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Hitachi H972 Service Manual

High resolution color display monitor
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SERVICE MANUAL
CAUTION:
Before servicing this chassis, it is important that the service personnel must read the
"Safety Precautions" and "Product Safety Notice" in this Service Manual.
FEATURES ...........................................................................................................................2
SAFETY PRECAUTIONS......................................................................................................2
CHECK OF HIGH VOLTAGE HOLD DOWN CIRCUIT.........................................................2
PRODUCT SAFETY NOTICE...............................................................................................3
SPECIFICATIONS ................................................................................................................3
CONTROLS ..........................................................................................................................4
SIGNAL TIMING CHART ......................................................................................................5
DESCRIPTION OF CIRCUIT .................................................................................................7
TROUBLESHOOTING...........................................................................................................16
ADJUSTMENTS..................................................................................................................20
WIRING DIAGRAM.............................................................................................................24
BLOCK DIAGRAM ..............................................................................................................25
P.C.B.A. ASSEMBLY ..........................................................................................................26
DISPLAY ASSEMBLY.........................................................................................................45
ATTACHMENT A ................................................................................................................54
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.
HIGH RESOLUTION COLOR DISPLAY MONITOR
YK
H972
(CM771U/ET)
(CM772U/ET)
DJ72 Chassis   
CONTENTS
(Sept. 2000)
SM 0401
(V1.0)

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  Summary of Contents for Hitachi H972

  • Page 1: Table Of Contents

    SM 0401 H972 (CM771U/ET) SERVICE MANUAL (CM772U/ET) DJ72 Chassis    (V1.0) CAUTION: Before servicing this chassis, it is important that the service personnel must read the “Safety Precautions” and “Product Safety Notice” in this Service Manual. CONTENTS FEATURES ...........................2 SAFETY PRECAUTIONS......................2...
  • Page 2: Features

    FEATURES Service Warning With minimum Brightness and Contrast the operating 1. Flat screen CRT with anti-glare, dynamic focus circuit, high voltage in this display is lower than 30 kV. dark glass, and INVAR shadow mask give the If any component having influence on the high voltage is sharpest focus and highest contrast.
  • Page 3: Product Safety Notice

    PRODUCT SAFETY NOTICE DC VOLT METER (10 V range) Many electrical mechanical parts in the color monitor units have special safety related characteristics. VARIABLE These are often not evident from visual inspection nor RESISTER can the protection afforded by them necessarily be 300 k -B (1/2 W) obtained by using replacement components rated for Clockwise...
  • Page 4: Controls

    CONTROLS Front Cover CRT Surface Power Switch Control Panel Tilt & Swivel Base FIG.3 FRONT VIEW FIG. 3 FRONT VIEW Power Switch Menu Key Adjustment Keys Power Indicator FIG. 4 CONTROL PANEL D-Sub Mini 15-pin AC Inlet Signal Cable (D-Sub Mini 15-pin) FIG.
  • Page 5: Signal Timing Chart

    SIGNAL TIMING CHART VESA VESA VESA Signal 640400 800600 1024768 12801024 (70Hz) (85Hz) (85Hz) (85Hz) CM771U-511 CM771ET-301 CM772U-511 CM772ET-301 Video Type R/G/B Analog R/G/B Analog R/G/B Analog R/G/B Analog Voltage 0.7 Vp-p 0.7 Vp-p 0.7 Vp-p 0.7 Vp-p Set Up None None None...
  • Page 6 VESA VESA Signal Adjustment 16001200 16001200 640480 signal (75Hz) (85Hz) (60Hz) CM771U-511 CM771ET-301 CM772U-511 CM772ET-301 Video Type R/G/B Analog R/G/B Analog R/G/B Analog R/G/B Analog Voltage 0.7 Vp-p 0.7 Vp-p 0.7 Vp-p 0.7 Vp-p Set Up None None None None Type H/V Separate H/V Separate...
  • Page 7: Description Of Circuit

    DESCRIPTION OF CIRCUIT 1. Power Supply Circuit This model incorporates a wide range universal power supply utilizing a switching regulator (see block diagram in Fig.6). 1.1 AC input AC input consists of AC inlet, EMI filter (C901C905,C907) and rectifier (D901D904). Rectifier circuits adapt to full-wave method.
  • Page 8 FIG. 6 BLOCK DIAGRAM FOR POWER SUPPLY CIRCUIT Main power supply Circuit #2 Chopper +85V Chopper +54V +14V Control AC inlet Circuit #1 Degauss Circuit On/Off control Circuit #3 + 6.3V Manual Degauss + 12V Chopper Reg. Control Heater On/Off On/Off control Standby power supply...
  • Page 9 2. Video Processing Circuit 2.1 Video select circuit (Optional) Two of Video input signals shall be switched at Video selector (I205) controlled by switching signal coming from microprocessor. 2.2 Video Processor The video input signal of 0.7 Vp-p is amplified to approximately 50 Vp-p by the video processing circuit and is fed to the cathode to drive the beam current.
  • Page 10: Horizontal Deflection Circuit

    3. Horizontal Deflection and High Voltage Regulation Circuit 3.1 Horizontal Deflection Circuit The purpose of the horizontal deflection circuit is to cause the CRT electron beam to be scanned horizontally by driving a current through the deflection yoke, synchronized by the H sync pulse. The circuit consists of an AFC circuit, made up of an H phase locked loop and VCO (voltage controlled oscillator), and the deflection output.
  • Page 11 FIG. 9 DEFLECTION CONTROL IC BLOCK DIAGRAM 1.2V EWDRV I701 OUT2 EW-Output V-Output Vertical H-Pincushion V-Linearity V-Sync V-sync OUT1 H-Corner V-Linearity Balance Oscillator H-Trapezium Integrator H-Size and AGC clamping Video V-Position blanking Clamping V-Size,VOVSCN V-BLANK FOCUS Focus Horizontal and Vertical HUNLOCK HUNLOCK Protection...
  • Page 12 3.2 High Voltage Regulation Circuit The output pulse from Q701 is also fed to the high voltage regulation circuit with the same design of consonant circuit as the horizontal deflection circuit. High voltage of 27.0 kV is obtained by the step-up windings of the flyback transformer to drive the CRT anode.
  • Page 13: Vertical Deflection Circuit

    4. Vertical Deflection Circuit The purpose of the vertical deflection circuit is to cause the CRT electron beam to be scanned vertically by driving a current through the deflection yoke, synchronized by the V sync pulse. V sync is input to the V oscillator circuit, I701, generating the vertical saw tooth wave.
  • Page 14 5. Microprocessor Circuit The microprocessor circuit consists of the following four detailed circuits as shown in Fig.12. 1. Sync detect circuit 2. Front panel key data Input / Output (I/O) 3. Processing and memory 4. Control output 5.1 Sync detect circuit The sync priority selector (I302) outputs H/V separate or composite sync signal to the sync processor inside the microprocessor (I101).
  • Page 15 FIG. 12 MICROPROCESSOR CIRCUIT 1.H/V Size Moiré Sync on Green 8.H/V 2.H/V Position 9.Dynamic Focus Sync 3.Pincushon 10.V.Linearity H/V Separate H/V sync Priority 4.Trapezoid Selector Deflection 11.V.L.Balance Control 5.Pin.Balance 12.Hemisphere Composite Sync H/V sync 6.Parallelogram 7.Top/Bottom corner Pin. 1.Contrast 2.Brightness 3.Color BKG R/G/B Polarity 4.Sub BKG...
  • Page 16 6. Power Save Function The DJ72 chassis is capable of power savings by sensing of the sync input conditions by the microprocessor. The microprocessor can identify two sync conditions, (1) No detection of H.sync, (2) No detection of V sync. The following table shows the details of the Power save mode.
  • Page 17: Troubleshooting

    TROUBLESHOOTING 1. Raster does not appear Relevant circuit : Power circuit, Horizontal deflection circuit, High voltage limitter circuit Check supply Abnormal Trouble outside the monitor Voltage AC100-200V/ AC 200-240V Normal Q910, Q902, I940 D901, D902, D903, D904 Abnormal Abnormal Check F901 Replace F901 C901, C902, C903, C904, C905, C907, C910, C920...
  • Page 18 2. Synvhronization is not obtained Relevant circuit : Sync. input circuit, Microprocessor, Deflection circuit H.SYNC is Check H.Sync. abnormal obtained I101, I104, I201, I302 H.SYNC and V.SYNC of I101 8pin and 9pin Q320, D26Z, D35Z V.Sync. (Change the DJ72 Video V.SYNC is Board or Main Board) normal...
  • Page 19 5. Color does not appear Relevant circuit : Video amplifier circuit Check Abnormal Trouble outside the the input signal. character monitor Normal Check D975, I971 the voltage of 12V (Change the DJ72 Main Board) Normal (12V) Abnormal Abnormal Abnormal Check the Check Check the I301, I101...
  • Page 20: Adjustments

    ADJUSTMENTS 1. Power supply 1.1 Standby power supply voltage adjustment. (1) Turn the switch of the unit off. (2) Place a jumper wire across R943, Q801 (G)-(S), I101(26pin) to GND, I740(13pin) to GND on main-p.w.b to disable Main power supply voltage. (3) Place resister 3.9k(31W) across C971(+) to GND (4) Receive reverse cross hatch pattern of signal 94A.
  • Page 21 2. Deflection circuit adjustment 2.1 SUB H.SIZE adjustment (1) Turn the switch of the unit off. (2) Connect a Digital multimeter across C771. (3) Turn the switch of the unit on. (4) Receive normal cross hatch pattern of signal 94A. (5) Adjust H.SIZE to maximum and S.Pincushion minimum by the Front Key.
  • Page 22: Video Circuit

    3. Video circuit Prior to the video circuit adjustment, all sync. and Deflection circuit adjustment must be completed. The monitor must have been warmed up for more than 60 minutes. Video signal must be terminated with 75 and should provide the correct voltage at the monitor end.
  • Page 23: Focus Adjustment

    X=0.281  0.008, Y=0.311  0.008 (Either Red color or Green color must be set to the maximum (FFh) ) (5) Register the readings of R/G/B BKG and Color dada (Color 1) to the microprocessor. 3.4 White balance adjustment (Color 3) (1) Receive a signal of 94A with a 100100 mm window pattern.
  • Page 24: Wiring Diagram

    WIRING DIAGRAM - 24 -...
  • Page 25: Block Diagram

    DJ72 BLOCK DIAGRAM 15P-DSUB R . G . B . G A I N C O N T R O L VIDEO OUT PUT CONTROL C L P CONT H. SYNC V. SYNC BUFFER Sync on G Sep. DDC5V CONT C-CONT SYNC S-BKG PRIORITY...
  • Page 26: P.c.b.a Assembly

    P.C.B.A ASSEMBLY WARNING 1) This product contains components which are critical for X-radiation safety. Read the Service manual carefully for proper replacement. Maximum 2nd anode voltage use high impedance meter, connect (-) to chassis, use a high voltage lead from (+) to 2nd anode. 2) Critical Components are marked with the symbol of in the material list.
  • Page 27 ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # 452A2488011 PCBA, CRT BOARD VQ-906 H972 1 442A2488011 AIS ASSY, CRT BOARD VQ-906 H972 1 - - - - ZZZ...
  • Page 28 ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # 442A2488011 AIS ASSY, CRT BOARD VQ-906 H972 1 432A2488011 SMT ASSY, CRT BOARD VQ-906 H972 1 - - - - ZZZ...
  • Page 29 =================================================================================================================== QUANTITY REQUIRED DWG.NO. 452a24 REV. 1D C NO. PART NO. DESCRIPTION SPECIFICATION ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- 36 CC4700211T2 RESISTOR 1/8W 470 +-5% 4 - - - - R307 R308 R84G R84R 37 CC4703011T5 RESISTOR 1/2W 470K +-5%...
  • Page 30 - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # 432A2488011 SMT ASSY, CRT BOARD VQ-906 H972 1 DA1H972V110 PCB H972 VQ-906 REV1A 1 - - - - BV1 2 SB32412K0T0 SM TRANSISTOR 2SC2412K (SM)
  • Page 31 - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ---------------------------------------------------------------------------------------- # 456A2488011 PCBA, DEF & POWER VA-906 MH972 1 446A2488011 AIS ASSY, DEF & POWER VA-906 H972 1 - - - - ZZZ 2 AB01678010 H IC D16C78BP H972 R1.1/XXXX...
  • Page 32 H972 33uH (BH01448) SL1016T 1 - - - - L771 62 DC02H000000 HOUSING CONN. SET H972 MB E821-CDT E252 EF20121 1 - - - - E821 63 DC02H000100 HOUSING CONN. SET H972 MB E011-CDT E251 EF20112 1 - - - - E011 64 DC030040300 WAFER CONN.
  • Page 33 90 MAB80013400 SCREW M3X0.5+14B-MC 4 - - - - &M01 &M02 &M03 &M04 91 MABA0002400 SCREW TPB2X3+12V-MC 5 - - - - &M05 &M06 &M07 &M08 &M09 92 X62A2488011 PCBA, POWER VA-906 H972 1 - - - - ZZZ œ 33 œ...
  • Page 34 ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------------------------------------------------------------------------------------------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----- # 446A2488011 AIS ASSY, DEF & POWER VA-906 H972 1 BB1067300T4 TRANSISTOR 2SA673AC PNP TO-92 2 - - - - Q402 Q803...
  • Page 35 =================================================================================================================== QUANTITY REQUIRED DWG.NO. 456A24 REV. 1E C NO. PART NO. DESCRIPTION SPECIFICATION --------------------------------------------- -------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ---------------------------------------------------------------------------------------------- ----- ----- ----- 33 CB022A6MHT0 CAPACITOR 2.2U 50V M A P5 1 - - - - C806 34 CB033AAMHT0 CAPACITOR 3.3U 100V M A P5 2 - - - - C779 C77E...
  • Page 36 =================================================================================================================== QUANTITY REQUIRED DWG.NO. 456A24 REV. 1E C NO. PART NO. DESCRIPTION SPECIFICATION --------------------------------------------- -------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- 69 CC2002211T9 RESISTOR 1/8W 20K +-5% 1 - - - - R827 70 CC2200211T5 RESISTOR 1/8W 220 +-5%...
  • Page 37 2 - - - - C512 C756 119 CM047E6KHT0 MONO. CAP. 470P 50V K X7R 1 - - - - C750 120 DA1H972V010 PCB H972 VA-906 REV1A 1 - - - - BMA 121 DC1100014T0 SPARK GAP TAIYOYUUDEN AG15PC-152FB-K2M 1 - - - - G501...
  • Page 38 =================================================================================================================== QUANTITY REQUIRED DWG.NO. 456A24 REV. 1E C NO. PART NO. DESCRIPTION SPECIFICATION ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- ----- K804 K813 K912 K91C K924 K928 K932 K939 K950 K951 K952 K954 K964 K971 K972 K973 K997 132 XX0900T2200 JUMP WIRE...
  • Page 39 ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- ----- # X62A2488011 PCBA, POWER VA-906 H972 1 AB002230000 TOP223Y TO-220 1 - - - - I940 2 AB006210100 TLP621F DIP-4 PHOTOCOUPLER...
  • Page 40 H971 POWER 700uH ER-35 BV00991 1 - - - - L910 44 DG1H0000100 TRANSFORMER H971 POWER ER-35 (BT01531) 1 - - - - T921 45 DG1H0000200 TRANSFORMER H972 ER-28 POWER (BT01542) 1 - - - - T940 46 DX504P022H0 FUSE 4.0A 250V S UL/CSA 1 - - - - F901...
  • Page 41 SPECIFICATION ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # X61A2488011 AIS ASSY, POWER VA-906 H972 1 BB1043100T0 TRANSISTOR KA431AZ 2 - - - - Q971 Q981 2 BB1093301T0...
  • Page 42 =================================================================================================================== QUANTITY REQUIRED DWG.NO. 456A24 REV. 1E C NO. PART NO. DESCRIPTION SPECIFICATION ----------------- ------------------------------------------------------------------ REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- 39 CC10040B1TZ RESISTOR (GRAZD) /2W 1M +-5% 1 - - - - R901 40 CC1201011T7 RESISTOR 1/2W 1.2K +-5%...
  • Page 43 DISPLAY UNIT ASSEMBLY œ 43 œ...
  • Page 44 =================================================================================================================== QUANTITY REQUIRED DWG.NO. MH972H REV. 0C C NO. PART NO. DESCRIPTION SPECIFICATION ------------------------------------------------------------------------------------ REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # MH972H01 MH972H01 TOP ASSY UR+SEMKO+CUL+C-T+TCO99 HIT 1 GA02000000H POWER CORD SET SP023X1.8MXIS14 H05VV-F GRY 1 - - - - 301 2 GA05000000H POWER CORD SET...
  • Page 45: Display Assembly

    =================================================================================================================== QUANTITY REQUIRED DWG.NO. X66A64 REV. 0B C NO. PART NO. DESCRIPTION SPECIFICATION ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # X66A6488001 MECHANICAL PACKING H971 1 FJH9712J100 BOTTOM CUSHION DJ72-K049 SP07061 1 - - - - 201 2 FJH9712K100...
  • Page 46 MH972H01 PACKING HHEE U+SEMKO+CUL+C-T+TCO99 HIT # 62003188003 PACKING CM772U-CI MH972H UR+SEMKO+CU+C-T+T99 1 EJ4H9720000 RATING NP (L) N-H972-HAL U0FGC EX TCO99 1 - - - - 2 EJ4H9720200 RATING NP (L) N-H972-HHEE U0FGC EX TCO99 - 1 - - - 3 EJ4H9720300...
  • Page 47 œ 47 œ...
  • Page 48 œ 48 œ...
  • Page 49 DIS. UNIT ASSY, HAL MH972 U+SEMKO+CUL+C-T+T99 HIT # 52261588002 DIS CM772U-CI MH972H U+SEMKO+CU+C-T+T99 1 CLA9H000000 DEGAUSSING COIL H972 CRT AROUND .45X90BZ02621J 1 1 - - - 302 2 HGTH9710000 REV LABEL H971-L001 FOR CHASSIS 1 1 - - - 303 3 EJ3H1110000 LOGO NP N-H111-CI "CORNERSTONE"...
  • Page 50 88 88 011 012 REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # X66A6588011 MECHANICAL FINAL ASSY H972 # X66A6588012 MEC PARTS MH972H FINAL ASSY 1 EEH97115100 REAR SHIELD DJ72-K053 MD05741...
  • Page 51 ------------------ ----------------------------------------------------------------- REMARKS - ---- ----------- ------------------------ ------------------------------ --- --- --- --- --- ----- ----- ----- ----- ----- ----------------------------------------------------------------------------------------- # X66A6688011 CHASSIS ASSY H972 1 EEH97120100 BOTTOM METAL DJ72 19-01-115 NQ07044 1 - - - - 201 2 EEH9712A100 MICON SHIELD METAL...
  • Page 52 Attachment A Page 1 of 5 Procedure to fix the Screen VR on FBT of CM771 1.Preparation (1) Solder tool with flat head.(Refer to Photo 1 and 2) 2.Operation (1) Chassis adjustment should be completed. (2) Attach the head of solder tool softly on the right side of Screen VR knob together with FBT body for approximately 5 seconds to melt them.
  • Page 53 Attachment A Page 2 of 5 Photo 1. Head of solder tool (Side view) Photo 2. Head of solder tool (Top view)
  • Page 54: Attachment A

    Attachment A Page 3 of 5 Photo 3. Melting right side of VR knob together with FBT body Photo 4. Melting right side of VR knob together with FBT body (Done)
  • Page 55 Attachment A Page 4 of 5 Photo 5. Melting left side of VR knob together with FBT body Photo 6. Melting left side of VR knob together with FBT body (Done)
  • Page 56 Attachment A Page 5 of 5 Photo 7. Melting top of VR knob Photo 8. Melting top of VR knob (Done)
  • Page 57                     !"#$%&'()%*+ ,-%))%          "#./ 0,1$2 ,,1.3. 4( "1.   "5#61   '70 ,-%&2(8%    09-%&2(%4'2 ,-%8'8()%%% ,-. 1:,5"; 5&"5 09-%8'8()(%% ,-5"1&1:5; 5&"5    !   "#   1' 1<1,%& (%(4 ",.1= %'%' 15, $  ,-%2% ,-%2)(%2%...

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