Adcom-GFA5500-pwr-sm维修电路原理图.pdf

SERVICE MANUAL2 CHANNELPOWER AMPLIFIERGFA-5500TABLE OF CONTENTSIntroduction . . . . . . . . . . . . . . . . 1Test Procedures . . . . . . . . . . . . . 1Parts List . . . . . . . . . . . . . . . . . . 2Specifications . . . . . . . . . . . . . . . 5Schematic . . . . . . . . . . . . . . . . . 910 Timber LaneMarlboro, NJ 07746USATel: 732-683-2356Fax: 732-683-9790Web: http:/RadioFans.CN 收音机爱 好者资料库1INTRODUCTIONThis service manual is intended to assist trained and qualified technical personnel in verifying theperformance of, adjusting, and repairing the ADCOM GFA-5500 amplifier. The procedures described here arenot intended for persons unfamiliar with the appropriate safety and test procedures.TEST PROCEDURES All tests are performed with a 115V, low-distortion (less than 2% THD), AC-power source, 8-ohmresistive load (except slew rate), and a signal source of not more than 600 ohms. An 80kHz low-pass filter is employed during THD distortion measurements. Signal-to-noise measurements are “A” weighted. Damping factor is measured by comparing the 1 watt output voltage with and without an 8 ohm load. Slew rate is measured with an inductive load, and is derived with a dual-time-based oscilloscope readingthe slope of a full power 5kHz square wave. DO NOT OPERATE THE AMPLIFIER AT FULL-POWERSINE WAVE ABOVE 22kHz OR FULL-POWER SQUARE WAVE ABOVE 5kHz.CORRECT BIAS ADJUSTMENT IS CRITICAL TO THE PERFORMANCE OF THIS AMPLIFIER.MAXIMUM OUTPUT POWER, MINIMUM THD AND HEAT DISSIPATION ARE AFFECTED BY THE BIASSETTING AND MUST BE CORRECT TO MAINTAIN THE SONIC QUALITY AND LONGEVITY OF THEAMPLIFIER.BIAS ALIGNMENTPrior to performing BIAS ALIGNMENT turn unit on and allow to idle for approximately 5 MINUTES beforeattempting adjustments.1. Connect millivoltmeter across emitter resistor R52 for left channel (R51 for right channel)2. Adjust bias pot P2 until meter reads 50mV +/- 5mVDC OFFSET ADJUSTMENT1. Connect millivoltmeter across speaker output2. Adjust DC offset pot P1 until meter reads 0mV +/- 10mV WARNING THERE ARE POTENTIALLY LETHAL VOLTAGES WITHIN THE GFA-5500 AMPLIFIER WHICH WILL BEACCESSIBLE ONCE ITS TOP COVER IS REMOVED. DO NOT ATTEMPT FAMILIARIZATION,INSPECTION, OR ANY PROCEDURE WHATSOEVER UNLESS YOU HAVE DISCONNECTED THE GFA-5500 FROM THE WALL AC OUTLET OR OTHER SOURCE OF AC POWER AND THE POWER-SUPPLYCAPACITORS ARE COMPLETELY DISCHARGED. THESE INSTRUCTIONS ARE PROVIDED FOR USEONLY BY COMPETENT TECHNICAL PERSONNEL. DO NOT UNDERTAKE ANY SERVICEPROCEDURES IN THE GFA-5500 UNLESS YOU ARE TECHNICALLY QUALIFIED TO DO SO.IMPORTANTBEFORE PROCEEDING WITH ADJUSTMENTS, MAKE SURE AMPLIFIER IS AT ROOMTEMPERATURE.RadioFans.CN 收音机爱 好者资料库2GFA-5500 SERVICE PARTS LISTAMPLIFIER MODULE PCBSCHEMATICADCOM PART NUMBERDESCRIPTIONLOCATIONC0112001535CAPACITOR MICA390pF 100VC0212001080CAPACITOR MYLAR2.2uF 100VC0312005280CAPACITOR ELEC47Uf 50VC0412001085CAPACITOR MYLAR0.22uF 100VC0512001480CAPACITOR SILVER MICA15pF 500VC0612001470CAPACITOR SILVER MICA20pF 500VC0712005325CAPACITOR ELEC4.7uF 50VC0912005380CAPACITOR ELEC47uF 25VLED116001204THERMAL LEDLTL1204 (RED)LED216001254DISTORTION LEDLTL1254 (YELLOW)P0135001550DC OFFSET POT5K MULTI TURNP0235001550BIAS POT5K MULTI TURNQ01,Q0233002100TRANSISTORIRFD210Q03,Q0433000092TRANSISTORMPSA92Q0533000092TRANSISTORMPSA92Q0633009210TRANSISTORIRFD9210Q0733009610TRANSISTORIRF9610Q0833002100TRANSISTORIRFD210Q0933000042TRANSISTORMPSA42Q10,Q1133000610TRANSISTORIRF610Q1233000042TRANSISTORMPSA42Q1333000042TRANSISTORMPSA42Q1433000092TRANSISTORMPSA92Q1533002400TRANSISTORIRFP240Q1633000924TRANSISTORIRFP9240Q1733002400TRANSISTORIRFP240Q1833000924TRANSISTORIRFP9240Q1933002400TRANSISTORIRFP240Q2033000924TRANSISTORIRFP9240Q2133002400TRANSISTORIRFP240Q2233000924TRANSISTORIRFP9240Q2333002400TRANSISTORIRFP240Q2433000924TRANSISTORIRFP9240R0127001565RESISTOR ROED221R (1/4W 1%)R0227002480RESISTOR ROED1.82K (1/4W 1%)R0327002365RESISTOR ROED49.9K (1/4W 1%)R0427002480RESISTOR ROED1.82K (1/4W 1%)R0527002030RESISTOR ROED10K (1/4W 1%)R0627002280RESISTOR ROED15K (1/4W 1%)R0727002170RESISTOR ROED475R (1/4W 1%)R0827001565RESISTOR ROED221R (1/4W 1%)R0927001565RESISTOR ROED221R (1/4W 1%)R1027002010RESISTOR ROED100R (1/4W 1%)R1127002030RESISTOR ROED10K (1/4W 1%)R1227002365RESISTOR ROED49.9K (1/4W 1%)R1327002240RESISTOR ROED7.5K (1/4W 1%)R1427002025RESISTOR ROED1.5K (1/4W 1%)SCHEMATICADCOM PART NUMBERDESCRIPTIONRadioFans.CN 收音机爱 好者资料库3LOCATIONR1527002030RESISTOR ROED10K (1/4W 1%)R1627002500RESISTOR ROED33.2K (1/4W 1%)R16A27002500RESISTOR ROED33.2K (1/4W 1%)R1727001565RESISTOR ROED221R (1/4W 1%)R1827001565RESISTOR ROED221R (1/4W 1%)R1927001515RESISTOR ROED4.75R (1/4W 1%)R2027002010RESISTOR ROED100R (1/4W 1%)R2127002030RESISTOR ROED10K (1/4W 1%)R2227002200RESISTOR ROED4.99K (1/4W 1%)R2327001530RESISTOR ROED2.74K (1/4W 1%)R2427003035RESISTOR5.1K (1W 5% MOD)R25,R2627002410RESISTOR ROED4.75K (1/4W 1%)R27,R2827003390RESISTOR220R (1/2W 5% MOF)R29,R3027003090RESISTOR47R (1/2W 5% MOF)R3227002365RESISTOR ROED49.9K (1/4W 1%)R33-R4227003390RESISTOR220R (1/2W 5% MOF)R43-R5227006045RESISTOR0.68R (5W 5% W.W.)R5327002030RESISTOR ROED10K (1/4W 1%)TB10132006000THERMAL BREAKERZ01-Z0816000082DIODEZENER 8.2V (1/2W)POWER SUPPLY PCBSCHEMATICADCOM PART NUMBERDESCRIPTIONLOCATIONBR1,BR216003506BRIDGE RECTIFIER600V 35A DB3506/TC112001235CAPACITOR MYLAR0.1uF 250VC10,C1112005525CAPACITOR ELEC18,000uF 100VC12,C1312001235CAPACITOR MYLAR0.1uF 250VC1412005525CAPACITOR ELEC18,000uF 100VC1512001235CAPACITOR MYLAR0.1uF 250VC16-C1912005265CAPACITOR ELEC1000uF 100VC2012001235CAPACITOR MYLAR0.1uF 250VC2-C512005265CAPACITOR ELEC1000uF 100VC612001235CAPACITOR MYLAR0.1uF 250VC712005525CAPACITOR ELEC18,000uF 100VC8,C912001235CAPACITOR MYLAR0.1uF 250VD1-D816004004DIODE1N4004F1-F419000800RAIL FUSE8A 250V 3AGR0127003365RESISTOR22R (2W 5% MOF)R02,R0327003355RESISTOR15K (2W 5% MOF)R0427003365RESISTOR22R (2W 5% MOF)R05,R0627003300RESISTOR10R (2W 5% MOF)R07-R1027003280RESISTOR8.2K (2W 5% MOF)R11,R1227003300RESISTOR10R (2W 5% MOF)R1327003365RESISTOR22R (2W 5% MOF)R14,R1527003355RESISTOR15K (2W 5% MOF)R1627003365RESISTOR22R (2W 5% MOF)R1727003335RESISTOR6.8K (1W 5% MOF)TH1,TH231005500THERMISTORCL40OUTPUT PCBRadioFans.CN 收音机爱 好者资料库4SCHEMATICADCOM PART NUMBERDESCRIPTIONLOCATION30005800BINDING POSTRED/BLACKC812001235CAPACITOR MYLAR0.1uF 250VR3127001000RESISTOR4.7R (2W 5% MOF)OTHERSSCHEMATICADCOM PART NUMBERDESCRIPTIONLOCATIONC2112001510SPARK KILLER0.01uF 400VF519001200MAIN FUSE12A 250VTH333005800THERMISTORCL10113005500FRONT PANEL13005504HEATSINK LEFT13005505HEATSINK RIGHT37001325POWER SWITCH22001170RCA INPUT JACK13005501TOP COVER13005805FOOTRadioFans.CN 收音机爱 好者资料库5 a GFA-5500 Voltage ConversionThe GFA-5500 amplifier is produced in both a 120VAC only version and a multivoltage (120VAC or 230VACconvertible) version. The version can usually be distinguished by external inspection. The 120VAC onlyversion has a fixed AC line cord. The convertible version has a detachable line cord. Internally, their are twodifferences. The toroid transformer in the convertible version has 2 primaries; the first primary has a blackand brown lead, the second primary has a black and brown lead with white stripe. The toroid transformer inthe 120VAC only version has only the brown and black lead (1 primary winding). Additionally, theconnecting block mounted next to the power switch is different in both versions. In the multivoltage unit,this connecting block has 6 pair of mounting leads (as is shown in the figures below). In the 120VAC onlyversion, the connecting block has only 4 pairs of mounts.The conversion procedure for the multivoltage GFA-5500 unit is listed below.Conversion of Multivoltage Units120V to 230V1. Unplug the amplifier and remove the top cover.2. Locate the connecting block mounted next to the power switch.3. Move the transformer leads so they are configured as shown in figure 1.4. Change the rear panel AC fuse from 12A to 6A, AGC. Place a sticker on the rear panel at the fuse holderto show the new value fuse (6A) and new value operating voltage (230VAC).5. Test the unit with a 230VAC source.Figure 1: Transformer lead configuration for 230VAC operation (multivoltage units)KC103PKCCCL-10White(from AC fuse)Brown(to xformer)Brown/White(to xformer)Black(to xformer)Black/White(to xformer)RadioFans.CN 收音机爱 好者资料库6230V to 120V1. Unplug the amplifier and remove the top cover.2. Locate the connecting block mounted next to the power switch.3. Move the transformer leads so they are configured as shown in figure 2.4. Change the rear panel AC fuse from 6A to 12A, AGC. Place a sticker on the rear panel at the fuse holderto show the new value fuse (12A) and new value operating voltage (120VAC).5. Test the unit with a 120VAC source.Figure 2: Transformer lead configuration for 120VAC operation (multivoltage units)KC103PKCCCL-10White(from AC fuse)Brown(to xformer)Brown/White(to xformer)Black(to xformer)Black/White(to xformer)RadioFans.CN 收音机爱 好者资料库7 GFA-5500 SPECIFICATIONSPower Rating (To FTC Requirements)200 watts continuous average power per channel into 8 ohms at any frequency between 20Hz to 20kHzwith all channels driven at less than 0.18% THD350 watts continuous average power per channel into 4 ohms at any frequency between 20Hz to 20kHzwith all channels driven at less than 0.18% THDIM Distortion (SMPTE)1 watt to 200 watts into 8 ohms. 0.05%1 watt to 350 watts into 4 ohms. 0.05%IM Distortion (CCIF, Any Combination from 4kHz to 20kHz)200 watts into 8 ohms. 0.04%350 watts into 4 ohms. 0.04%THD + Noise at 200 watts into 8 ohms (Typical)20Hz. 0.018%1kHz. 0.02%10kHz. 0.07%20kHz. 0.13%THD + Noise at 350 watts into 4 ohms (Typical)20Hz. 0.018%1kHz. 0.02%10kHz. 0.08%20kHz. 0.16%Frequency Response 1 Watt into 8 ohms (10Hz to 20kHz). +0, -0.25dBPower Bandwidth (-3dB) . 3Hz to 130kHzDynamic Headroom into 4 ohms. 1.7 dBSignal to Noise Ratio, “A” Weighted (200 watts into 8 ohms). 100dBGain. 29dBInput Sensitivityfor 1 Watt. 0.1 voltsfor 200 Watts. 1.4 voltsInput Impedance. 49.9kDamping Factor (20Hz to 20kHz). 700Rise Time (5kHz, 90V, peak-to-peak square wave, 20% to 80%). 1.5SPower Consumption (Continuous, All Channels Driven)Quiescent. 199VAMaximum . 855VA80 watts into 8 ohms. 1440VA125 watts into 4 ohms. 720VAPower (Available in 230VAC on special order). 115VAC - 50/60HzChassis Dimensions . 7” (178mm) x 17” (432mm) x 13 3/4” (349mm)Maximum Dimensions. 7 1/4” (184mm) x 17” (432mm) x 14 3/4” (375mm)Weight. 44 lb. (25.9 kg)Weight, Packed. 50 lb. (28.6 kg)RadioFans.CN 收音机爱 好者资料库