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No. 0415 CM821FET CM823FET CM827ET CM828ET SERVICE MANUAL Data contained within this Service manual is subject to alteration for improvement. Les données fournies dans le présent manuel d’entretien peuvent faire l’objet CAUTION: de modifications en vue de perfectionner le produit.
FEATURES ESH or Equivalent) Connect (-) to chassis earth and (+) to the CDT anode 1. Flat screen CRT with anti-glare, dynamic focus circuit, button. (See the following connection diagram Fig. 1.) dark glass, and INVAR shadow mask give the NOTE: Turn power switch off without fail before making sharpest focus and highest contrast.
Service Manual, may create shock, fire, X-radiation, or other hazards. FIG. 2 CHECKING CIRCUIT USING JIG Productions are issued from time to time. For the latest information, always consult this Service Manual. SPECIFICATIONS CM821FET CM823FET CM827ET CM828ET Model Name Destination...
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CONTROLS Front Cover CRT Surface Power Switch Control Panel Tilt & Swivel Base FIG.3 FRONT VIEW FIG. 3 FRONT VIEW FIG. 4 CONTROL PANEL Signal Cable AC Inlet (D-Sub Mini 15-pin) D-Sub Mini 15-pin FIG. 5 REAR VIEW...
SIGNAL TIMING CHART VESA VESA VESA Signal 640×400 800×600 1024×768 1280×1024 (70Hz) (85Hz) (85Hz) (85Hz) CM821F CM821FET 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...
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VESA VESA Signal Adjustment 1600×1200 1600×1200 640×480 signal (90Hz) (75Hz) (60Hz) CM821F CM821FET 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...
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 (C901 ~C905,C907) and rectifier (D901~D904). Rectifier circuits adapt to full-wave method.
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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 + 6.2V Manual Degauss + 12V Chopper Reg. Control Heater On/Off On/Off control Standby power supply...
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.
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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.
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 27.5 kV is obtained by the step-up windings of the flyback transformer to drive the CRT anode.
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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, synchronised by the V sync pulse. V sync is input to the V oscillator circuit, I701, generating the vertical saw tooth wave.
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).
6. Power Save Function The DJ82 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.
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, I940, D901, D902, D903, D904, Abnormal Abnormal Check F901 Replace F901 C901, C902, C903, C904, C905, C907, C910, C920...
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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 DJ82 Video V.SYNC is Board or Main Board) normal...
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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 DJ82 Main Board) Normal (12V) Abnormal Abnormal Check the Check Abnormal Check the...
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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-pcb to disable Main power supply voltage. (3) Place resister 3.9kΩ...
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.
When the value shown below can not low: Change the R827 to R82D. 3.2 White balance adjustment (Color 2) (1) Receive a signal of 112C with a 100×100 mm window pattern. (2) Set Brightness Control to the center (7Fh) and C-Cont to the minimum (00h). (3) Adjust the light output to 80 cd/m (24.6ft-L) at the center of screen by adjusting Sub Contrast Control.
4 Focus adjustment (1) Receive signal 94A with a full screen “E” characters. (2) Set user Contrast control to its maximum. (3) Set user Brightness control so that the back ground raster is just diminished. (4) Adjust S-Focus control on the FBT so that focus at the middle points between the center of the screen to its best.
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DJ72 BLOCK DIAGRAM 15P-DSUB R . G . B . G A I N C O N T R O L VIDEO INPUT 1 OUT PUT CONTROL C L P H. SYNC V. SYNC BUFFER Sync on G Sep. DDC5V CONT C-CONT SYNC S-BKG...
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Attachment A Page 1 of 5 Procedure to fix the Screen VR on FBT of CM823 Add Copper tape form of 2 input board Add a Grounding Spring for EMI solution . Operation (1) Chassis adjustment should be completed and prepare bond glue (2) Attach the head of glue to bond softly on the right side of Screen VR knob (3) Attach the head of glue to bond softly on the left side of Screen VR knob (4) Attach the head of glue to bond softly on the top of Screen VR knob (Refer to photo 1 )
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Photo 4. The grounding spring fix on the Video heat sink MTL and screw it with a tapping screw .
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Photo 5. 1. The 2 GND wires go through a core. (URITE F5B RH 14x15x9) P/N: DC150009800 2. Add a copper finger from CRT cover to the screw of CRT neck. P/N: EEF1154A100.