Hitachi CM801U Service Manual - Page 2

FEATURES 1. Flat screen CRT with anti-glare, dynamic focus circuit, dark glass, and INVAR shadow mask give the sharpest focus and highest contrast. 2. Automatic scanning and automatic adjustment to conform with a wide range of scanning frequencies and user requirements. 3. Signal input allows 13W3 Type D-Sub or D-Sub Min 15pin cable. 4. Power Save Mode automatically puts the monitor into a standby mode (power consumption less than 30W) when the H.sync. signal is not detected, and a power - off mode (less than 5W) when the V.sync, signal is not detected. Normal mode is restored immediately when the H. sync. signal and the V.sync signal are detected. This feature prolongs monitor life and reduces energy consumption by up to about 75 %. SAFETY PRECAUTIONS NOTICE: Comply with all cations and safety related notes located on or inside the cabinet and on the chassis or picture tube. The following precautions must be observed. 1. Do not install, remove, or handle the picture tube in any manner unless shatterproof goggles are worn. People not so equipped should be kept away while picture tubes are handled. 2. When replacing a chassis in the monitor, all the protective devices must be put back in place, such as, barriers, nonmetallic knobs, adjustment and compartment shields, and isolation resistor-capacitor, etc. 3. When service is required, observe the original lead dress. Extra precaution should be taken to assure correct lead dress in the high voltage circuitry area. 4 Always use the manufacturer's replacement components. Especially critical components as indicated on the circuit diagram should not be replaced by other manufacturer's. Furthermore where a short circuit has occurred, replace those components that indicate evidence of overheating. 5. Before returning a serviced monitor to the customer, the service personnel must throughly test unit to be certain that it is completely safe to operate without danger of electrical shock, and be sure that no protective device built into the monitor by the manufacturer has become defective, or inadvertently defeated during servicing. Therefore, the following checks should be performed for continued protection of the customer and service technician. 6. In the case of the micro prossesor unit, shop adjustment is necessary after exchange of the micro prossesor unit. High Voltage This monitor is provided with a high voltage hold down circuit for clearly indicating that voltage has increased in excess of a predetermined value. Comply with notes described in this Service Manual regarding this hold down circuit when servicing, so that this hold down circuit may function correctly. Service Warning With minimum Brightness and Contrast the operating high voltage in this display is lower than 30 kV. If any component having influence on the high voltage is replaced, confirm that the high voltage with minimum Brightness and Contrast id lower than 30 kV. To measure high voltage use a high impedance highvaltage meter. (SENSITIVE RESEARCH Model: ESH or Equivalent) Connect (-) to chassis earth and (+) to the CDT anode button. (See the following connection diagram Fig. 1.) NOTE: Turn power switch off without fail before making the connection to the Anode button CDT ANODE (+) (-) HIGH IMPEDANCE H.V. METER SENSITIVE RESEARCH Model: ESH or equivalent. CHASSIS GROUND Fig. 1 X-radiation TUBE: The source of X-radiation in this monitor is the picture tube. The tube utilized in this chassis is specially constructed to limit X-radiation emissions. For continued X-radiation protection, the replacement tube must be the same type as the original, manufacturer approved type. When troubleshooting and making test measurements in a monitor with a problem of excessive high voltage, avoid being unnecessarily close to the picture tube and the high voltage components. Do not operate the chassis longer than is necessary to locate the cause of excessive voltage. CHECK OF HIGH VOLTAGE HOLD DOWN CIRCUIT Checking of the high Voltage hold down circuit operation. 1. Turn the switch of the unit ON, and set the Brightness and Contrast controls to max. 2. Turn the switch of the unit OFF. 3. Connect a DC Voltmeter and an adjustment jig as shown in Fig. 2. 4. Set the adjustment VR to fully counterclockwise. 5. Turn the switch of the unit ON and gradually rotate the adjustment VR clockwise. 6. Check that a reading of DC voltage-meter is less-than 0.6 ± 0.1 V when picture disappears. 7. Turn the switch of the unit OFF immediately after checking that the picture disappears. 8. Remove the adjusting jig and the DC voltmeter. NOTE: Reading of 0.6 V is approximately equivalent to 30 kV of CDT Anode High Voltage. PRODUCT SAFETY NOTICE Many electrical mechanical parts in the color monitor units have special safety related characteristics. These are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in this Service Manual. Electrical components having such features are identified by markin with© on the schematics and on the parts list in this Service Manual. The use of a substitute replacement component which does not have the same safety characteristics as the manufacturer recommended replacement one, shown in the parts list in this Service Manual, may create shock, fire, X-radiation, or other hazards. Productions are issued from time to time. For the latest information, always consult this Service Manual. DC Volt meter (10 V range) Clockwise Variable Resister 100 kit-B (1/2W) To Chassis Ground 0-a=3 -0 O79Z 0-3=0 R792 DEF BOARD ASS'Y Resister 120 kit (1/2W) Fig. 2 Checking Circuit using jig SPECIFICATIONS Model Name CM803U CM802U CM802E CM801U CM800U Destination North America North America Europe North America North America Rated Volyage AC 100-120 / 200-240 V, Automatically select. Provided with Power Circuit. Power Consumption 130 W nominal Color Display Tube (CDT) 21inch inches diagonal, 0.26 mm pitch Invar shadow mask, Black matrix, Anti-Reflection coat, Short persistence phosphors. Rated Horizontal Frequency Vertical Resolution Horizontal 31 - 115 kHz 31 - 102 kHz 50- 160 Hz Up to 1600 31 - 95 kHz 31 - 89 kHz Up to 1280 Vertical Signal Inputs Up to 1200 Red, Green and Blue analog video H/V separate, H/V composite or Sync .on Green sync. Up to 1024 User Controls Power Switch Degauss Store Contrast Brightness Horizontal Position, Size Vertical Position, Size Right Side Pincushion Right Trapezoid Side Pincushion Trapezoid Parallelogram Red,Green,Blue intensity Color Select Rotation H Moire Reduction V Moire Reduction Environmental Condition Temperature Humidity Operation .• 5°C to 35°C .• 10% to 80% Storage -20°C to 60°C 10% to 90°C Dimensions 488 (W) x 474 (H) X 534 (D) mm Including Tilt & Swivel base. Weight 33 kg