Sansui AU 517 AU 717 Service Manual
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Extracted text from Sansui AU 517 AU 717 Service Manual (Ocr-read)
Page 1
AU- 517/717 1. SPCIFICA TlaNS AU-717 Power output Min. RMS, both channels driven, from 20 to 20 000 Hz, with no more than 0.025% total harmonic distortion 85 watts per channel into 8. ohms Load impedance. . . . . . . . . 8 ohms Power bandwidth. . . . . . . . . . . . . 20 to 20 000 Hz at or below rated min. RMS power output and total harmonic distortion Total harmonic distortion (POWER AMP IN) ..................... less than 0.025% at or below rated min. RMS power output Intermodulation distortion (70 Hz: 7 kHz = 4:1 SMPTE method) '...........,.... lessthanO.025% Frequency response (at 1watt) (POWER AMP IN) ..................,.. Oto200OOOHz+OdB-3dB RIAA curve daviation (PHONO) . . . . +0.2 dB -2 dB (20 to 20000 Hz) approximately 60 at 8 ohms load Damping factor. . . . . . . . . . Input sensitivity and impedance (1 kHz, for rated power output) PHONO " " 2. 5mV/47kilohms (Max. input capability; 350 mV at 1 kHz , less than 0.01 % total harmonic distortion) AUX, TAPE. . . . . . . . . . . . .. 150mV/47 kilohms Output level (1 ,000 Hz) TAPEREC(pinjack) " 150mV/47kilohms PREOUT............... 1V/47kilohms Channel separation (1 kHz , at rated power output) PHONO " betterthan60dB AUX.................. betterthan65dB Hum and noise (short-circuit, A-network) PHONO .......... 78dB AUX.............. 100dB Controls BASS. . . . . . . . . . Tone selector TREBLE ........... Toneselector........... SUBSONIC FILTER......... HIGHFILTER............ MUTING. . . . . . . . . . . . . . . LOUDNESS (-30dB) .,.:!:10dB (50 Hz) 200400 Hz :!:10dB (15kHz) , 6 kHz 3dB(16Hz), 6dB/oct 3dB (10kHz),6dB/oct 20dB 9dB at 50Hz 7dBat10kHz Power requirements Powervoltage............. 100 , 120220 240V (50/60Hzl 120V (Usable 110 - 130V) 60 Hz (for U.A. & Canada only) Power consumption Maximum consumption. . . . . . . Rated consumption. . . Dimentions................ Waight . . . . . . . . . . . . . . . . . . . 735 watts 425 watts 500 VA 430mm (16- 15/16") W 168 mm (6-5/8") H 389mm (15-3/8") D 8kg (39.2lbs) net 19.8 kg (43.7 Ibs) packed2. BLOCK DIAGRAM r----____n :r:t: I UUI , 'I --' a: I -"' """ ~~,, . , "-"-, 0.. I '" I "" :~ , ~ , ~ , 0.. I Ln_____-0 ~ ;;'1 ~ 7'" , I ~ ~ ~ t --------_:_---------+ _ :i!!:i!!, - $; ~'"" ~ ';; ~~: , , , "- "- ,----.,. n_____------ _n_______n__-,'j ,- - - - - -- ';", "'I ":"1 0.. ""I :: I :51 ,21 L______---- --- -----,,------- IIA JlI'- Ii;;; II, JI'" I:~ I:~ "(0 "'" d ..:.. - - - - -- --- JL______-n__----_n---------- ttJ~ r--------- ------------------------- -- - .. ~: 1'-' "'I ..:..' u 0.. I ~ "" I "" ~I "gl =1 ~I L______- - ------------- -- - -- - -- -----_ ~r---- (0 -(0 ------------- "C0 -(0"-- c0~--- ~: g~ &ii&ii .:.: i'i~ ~ "" L__- -- - -- --- ---- --~ -~--~--_!_--_
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AU- 517/717 3. ADVANTAGE AND OPERATION OF POWER AMPLIFIER CIRCUITRY SECTION DOl ZDOI FETOl" ...'-' ZDO2 1. Advantage OThere is neccessity not to decrease the phase response till DC range in order to increase the music signal response of extremely low frequency range. Therefore, this amplifier is employing no capacitors except ones for phase compensa- tion, and has an almost perfect transient characteristics. 0 The first stage FET (2SK9?) is a dual FET of even characteris- tics and has a large Gm and no-leakage current at normal temparature. To avoid the influence by temperature drift , such as center voltage (OV) deviation , this FET is used as differential am- plifier and operates at cross point which is the optimum point of drain current (at about 3mA) against the tempera- ture drift. OTransistors, TROS and TRO? , the push-pull pre- driver stage functions as current differential amplifier that the stabilized operation can be obtained. In addition , the collector cur- rent of these transistors is enough high to make linearity excellent. OSince this Amplifier employs phas~ advancer circuits (CO6 COB, C1S, R29 , C16 and R30J, which have not been fre- quently used , to compensate the phase characteristics on high frequency range and is also made to have enough 4. ADJUSTMENTS 1. Driver Circuit Board Adjnstments Note: 1. STEP IMaster Volume.... ........ ........ Minimum RoomTemperature................ SUBJECT I EQUIPMENT I MEASURE OUTPUT Icurrent on each stage to increase the through-rate , the performance on high frequency range is conspicuously improved. OTo avoid the voltage deviation, regulated power supply circuit composed of ZDO1, ZDO2 is employed. 2. Operation The use of differential amplification at first stage dual FET (FETO1, FETO2) and connection of the FET to the differential amplifier composed of TRO1, TRO2 , make possible to obtain enough gain and remarkable low distortion. The output signals of TRO1 and TRO2 are untiphase. The output signal of TRO2 adds to TROS , on the other hand the output phase of TRO1 is inverted by TRO3 , then, it becomes input signal of TRO4 and TRO? which are cascoded connection. The output signals at TROS and TRO? are inphase that the op- eration of this stage is push- pull drive and current differential amplification. The power amplifier of the final stage is com- posed ofSEPP (Single Ended Push-Pull) symmetry comple mentary in 3- stage darlington connection type. TRO9 and TR10 are composing current limiter circuit to protect power transistor from break- down by overload. (See the picture of top view on page 3. For adjustment, run the unit for more than 3 minutes after the power is switched on. ADJUST ADJUST FORCONDITION DCOVDC Volt MeterSpeaker TerminalF-2721DC OV:tSmV0 Set VRO1 and VRO2 to center L-CHVRO1, VRO2 position. 0 Then , for the purpose of pro- DCOVSame as aboveSame as aboveF-2722DC OV:tSmVceeding the accurate adjust- ment, set the voltage to 0 volt VRO1, VRO2 by VRO1 first and VRO2 next. Bias CurrentSame as aboveTP Terminal (+) (-)F-2721DC 20mV:t1mV0 By turning VRO3 counterclock- of F-2721VRO3wise, the bias current is de- creased gradually. Bias CurrentSame as aboveTP Terminal (+) (-)F-2722DC 20mV:t1mV of F-2?~VRO3