV 220P OPEN EGP30B UF4007 RGP10D UF4007 2W 0 15 20K 1K 2W 82K 2W 470 25V 47U EL In a flyback converter operated in the discontinuous mode the energy stored in the flyback transformer actually an inductor must be zero at the beginning ...

Page 60: ...put Rectifier and filter The structure of each output is illustrated as below T601 C1 C2 D1 L1 since the transformer T601 acts as a storing energy inductance diode D1 and capacitor C1 are to produce a dc output and additional L1 C2 to suppress high frequency switching spikes ...

Page 61: ...16 UC3842 MCR100 3 24V 5 1V D 50V 0 022U D 50V 820P D 50V 0 01U OPEN 1N4148 1N4148 1N4004 10K 36K 2W 0 15 1K 51K 100K 47 1 2W 82 10K 510 50V 10U EL 50V 4 7U EL 50V 2200P PE 100V 0 01U PE 6 5VA The current mode control IC UC3842 is used in the switching power supply which function of each pin described as follows pin 1 Error amplifier output pin 5 Ground pin 2 Error amplifier reverse input pin 6 Ou...

Page 62: ...oft start components to avoid the duty too large when power starts up 3 6 Feedback circuit This power supply adopt feedback circuit of 45V and 13V It used IC702 for voltage regulation and IC602 for primary secondary isolation The output voltage differential signal will be detected and sensed to the pin2 of UC3842 for comparison then the duty cycle of MOSFET will be decided to control the output vo...

Page 63: ...egaussing When power supply is switched ON it is auto degaussing stage When user make the selection of the manual degaussing function in OSD the degaussing current will flow through coil to degauss the screen of monitor TR602 is a PTCR to control degaussing coil current 3 8 power saving control Mode H sync V sync LED Power Rating Normal Normal Normal Green 100 Stand by None Normal Orange 5W Suspen...

Page 64: ...fication of two amplifiers The first one preamp CKT process the signal and mix up the OSD and the second one does the power amplification b OSD preamp IC101 LM1279 will output the R G B signals seperately The R G B driver will control the gain of these three guns individually to approach the white balance of CRT c The signal H Blank is to let the output of LM1279 down to 0 2V while non display dur...

Page 65: ...CRT 35 H BLANK CKT Affair the collect pulse comes from FBT being shaped and inverted it will be sent to preamp CKT and used as the H Blank 36 Brightness V blank change mode blank spotkiller CKT a About the cut off voltage while the voltage cathode to G1 over the cut off voltage the picture will disappear If cut off voltage off the CRT G Gru is setted at 110V and the black level of cathode is 60v t...

Page 66: ...MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 20 negative voltage higher than CUT OFF to the G1 to beam this is to protect the CRT ...

Page 67: ...hoosing and pressing the proper key according to the indication of the OSD In addition user can press i key to do auto calibration 2 Block diagram The major parts of Microcontroller circuit are MCU EEPROM OSD IC and Auto Calibration Module The circuit block diagram is shown as below MCU MTV112 Hsync Vsync H polarity Preset mode User saved mode Searching for the same saved mode timing with the inpu...

Page 68: ...ode timing Only when the mode timing input is stable we can adjust the picture and check the horizontal and vertical sync frequency by the OSD menu and the mode timing input mean the horizontal sync signal and the vertical sync signal 1 The vertical sync frequency measurement We use the base timer it can generate a count during a fixed time this fixed time is 12 12MHz and we call it Time_base so w...

Page 69: ...aving user adjusted data the other is for common settings area where stored the data of the OSD color temperature settings contrast and brightness value 3 5 How to display the OSD menu The OSD IC is AP3114 AP315 which is developed by vender it receives the data of the OSD fonts and attribute what we want to display on the screen from the MCU by 2 wires of communication and exports OSD window data ...

Page 70: ...MEA 1786FD2 CRT Monitor Service Guide Circuit Operation Theory 24 EEPROM By this way we can get the products with the same quality and reduce the manufacturing time ...

Page 71: ...alignment I Setup unit and keep it warm up at least 30 minutes II Signal mode Mode Frequency H V Display 1 31 47k 70Hz 640 400 VGA400 2 31 47k 60Hz 640 480 VGA480 3 53 6 k 85Hz 800 600 SVGA5 4 60 0 k 75Hz 1024 768 UVGA 7 5 68 6 k 85Hz 1024 768 UVGA8 6 79 98k 75Hz 1280 1024 WS7 ...

Page 72: ... Input mode 31 47K with crosshatch pattern b Use OSD to adjust H size maximum c Adjust VR301 to make H size just over screen above 16mm 4 Factory setting mode adjustment 1 H phase Set picture to the center of screen 2 H Size Set picture to 310 2 mm 3 V center Set picture to the center of screen 4 V size Set picture to 230 2 5 Parallelogram Set picture to rectangular or balance 6 Trapezoid Set pict...

Page 73: ...gnment A PREPARING ITEMS a PC b RS232 BOX c RS232 CABLE 9P TO PC d RS232 BOX TO MONITOR CABLE 3P e COLOR ANALYZER CA100 f CA100 CABLE TO PC g ADJUST PROGRAM Release NEW Version B Alignment procedure a Press SPACE BAR to get raster pattern and set contrast and brightness to maximum position adjust the G2 VR such that the max color of R G B color bar on the monitor is in the mark region b Press SPAC...

Page 74: ...nc signal from input the unit will go into Standby mode The picture will disappear and the LED indicator is amber The power consumption should be less than 5W d Remove vertical sync signal from the input the unit will go into Suspend mode The picture will disappear and the LED indicator is amber The power consumption should be less than 5W e Remove both syncs from input the unit will go into Off m...

Page 75: ...t 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 Touch up point define 1 Main board CN601 TR602 IC801 pin1 and pin 21 IC201 pin 1 and pin 17 IC202 pin 1 and pin 9 RL601 M602 Q312 Q302 D305 Q318 2 Video board M101 pin 1 and 13 M102 pin 1 and 11 M103 pin 1 and 9 ...

Page 76: ...1 2 On the Board IC1901 pin2 3 OSD IC DC level 1 3V 3 IC1901 pin11 pin18 output PWM Check F12M CKT on the Main Board on Main Board DC level 1 3V Check MCU IC801 Reset pin9 H to L ok Check IC801 BLANK L ok Check IC802 EEPROM ok Check 1 V FREQ circuit 2 H FREQ circuit 3 IC801 pin 13 15 Check 1 pin5 SDA 2 pin6 SCL 3 IC802 data EEPROM Brightness Contrast 1 On the Board a SCL IC1901 pin 10 b SDA IC1901...

Page 77: ...o destroy the set There assume that following cases depend on above setup OK Please follow as below and check it step by step Case 1 No video display on screen Check IC101 pin 10 Video Contrast If it is 0 volt check IC1901 or maybe IC101 pin 10 short Check IC101 pin 18 15 13 If they are 0 volts replace a new IC to IC101 Check RGB cathode If anyone pin is 0 volt replace a new IC to IC102 Check IC10...

Page 78: ...l cannot adjust Bias Check IC1901 Check DC restore circuit Case6 OSD control cannot adjust Drive Check IC101 and IC1901 Case 7 OSD control cannot adjust Contrast Check IC 101 and IC1901 Case 8 OSD control cannot adjust Brightness Check brightness control circuit G1 and IC801 BRITE output Case 9 ABL cannot adjust Check ABL circuit Case 10 Spot killer function failure Check SG101 300KV spark gap Rep...

Page 79: ...nk phase error 3 NO OUTPUT POWER Check FR705 D702 D704 D705 Replace Q602 R607 Replace IC601 Replace IC603 IC602 Replace Check IC601 ZD602 ok Check F601 D603 D606 ok Check IC603 IC602 Check IC601 Check Q602 R607 Replace IC601 ZD602 Replace F601 D603 D606 No No No No Yes Yes Yes No No NO OUTPUT ...

Page 80: ... CHECK POWER SUPPLY NO RASTER HV ABNORMAL M103 CONNECTOR LOOSE ON V B NG NO YES CHECK G1 VOLTAGE G1 0 VDC CHECK FR705 45V LED LIGHT CHECK POWER SAVING CKT YES REPLACE NG OK CHECK Q302 REPLACE NG CHECK STEP UP CKT Q312 D318 OK NG OK CHECK POWER SUPPLY CHECK IC201 TDA4856 ...

Page 81: ...ble Shooting 6 5 H V ABNORMAL H V ABNORMAL CHECK FBT PIN2 AT VGA 31K ABOUT 63V CHECK C309 C306 YOKE CONNECTOR LINEAR COIL L304 REPLACE CHECK DRIVER CKT T302 L301 NG CHECK IC201 CHECK Q312 D318 OK CORRECT IT NG OK YES NO NG OK CHECK FBT T301 OK ...

Page 82: ...Q311 Q201 OK CHECK OUTPUT STAGE OK REPLACE NG CHECK PIN30 4 4V NG CHECK R215 R214 C210 YES REPLACE IC201 YES CHECK R251 R253 R249 C216 CHECK SUSPEND SIGNAL HIGH REPLACE NG YES CHECK Q702 NO CHECK POWER SUPPLY OK NG NG CHECK FBT T301 OK NO CHECK 14V CHECK Q701 EMITTER 14V YES CHECK POWER SUPPLY NO NO CHECK Q702 Q701 YES REPLACE NG CHECK 14V TRACE SHORT OK REPLACE SHORT COMPONENTS ...

Page 83: ...ERTICAL OUTPUT CHECK B CORRECT PIN 3 14V PIN 7 45V IF PIN3 FAILS CHECK FR223 IF PIN7 FAILS CHECK 45V FR234 NO CHECK IC201 TDA4856 PIN12 PIN13 OUTPUT CORRECT YES REPLACE REPLACE IC202 TDA4866 OK NG CHECK R275 R274 YES REPLACE IC201 TDA4856 NO OK NG NO VERTICAL BLANKING CHECK IC202 TDA4866 PIN8 OUTPUT CORRECT REPLACE IC202 TDA4866 NG CHECK IC201 TDA4856 PIN16 OUTPUT CORRECT OK REPLACE IC201 TDA4856 ...

Page 84: ...G CHECK 190V CHECK Q203 CIRCUIT CHECK 190V TRACE YES NO CHECK CONNECTOR G1 VOLTAGE CHECK G1 VOLTAGE IF IT BECOMES VERY LOW LESS THAN 120VDC WHEN POWER SWITCH OFF OK G1 50VDC G1 0 VDC YES CHECK Q202 CHECK Q202 CHECK BLANK SIGNAL UC CKT CHECK R216 R217 R218 HOLDDOWN CKT REPLACE NG NG OK OK ...

Page 85: ...uble Shooting 10 10 FOCUS NG FOCUS NG REPLACE IC201 CHECK IC201 PIN32 WAVEFORM CHECK FOCUS TRACE CHECK H PARA SIGNAL C329 R327 CHECK Q321 FOCUS CKT NG OK REPLACE NG OK NG CHECK CS 1 CS 2 SIGNAL FOIL TRACE REPLACE OK NG REPLACE COMPONENT NG OK ...

Page 86: ...OT CONTROL CHECK Q314 Q315 Q316 REPLACE NG CHECK Q317 Q318 YES NO CHECK IC201 PIN11 ABOUT para wave REPLACE YES CHECK 12V REPLACE CHECK UC CIRCUIT 12 BRIGHTNESS CAN NOT CONTROL BRIGHTNESS CAN NOT CONTROL CHECK BRITE SIGNAL ADJUSTABLE CHECK UC CIRCUIT NO CHECK C224 Q202 R241 Q203 R232 R231 48V 8V YES REPLACE YES NO ...

Page 87: ... H V SIZE REGULATION NG REPLACE FBT H V OK CHECK ABL CIRCUIT MAIN BOARD OK REPLACE R329 R258 R211 V SIZE REGULATION NG CHECK REGULATION CIRCUIT R329 C324 R330 HMOD VMOD CKT REPLACE THE FAILURE COMPONENTS 14 Unstable Vertical Display Unstable Vertical Display IC201 pin 24 sawtooth genentor N Y Check IC201 Ambient CKT IC 202 has output N Y Check IC202 Ambient CKT Check DY ...

Page 88: ...MEA 1786FD2 CRT Monitor Service Guide Trouble Shooting 13 15 No Blanking No Blanking IC801 pin 6 has output Check Q202 Ambient CKT Trace open ...

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