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Sharp 21l-Fg1l

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SERVICE MANUAL21L-FG1LCOLOUR TELEVISIONChassis No. GA621L-FG1LIn the interests of user safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts indentical to those specified should be used.S677221LFG1LMODELELECTRICAL SPECIFICATIONSChassis No. GA6CONTENTSIMPORTANT SERVICE SAFETY PRECAUTION ................................................................................................... 1-1PageLOCATION OF USERS CONTROL ...................................................................................................................... 2-1INSTALLATION AND SERVICE INSTRUCTIONS ................................................................................................. 3-1SERVICE MODE ..................................................................................................................................................... 4-1ADJUSTMENT METHOD ........................................................................................................................................ 5-1WAVEFORMS ......................................................................................................................................................... 6-1CHASSIS LAYOUT ................................................................................................................................................. 7-1BLOCK DIAGRAM .................................................................................................................................................. 8-1DESCRIPTION OF SCHEMATIC DIAGRAM .......................................................................................................... 9-1SCHEMATIC DIAGRAMS ......................................................................................................................................10-1PRINTED WIRING BOARD ASSEMBLIES ........................................................................................................... 11-1Parts Guide POWER INPUT............................AC 110-220 V, 50/60 Hz POWER RATING .....................................................85WPICTURE SIZE .............................1,239 cm2(192sq inch)CONVERGENCE ............................................. MagneticSWEEP DEFLECTION .................................. .. Magnetic FOCUS ........................................................ ElectrostaticINTERMEDIATE FREQUENCIES Picture IF Carrier Frequency ...................... 45.75 MHz Sound IF Carrier Frequency ...................... 41.25 MHz Color Sub-Carrier Frequency ......................42.17 MHz (Nominal)AUDIO POWER OUTPUT RATING... ...................... 3.0 W(RMS) x 2pcs SPEAKER SIZE ........................................................ 2 X 3.5, 2pcs VOICE COIL IMPEDANCE .................16 ohm at 400 HzANTENNA INPUT IMPEDANCE VHF/UHF ........................................75 ohm UnbalancedTUNING RANGES VHF-Channels ................................................. 2 thru 13 UHF-Channels ................................................14 thru 69 CATV Channels ............................................. 1 thru 125 (EIA, Channel Plan U.S.A.)Specifications are subject to change withoutprior notice.SHARP CORPORATIONThis document has been published to be used for aftersales service only.The contents are subject to change without notice.21L-FG1L1 1TV 21L-FG1L Service Manual 21L-FG1L Market ECHAPTER 1. IMPORTANT SERVICE SAFETY PRECAUTION[1] IMPORTANT SERVICE SAFETY PRECAUTIONIMPORTANT SERVICE SAFETY PRECAUTIONService work should be performed only by qualified service technicians who arethoroughly familiar with all safety checks and the servicing guidelines which follow:X-RADIATION AND HIGH VOLTAGE LIMITS1. Be sure all service personnel are aware of theprocedures and instructions covering X-radiation.The only potential source of X-ray in current solidstate TV receivers is the picture tube. However, thepicture tube does not emit measurable X-Rayradiation, if the high voltage is as specified in the"High Voltage Check" instructions.It is only when high voltage is excessive that X-radiation is capable of penetrating the shell of thepicture tube including the lead in the glass material.The important precaution is to keep the high voltagebelow the maximum level specified.2. It is essential that servicemen have available at alltimes an accurate high voltage meter.The calibration of this meter should be checkedperiodically.3. High voltage should always be kept at the rated valueno higher. Operation at higher voltages may causea failure of the picture tube or high voltage circuitryand;also, under certain conditions, may produceradiation in exceeding of desirable levels.4. When the high voltage regulator is operating properlythere is no possibility of an X-radiation problem.Every time a color chassis is serviced, the brightnessshould be tested while monitoring the high voltagewith a meter to be certain that the high voltage doesnot exceed the specified value and that it is regulatingcorrectly.5. Do not use a picture tube other than that specifiedor make unrecommended circuit modifications to thehigh voltage circuitry.6. When t r oubl e shoot i ng and t aki ng t estmeasurements on a receiver with excessive highvoltage, avoid being unnecessarily close to thereceiver.Do not operate the receiver longer than is necessaryto locate the cause of excessive voltage.WARNING1. For continued safety, no modification of any circuitshould be attempted.2. Disconnect AC power before servicing.3. Semiconductor heat sinks are potential shockhazards when the chassis is operating.4. The chassis in this receiver has two ground systemswhich are separated by insulating material. The non-isolated (hot) ground system is for the B+ voltageregulator circuit and the horizontal output circuit. Theisolated ground system is for the low B+ DC voltagesand the secondary circuit of the high voltagetransformer.To prevent el ectri cal shock use an i sol ati ontransformer between the line cord and powerreceptacle, when servicing this chassis.SERVICING OF HIGH VOLTAGE SYSTEMAND PICTURE TUBEWhen servicing the high voltage system,remove the static charge by connecting a10k ohmresistor in series with an insulatedwire (such as a test probe) between the pic-ture tube ground and the anode lead. (ACline cord should be disconnected from ACoutlet.)1. Picture tube in this receiver employs integralimplosion protection.2. Replace with tube of the same type number forcontinued safety.3. Do not lift picture tube by the neck.4. Handl e the pi cture tube onl y when weari ngshatterproof goggles and after discharging the highvoltage anode completely.

21L-FG1L1 2SAFETY NOTICEMany electrical and mechanical parts in televisionreceivers have special safety-related characteristics.These characteristics are often not evident from visualinspection, nor can protection afforded by them benecessarily increased by using replacement componentsrated for higher voltage, wattage, etc.Replacement parts which have these special safetycharacteristics are identified in this manual; electricalcomponents having such features are identified by " "and shaded areas in the Replacement Parts Lists andSchematic Diagrams.IMPORTANT SERVICE SAFETY PRECAUTION(Continued)1. Inspect all lead dress to make certain that leads arenot pinched or that hardware is not lodged betweenthe chassis and other metal parts in the receiver.2. Inspect all protective devices such as non-metalliccontrol knobs, insulating materials, cabinet backs,adjustment and compartment covers or shields,isolation resistor-capacity networks, mechanicalinsulators, etc.3. To be sure that no shock hazard exists, check forleakage current in the following manner.Plug the AC cord directly into a 110~220 volt ACoutlet, (Do not use an isolation transformer for thistest).Using two clip leads, connect a 1.5k ohm, 10 wattresistor paralleled by a 0.15F capacitor in serieswith all exposed metal cabinet parts and a knownearth ground, such as electrical conduit or electricalground connected to earth ground.Use an AC voltmeter having with 5000 ohm per volt,or higher, sensitivity to measure the AC voltage dropacross the resistor.BEFORE RETURNING THE RECEIVER(Fire & Shock Hazard)Before returning the receiver to the user, performthe following safety checks.Connect the resistor connection to all exposed metalparts having a return to the chassis (antenna, metalcabinet, screw heads, knobs and control shafts,escutcheon, etc.) and measure the AC voltage dropacross the resistor.AII checks must be repeated with the AC line cordplug connection reversed. (If necessary, a non-polarized adapter plug must be used only for thepurpose of completing these check.)Any current measured must not exceed 0.5 milliamp.Any measurements not within the limits outlinedabove indicate of a potential shock hazard andcorrective action must be taken before returning theinstrument to the customer.For continued protection, replacement parts must beidentical to those used in the original circuit. The use ofsubstitute replacement parts which do not have the samesafety characteristics as the factory recommendedreplacement parts shown in this service manual, maycreate shock, fire, X-radiation or other hazards.DVMAC SCALE1.5k ohm10WTO EXPOSEDMETAL PARTSCONNECT TOKNOWN EARTHGROUND21L-FG1L