Adcom-GFA5500-pwr-sm维修电路原理图.pdf

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1、SERVICE MANUAL 2 CHANNEL POWER AMPLIFIER GFA-5500 TABLE OF CONTENTS Introduction . . . . . . . . . . . . . . . . 1 Test Procedures . . . . . . . . . . . . . 1 Parts List . . . . . . . . . . . . . . . . . . 2 Specifications . . . . . . . . . . . . . . . 5 Schematic . . . . . . . . . . . . . . . . . 9

2、 10 Timber Lane Marlboro, NJ 07746 USA Tel: 732-683-2356 Fax: 732-683-9790 Web: RadioFans.CN 收音机爱 好者资料库 1 INTRODUCTION This service manual is intended to assist trained and qualified technical personnel in verifying the performance of, adjusting, and repairing the ADCOM GFA-5500 amplifier. The proce

3、dures described here are not 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-ohm resistive load (except slew rate), and a signal source of not more than 600 ohm

4、s. 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-b

5、ased oscilloscope reading the slope of a full power 5kHz square wave. DO NOT OPERATE THE AMPLIFIER AT FULL-POWER SINE 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 DISSIPATIO

6、N ARE AFFECTED BY THE BIAS SETTING AND MUST BE CORRECT TO MAINTAIN THE SONIC QUALITY AND LONGEVITY OF THE AMPLIFIER. BIAS ALIGNMENT Prior to performing BIAS ALIGNMENT turn unit on and allow to idle for approximately 5 MINUTES before attempting adjustments. 1. Connect millivoltmeter across emitter re

7、sistor R52 for left channel (R51 for right channel) 2. Adjust bias pot P2 until meter reads 50mV +/- 5mV DC OFFSET ADJUSTMENT 1. Connect millivoltmeter across speaker output 2. Adjust DC offset pot P1 until meter reads 0mV +/- 10mV WARNING THERE ARE POTENTIALLY LETHAL VOLTAGES WITHIN THE GFA-5500 AM

8、PLIFIER WHICH WILL BE ACCESSIBLE 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-SUPPLY CAPACITORS ARE COMPLETELY DISCHARGED. THESE INST

9、RUCTIONS ARE PROVIDED FOR USE ONLY BY COMPETENT TECHNICAL PERSONNEL. DO NOT UNDERTAKE ANY SERVICE PROCEDURES IN THE GFA-5500 UNLESS YOU ARE TECHNICALLY QUALIFIED TO DO SO. IMPORTANT BEFORE PROCEEDING WITH ADJUSTMENTS, MAKE SURE AMPLIFIER IS AT ROOM TEMPERATURE. RadioFans.CN 收音机爱 好者资料库 2 GFA-5500 SER

10、VICE PARTS LIST AMPLIFIER MODULE PCB SCHEMATICADCOM PART NUMBERDESCRIPTION LOCATION C0112001535CAPACITOR MICA390pF 100V C0212001080CAPACITOR MYLAR2.2uF 100V C0312005280CAPACITOR ELEC47Uf 50V C0412001085CAPACITOR MYLAR0.22uF 100V C0512001480CAPACITOR SILVER MICA15pF 500V C0612001470CAPACITOR SILVER M

11、ICA20pF 500V C0712005325CAPACITOR ELEC4.7uF 50V C0912005380CAPACITOR ELEC47uF 25V LED116001204THERMAL LEDLTL1204 (RED) LED216001254DISTORTION LEDLTL1254 (YELLOW) P0135001550DC OFFSET POT5K MULTI TURN P0235001550BIAS POT5K MULTI TURN Q01,Q0233002100TRANSISTORIRFD210 Q03,Q0433000092TRANSISTORMPSA92 Q0

12、533000092TRANSISTORMPSA92 Q0633009210TRANSISTORIRFD9210 Q0733009610TRANSISTORIRF9610 Q0833002100TRANSISTORIRFD210 Q0933000042TRANSISTORMPSA42 Q10,Q1133000610TRANSISTORIRF610 Q1233000042TRANSISTORMPSA42 Q1333000042TRANSISTORMPSA42 Q1433000092TRANSISTORMPSA92 Q1533002400TRANSISTORIRFP240 Q1633000924TR

13、ANSISTORIRFP9240 Q1733002400TRANSISTORIRFP240 Q1833000924TRANSISTORIRFP9240 Q1933002400TRANSISTORIRFP240 Q2033000924TRANSISTORIRFP9240 Q2133002400TRANSISTORIRFP240 Q2233000924TRANSISTORIRFP9240 Q2333002400TRANSISTORIRFP240 Q2433000924TRANSISTORIRFP9240 R0127001565RESISTOR ROED221R (1/4W 1%) R0227002

14、480RESISTOR 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

15、 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 NUMBERDESCRIPTION 3 LOCATION R1527002030RESISTOR ROED10K (1/4W 1%) R1627002500RE

16、SISTOR 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

17、%) 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-R5227006

18、045RESISTOR0.68R (5W 5% W.W.) R5327002030RESISTOR ROED10K (1/4W 1%) TB10132006000THERMAL BREAKER Z01-Z0816000082DIODEZENER 8.2V (1/2W) POWER SUPPLY PCB SCHEMATICADCOM PART NUMBERDESCRIPTION LOCATION BR1,BR216003506BRIDGE RECTIFIER600V 35A DB3506/T C112001235CAPACITOR MYLAR0.1uF 250V C10,C1112005525C

19、APACITOR ELEC18,000uF 100V C12,C1312001235CAPACITOR MYLAR0.1uF 250V C1412005525CAPACITOR ELEC18,000uF 100V C1512001235CAPACITOR MYLAR0.1uF 250V C16-C1912005265CAPACITOR ELEC1000uF 100V C2012001235CAPACITOR MYLAR0.1uF 250V C2-C512005265CAPACITOR ELEC1000uF 100V C612001235CAPACITOR MYLAR0.1uF 250V C71

20、2005525CAPACITOR ELEC18,000uF 100V C8,C912001235CAPACITOR MYLAR0.1uF 250V D1-D816004004DIODE1N4004 F1-F419000800RAIL FUSE8A 250V 3AG R0127003365RESISTOR22R (2W 5% MOF) R02,R0327003355RESISTOR15K (2W 5% MOF) R0427003365RESISTOR22R (2W 5% MOF) R05,R0627003300RESISTOR10R (2W 5% MOF) R07-R1027003280RESI

21、STOR8.2K (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,TH231005500THERMISTORCL40 OUTPUT PCB 4 SCHEMATICADCOM PART NUMBERDESCRIPTION LOCATION 30005

22、800BINDING POSTRED/BLACK C812001235CAPACITOR MYLAR0.1uF 250V R3127001000RESISTOR4.7R (2W 5% MOF) OTHERS SCHEMATICADCOM PART NUMBERDESCRIPTION LOCATION C2112001510SPARK KILLER0.01uF 400V F519001200MAIN FUSE12A 250V TH333005800THERMISTORCL101 13005500FRONT PANEL 13005504HEATSINK LEFT 13005505HEATSINK

23、RIGHT 37001325POWER SWITCH 22001170RCA INPUT JACK 13005501TOP COVER 13005805FOOT 5 a GFA-5500 Voltage Conversion The GFA-5500 amplifier is produced in both a 120VAC only version and a multivoltage (120VAC or 230VAC convertible) version. The version can usually be distinguished by external inspection

24、. The 120VAC only version has a fixed AC line cord. The convertible version has a detachable line cord. Internally, their are two differences. The toroid transformer in the convertible version has 2 primaries; the first primary has a black and brown lead, the second primary has a black and brown lea

25、d with white stripe. The toroid transformer in the 120VAC only version has only the brown and black lead (1 primary winding). Additionally, the connecting block mounted next to the power switch is different in both versions. In the multivoltage unit, this connecting block has 6 pair of mounting lead

26、s (as is shown in the figures below). In the 120VAC only version, the connecting block has only 4 pairs of mounts. The conversion procedure for the multivoltage GFA-5500 unit is listed below. Conversion of Multivoltage Units 120V to 230V 1. Unplug the amplifier and remove the top cover. 2. Locate th

27、e 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 holder to show the new value fuse (6A) and new value operating voltage (

28、230VAC). 5. Test the unit with a 230VAC source. Figure 1: Transformer lead configuration for 230VAC operation (multivoltage units) KC103P KCC CL-10 White (from AC fuse) Brown (to xformer) Brown/White (to xformer) Black (to xformer) Black/White (to xformer) 6 230V to 120V 1. Unplug the amplifier and

29、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 holder to show the new value fuse (12A

30、) and new value operating voltage (120VAC). 5. Test the unit with a 120VAC source. Figure 2: Transformer lead configuration for 120VAC operation (multivoltage units) KC103P KCC CL-10 White (from AC fuse) Brown (to xformer) Brown/White (to xformer) Black (to xformer) Black/White (to xformer) 7 GFA-55

31、00 SPECIFICATIONS Power Rating (To FTC Requirements) 200 watts continuous average power per channel into 8 ohms at any frequency between 20Hz to 20kHz with all channels driven at less than 0.18% THD 350 watts continuous average power per channel into 4 ohms at any frequency between 20Hz to 20kHz wit

32、h all channels driven at less than 0.18% THD IM 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 (Ty

33、pical) 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, -0.25dB Power Bandwidth (-3dB) . 3Hz to 130kHz Dynamic Headroom into 4 ohms. 1.7 dB S

34、ignal to Noise Ratio, “A” Weighted (200 watts into 8 ohms). 100dB Gain. 29dB Input Sensitivity for 1 Watt. 0.1 volts for 200 Watts. 1.4 volts Input Impedance. 49.9k Damping Factor (20Hz to 20kHz). 700 Rise Time (5kHz, 90V, peak-to-peak square wave, 20% to 80%). 1.5S Power Consumption (Continuous, All Channels Driven) Quiescent. 199VA Maximum . 855VA 80 watts into 8 ohms. 1440VA 125 watts into 4 ohms. 720VA Power (Available in 230VAC on special order). 115VAC - 50/60Hz Chassis Dimensions . 7” (178mm) x 17” (432mm) x 13 3/4” (349mm) Maximum Dimensions.