Pioneer SX-3800 Blockdiagramof PD5009, G 6 D 1 D 5 t i m e d i v i s i o np u l s es i g n a l s

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O I G I T O R I V E R

S E G M € N T D R I V E R

M U ! T I P L E X E R

P R E S E T A E L € 5 - D I G I T

O E C I M A L C O U N T E R

2 2 - 8 l I r 1 6 R O M

G N D

Fig . 4 - 5 Blockdiagramof PD5009

I

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val. Pin no.? of PD5009 is the brightnessselector terminal. The time division pulse width is set to 8009s for H level input signals,and to 200ps for

Llevel signals,thereby varying the degree of FL tube brightness (by varying the segment lighting period). Note that since the pov.er indicator FL tube is driven by static drive, the degreeof bright- nessmay be varied by changingthe grid voltage.

The 5.12MHz crystal oscillator generatesthe basic signai used in the preparation of the time division pulse signal and the counter gate circuit

control signal.

Terminals S1 - S4 (pin nos.3 - 6) are used in designating reception mode. The 2 reception modesemployed in the SX-3800 (seeTable 1) are designatedby varying the combination of input levels (H and L). The 3 different IFs during FM mode are required in coping with IF offset in the IF ceramic filter stage, 53 and 54 being preset during FM mode according to the ceramic filter characteristics.

Although the SX-3800 FM stage quartz-lock system is capable of locking any frequency within the FM band, the L0kHz digit (digit in the second decimal place) in the FM frequency display will appearonly as 5 or 0.

The frequency display FL tube alsoincorporates the TUNING and SIGNAL indicators. And al- though the segments(anode) for these indicators are static driven by the corresponding drive cir-

cuits, the edd is driven according to the D3 time divisionpulsetiming, therebyplacingthe segments

o,wI n l l t t r -

o o M

*l-w

,,iw 8 C = L ( D l M )

- ' l ' * i * i i l l

t{-- tm3 +

F i g . 4 - 6 D 1 - D 5 t i m e d i v i s i o np u l s es i g n a l s

under dynamic drive. In addition, the AM and FIW indicators in the frequency display section are lit accordingto the Db timing, while the kHz and MHz indicatorsarelit accordineto the D1 timine.

MODE

s1

S2

s3

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H

L

L

H

1 07 3

F M

H

L

H

L

1 0 . 7 0

 

H

L

H

H

't

 

0.67

A M

L

H

H

L

4 5 0 k H z

T a b l e1

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Contents Sefvice nual FM Ouartz Locked SixSTEREORECEIVER-gaooContents H H T H HFM TunerSection P E C T F T C a T I O N STo 20000Hertzt02dB Or, iori ,ro i ,ou OdBMiscellaneous Eix-3El00ISemiconductors FurnishedPartsGnlcHrNEss @sELEcroR Tront PanelfacilitiesSpERrERswtrcHEs @ bunnrz LocKEDtNDtcAToR@ volunnEcoNTRoL GRl-Rr\cE @coNTRoL@f--q-*@ Block Diagram1l , or LhTjl 68-llFig 1 Choppertype switchingcircuit Switchins,is.rc-1q/ t h LCompositesignal CircuitdescriptionsSx-gaoo Mode Fig 5 Blockdiagramof PD5009G 6 D 1 D 5 t i m e d i v i s i o np u l s es i g n a l s B l e1Signal lndicatorCircuit Fig .4 7 SIGNALindicatordrivecircuitFig 9 Poweramplifier More,becanselhere is no time clonstantin the NFB Excellent high frequency characteristicscomparaBle lo those of a small-signaltransistor.Further Circuit ir-rthe lorv-frecluencyregion, amplificationFig .4 12 Power indicatorcircuit O W E R N D I C a T O RC I R C U I TOverloadDetector Deenergized, thus causing the output circuit toBecome de-energized,thus causing the ourpur Overload detector circuit incorporatesDisassembly Front panel Bonnet case Bottom plateRearPanel Parts LocattonFront View with PanelRemoved AKE.O54Ia.i TUNERAssy GWE-133+I t i t Rrprro&ffi$ll1rl + +D16l IlIlE0UALIZERAssy AWM-227 INDICATORAssy AWV-OO9LiTtFTTTTTTT- - 1 * l l l l t t Rtrf TiiI t TONECONTROLAssyTttt,,.,i%hi*i*U E i t t l i 6 Y# x r , o 8lr rorAL2oowMAx AI I h-l# *n LmfiiOl!6 - j,r-l*-,,-s-l = # . = - r?tA tlDzrT 4u- @ *ronce $r-ffir Nffi3lilli FfTJ-ir S5flsIFuse64 BottomViewTop View GWEN i n gd r u m Dialshaft Startingpoint Dialpointer I a L C O R D S T R I N G I N GDial pointer ArrrrTl AdjustmentsGK 6 To FM300n ANT terminals MPXsignalgeneratorConnectSIGNALmeteror DC voltmeter AC voltmeter Distortionmeter R E Ct e r m i n a lAC voltmeter To RECterminal R a n t e n n ac o i l AM signalgeneratorTo AM ANT 1kfl resistor TerminalFis .8 LvR5ll AFosc,lt ,-d + u tFJaJtuL6 \ ,v\ Te ,t . 1Fig .8 FL indicatorassemblyVR2*€ @vnr PD5009VBZ3OPOSOFMC ExteriorComponentsAAB.24O AcN lrs Interior ComponentsRo. AEK-rog 25 e6Ae*-\ 228? T SX.SClOl Fr-r rHeat Sink Block H 1 3N n n n t Illl\Usr E6nmr TunerAssemblyGWEAN,,4Sa NrrezZS3,s4 PrecautionsC65,C66,C70,C71 c63,C64 C303,c304 Arc-o72SwitchAssemblyGWS-226 ToneControlAssemblyt G W G 1 4AWS-146 SwitchAssembly Lynlgt9 9*ie9Ncru-rat PowerAmplifierAssemblyGWH-139Nr21, R12z PowerSupplyAssemblyGWR-j22 9yqlglt o*lelglSpeakersTerminalAssemblytGWS-222 FL IndicatorAssemblyAWV-009SwitchAssemblytGWS-223 AR8-355 A C K I N GADH AHD 7s5FM Ouartz Locked StereoreceiverP E C F I C a T I O N S With exceptionof thissupplementsSrs Contrastof Miscellaneous Parts$ r u r IBi ihl*cr SCHEMATICDIAGRAM,P.C. Board PatternsandRd.*dr q l Parts List Il,*3Lr-l--.q.iliffi 3il3i!11UJl--J RtmlSX-3EtCO/si/GirS 11ffiflCl, c2 €tX-ggtOO/gi/GlrsAWS-148 C3,c4

SX-3800 specifications

The Pioneer SX-3800 is a classic stereo receiver that emerged in the late 1970s, embodying the high-fidelity audio aspirations of its time. As part of Pioneer’s widely respected SX series, the SX-3800 is hailed for its exceptional sound quality, robust construction, and an array of features that cater to both audiophiles and casual listeners alike.

One of the SX-3800's standout characteristics is its power output. It delivers a solid 80 watts per channel into 8 ohms, making it capable of driving a variety of speaker systems with ease. This ensures a dynamic audio experience, with clear highs, rich midrange, and deep bass. The receiver also exhibits low total harmonic distortion (THD) ratings, which means the sound produced is clean and faithful to the original recording.

The SX-3800 is equipped with a high-quality AM/FM tuner, which is known for its excellent sensitivity and selectivity. Featuring a large analog dial, it allows users to effortlessly dial into their favorite stations while the signal strength meter helps in fine-tuning the reception. This tuner is complemented by Pioneer’s proprietary Auto-Seek tuning function, making it easier for users to find and lock onto stations.

In terms of connectivity, the SX-3800 comes with several inputs and outputs, including phono, tape, aux, and multiple speaker outputs, offering flexibility for various audio setups. Additionally, the built-in phono preamp ensures that vinyl lovers can connect their turntables with ease, preserving the rich detail and warmth that analog sources are known for.

Another technological highlight of the SX-3800 is its inclusion of a loudness control feature, which allows users to enhance the low and high frequencies at lower volume levels. This feature is particularly useful for late-night listening or in quieter environments where detail is essential but loudness is not an option.

With its solid construction, vintage aesthetics, and a beautiful wood finish, the Pioneer SX-3800 not only performs well but also adds a classic touch to any audio setup. Its blend of features, performance, and timeless design continues to make it a desirable component in the world of vintage audio equipment. Collectors and enthusiasts appreciate the SX-3800 not just for its sound quality but also for its enduring legacy in the rich history of audio technology.
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