Akai-1700-tape-sm维修电路原理图.pdf

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1、ILAKAI TAPE REGI|RDERooANDtoMolf Etl7l7RadioFans.CN 收音机爱 好者资料库IASTE OF CONTENTSI spEctFtcAnoNs. . . II HOW TO A.TEASURE DESIGNATED VALUES OFSPEC|F|CAT|ONS.,. . 2I tocafloN oF coNlRor.s . . ., 3IV DrsAssEMrLy oF tApE TRANSPoRT uNtTsAND AMPL|F|ERS. . . . ,lv TRANSPORI MECHAN|SL . . 6IJ ADJUSTMENT OF T

2、APE TRANSPORT UNIT . 9II ADJUSTMENT oF al4pr|FrER . . .10rlf r,A|NTENANCE pRocEDURES . . .ItX( Lrsl or REPLACEI ENT pARTs.12X ExpLoDED vtEw oF coMpoNENt pRTs. .,.1,4xI TROU3LESHOOTTNG CHART .,.,.21n scHEfiATtC DTAGRAM .,.,., .25xI CoNNECTING DfAGRAl.r .-.-.-.-.-.-.26RadioFans.CN 收音机爱 好者资料库SPECIFICAT

3、IONSMODELNUMBERwtrGHT (NETIN CARTON)DIMENSIONSPOWER RE-qUIREMENTSPOWER CON.SUMPTIONRECORDINCAkai Modcl 1700, portablc 4-trackst.rco tape rccorder.33 lbs (15 kg) without acccssorics.t3-t6 lH) x 13-% (w) x 9 (Dl caseA. C. 100, ll0, 120,200,220 or 240 voltsinterchangabl. 50 60cycles.80VA.Inline 4 t.ack

4、 streo and 4-tfack mon-Inlin 4.tiack stefeo, monaural play-Thrce speedscml and l-% (a.is cmJ per second. (15pr scond with an optional accessorycapstan and pinch wheI.)SYSTEM:PLAYBACKSYSTEM:TAPE SPEED :.IAPE SPEEDDEVIATION :WOW ANDFLUTTER :TIMEFRDqUENCYRDSPONStrDISTORTIONSIGNAL-TO-NOISE RATIOCROSS TA

5、LKCHANNELSEPARATIONLess than + 3 pef cent at all tapeLess than 0.2 % at 7-t6 ips. R.M.S.Less than 0.3 % at 3-7a ips. R.M.S.Less than 0.45 % at l-16 ips. R.M.S.FAST FORWARDAND REWIND150 seconds fof 1,200 ft. tapc at 50 cy-cles and 120 sconds at 60 cyclcs.40 to 18,000cps. at 7-%;ps;.L 3 db.80 to 12,00

6、0 cps. at 7-l, ipsj+ 3 db. 80 to 10,000cps. at 3-3la;ps;+ 4 db. 80 at 4,000cps. at l-7s ips.Within 4%at l,000cps,oVU ltotal40 db below rccorded levlsignal at allWithin 55db between each trach.Better than 80 db at l,000cps +3 VU.POWJR INPUILDVELS:POWDROUTPUT:Microphone ir)put lcvcl-55 db (VR. max.jat

7、 l,000cps.Phono and radio input levcl40 db (VR. max.)at l,000cps.Pre-Amplifier output, 0.7V at 1,000cps, impedanc more than l00K ohms.Main output,34dbm. up (in 600ohmt.More than 50MEC ohns.More than ore m;nute at A.C. 1,000V.With headphor during reco.ding.Condenser start;ng induction two-l/l00HP. Po

8、wer factor,70 pe. cent.2,900 to I,450 r.p.m. at 50 cps,3,480 to 1,740 r.p.m. at 60 cps.lnline +tf ack stereo/monau.al record-play had ;Impedance. .3,500 ohms + l0 % ztI,000 cps.4-track erase head ;Impdanc. . .4,000 ohms +15% at 90Round dynamic micropho.eImpedance.50,000ohmsSDsit;vity. 55 db.f.quency

9、 RrpoDse.70 ro 15,000Two 5x7 dynahic speakers.Impdance.8 ohmsAllowable IDput.6 wartsFrequency Rsponse.8o ro 12,000cps, :! l0db.I2AT7 x2, 6BM8x2.l50Dx2Up to 7 relINSULATIONRESISTANCEINSULATIONYI,LDSTRENGTHMONITORINCSYSTEMMOTORHEADSMICROPHONEUSED :SPEAKORINCLUDED:TUBES USED :SILICONDIODE USED:REELS US

10、ED :RECORDINGLEVELINDICATOR : Horizontal, A-model VU mte.RadioFans.CN 收音机爱 好者资料库1IIIOW TO NIICNSURE DESIGNATED VALUES OF SPECIFICATIONSTAII SPDtrDDEVIATION :OW ANDFLUTTER :Reco.d the l,000cps. sine curve ofthe tap speed at rating speds witha standa.d sound recorder (AMPEX351A, for instance) which is

11、 little af-fccted by lhe tape sPecd deviationtlrroughout the whole ingth of thetape. Put th;s standard taPe on thtapc recorder unde. test for playingback, and nreasure its outPut bY acouDte., then codvert thc value intorating power frequeDcy to cvaluatethe tape speed dcviatior.Fo. a rough measuremen

12、t, the taPesped deviation can also be measuredwith a testing tape for speed by astopPlayback thc 3,000cps sianda.d tapethat guarantes wod and flutter with-h 0.07 pr cent, aid read the effect;vevaluc otr wow mere.Since the sedsibility of wow and flut-tcr frequency bclow 2cps and above5 cps. d.ops, th

13、e frequency over 5cps.is put to 3db/OCT circuit, and thfrequency bclow 2.ps. is put to 6db/OCT circuit for adjustment This ad-justed value is called auditory com-Connccr to thc input tcdninal of thercco.dcr, .ccord a sine curve swecpf.equency at 100 cps -10 db. fromAudio frequency Oscillator.Adjusl

14、toDe volume to flat, playbackthe tape by .onnectidg VTVM tosp-aLr out put then read the frequencyresponse to adjusl a maximum devia.RLqUINCYRESPONSE:(OVIRALLIREqUENCYRESPONSE)TOTAL HARMONICDISTORTIONFACTOR: Provide the input terminal ol the,ecord.r with 1.000.ps. :nF , urvFsignals and .ecord these s

15、ignals on arecording tape at the zero level on therecorders VU mete.Then playback the siSnals under theno.mal recording condit;on to meas-u.c the distortion factor by an oscillator. Remove the recording tapcfrom the recorder, then read the noisclcvelon the oscjllator to 8ct the requ;r-d dhtortion fa

16、ctor by the followingformula:d0:d-dl d2d0.requiredd.overall distortion factordl.noise lveld2.disto.tion factor of the oscilla-to. uscdSICNAL TONOISE: Playback the sine curve, 250 cPS. taperccorded on a standard recorder onth reco.der to measur the voltagRemovc the taPe, then measure thenoisc level u

17、nder the same conditionCalculate the ratio between the twoin dcibel.OUTPUT:Ilayback on the recorder thc 1,000 cps.sine curvc tape which was recorddat the zero VU level on a standardrecorder. TrDinatc the test recorderwith ight ohms.Square the voltag rcading, then divide the figure by eight ohms to g

18、etthc r.m.s. Powcr output.CROSS TALK: Record 1,000 cps. signal at +3VU onthe third tack, then playback thissignal through a l,000cps. Band PassFilter.Compare the output of tracks I and 3in decibels.2-RadioFans.CN 收音机爱 好者资料库fILOCATION OF CONTROLS(D(Doooo0oooo(D(DSupply rccl shaftCyclc convcrsion swit

19、chCapstan storage postTape guidetrras headRight channel volumc controlRight channel tonc controlLeft channcl microphone input jackRight channel microphone input jackLeft channel volumc cont.olLeft channel tone controlSpeed change switchTake-up reel shaftCapstan shaftPinch wheelAutomatic stop leverRe

20、cord/Play switchRewind/FasFforward switchRecord safety buttonAutomatic stop switchStereo headphonejackVU hter convrsion switchTrack slector switchCycle conversion sw;tchHum adjust (right)Speaker output jack (righr)Speaker output jack llert)Voltage sele.tor switchPreamp output jack (right)Preamp outp

21、ut jack left)Phono/Radio input jack (lftHun adjust (left)Phono/Radio input jack (rish03RadioFans.CN 收音机爱 好者资料库II DISASSEMBLY OF TAPE TRANSPORT UNITS & AMPLIFIERSll l-oo!, rh. lt l:.1. I lN(; SUIlllf irlof IINCIt R()L-LIl , ,lt-. ,vl,v , !iih. lIN(ill lt()l.l.l lt llil.13) L,iJ.! thc S(lltliS nrxrl.(

22、l 1,) r.ri r(j tll i,r (1,.r ror.! l)1lCK l).l.ll. tl)1.12 l.(.,tr | tlx. I)llUK C( ) l R( )I- ti( )lls ialrnd iblbyio,!c,i,ig d,cif ritx;fing s.raL. u;i)g r I)liillips h.adcdo99r.tI(11 l.oosci (h(i S(iltl:,S,)rrk.d f,or) i.t r,) ktr.IRadioFans.CN 收音机爱 好者资料库(5) Loosen the SCREWS narked from a) to (d

23、).Lifl TAPE DECK andcabinet (B).AMILIFI liR (Dr trm ,he(7) Disconnect the PINS of speako marked a) and (d), thePLUGS or motor marked () and (f) and the PINS ofhead marked B)and j).(8) Loosen the RETAINING SCRDWS of dcck framemarkd from (al to id)(9) SEPAAIC TAPE DtrCK (M) frOM AMPLIFIER (A).RadioFan

24、s.CN 收音机爱 好者资料库YTRANSPORT MECHANISMDriving of CapstanFjgure l.Aj Motor(B) Driving Belt (flat belt)(C) Capstan(D) FlYwheelHigh-speed rotation of Mot / (A) is reduced by D/trireBr, (B) and transmitted to Capstan (C), which is connectedto Flywheel with ample inertia and nables rated rotaiionby absorbin

25、g mino. rotation distortion ofDotor itself.Capstan Rotation 606 r.p.m. at 7-%(l9cn)pe. sec.303r.p.m. at 3-%(9.5 cm) per sec.l5l.5r.p.m, at l -16 (4.7s cmlper sec.Motor Rotation 2,900 to 1,450 r.p.m. at 50 cps.3,480 to 1,74r.p.m. at 60cps.Fig. IDriving of Pinch RollerPut tape between rotating capstan

26、 and pinch roller andpush pinch rouer against capstan, this will transport thctape at ratd sped. Th appropriate pressure of pinchroller is between I,000 to I,150 grams at the tape spedof 7-% (19cm) per scond.Rcoding and Play BackTuJ rhe RECORD, PLA rB,4Cf knob (A) to PLAYposition, and pinch roller p

27、resses against capstan to movetape at the rated sped. At the same time, Idlel (B) movesbetween Motor &tshitag ICI znd t:e Tahe-Ut Reel SpindlelD) b rrnslr.it the motol /rldtro, to D) so that th tape ismoved and wound on the take-up reI.The Tak-Up Reel Spindle Base is made up of two plas-tic rollers

28、(l and 2l with a clutch felt in betwn. The ldleris rottitg the plastic mUel (2) under. Therefore, the tape-winding friction is adjustd by the slipping of the felt toenabl rated winding of the tap.on the other ha d, the S*pfb Reel Sbtndle IHI hs aBlake lo e/ lEl hwg on the Plastic Rollr 4) under whic

29、hprovides app.opriate back tension by the .lutch fet slipp-ing to the rotation ofthe Pully (3)above.To prevent accidental ersure, the Record lnterloch But-to, (F) mut be depressed before the RECORD, PLAY-BACK knob can be moved to the REC position. TheSafet! dnice lclls depressed to ente. the record

30、mode(See Fisures 2 and 3)ffiirSlipping RotationFig. 2-6-RadioFans.CN 收音机爱 好者资料库fFAST-FORWARD MECIIANISMTurD lie aASZ FWD-REWIND *no, (A) to FASTFWD position, and lls ca- (B) undcr lhc knob pushes upthe Lerer (C). The l.tler (D) moves into the spacc bctweenthe Plast c Rouer lF) above the Take-Up Reel

31、 Spindle andthe uppe. part of th. rotating motor drive bushing totransm;t the motor rotat;on to the takc-up reel spindle. Atthe same tihe, Brale RoUerc lH) and (I) cone otr the reelsp;ndle to free lr, Srrrl! Reel Sti dlelcl,rheteby allowiDTfast windnrg ofthe tapc onto thc iakc-up rcel.(Sec ligures 4

32、 and 5)FreeRolarion Fl;gh-SpeedRotationFig. 5Fig.4oREWIND MECHANISMf utn the FAST FWD-REtl/N, izo, (A)ro REWINDposition, and the cam lB) udet $e kob ptshes the LeuerlC) up. The ldlerlDl noves into thc space betwecn the up-per part of the rcIating Motar dtue bushing lE) and theInterned ate Pulle,lF)

33、to hansmit the high-speed rotationof themotor through the intermdiate pulley to tr? SrrrllReet Spindte lC). At the sahe time, Brale Rollls (H) and (I)come ofl the rel spindle b tree the take-at leel spindte lJl,therby rewinding the tape into rhe supply reel ar a fast(See F;surcs 6 and 7)HighSpeed Ro

34、tationFig. 7J YOo(a) sToPoo(b) FAST-FORWARDo(.) REWINDooId) RECORDINGooSTOP CONTROLPush ihc stop lever to STOP positlon, Bruke Ro elsA) and 1B) depres reel spindles to stop .otation of the reelsp;ndles.As thc brake rubbr depfesses the plastic rolleG underthe .eel spindles, no triction works on the t

35、ape itslf.Supply R*l Spindle R*ind ldle$heel Take-up Reel SpindleNOTES : x -marks indicates open andO-ma.ks engagedfig. 87(RadioFans.CN 收音机爱 好者资料库RDCORD/PLAYBACK CIIANGING MECHANISMBy turning the RLCORD/PLAYBACK KNOB (N)to the recording position, thr LEVIiR 1a)pulls the RECORDINGLEVER (bi and (c), a

36、s ;llushated in dotted l;nc, then the RECORD/PLAYBACK CHANGD SWITCH (SWl)turnsto .ecording position.If the LIVER (c)do.s not turnThen must adjust the LI.VIRpropc.ly. SWI docs not operatc prope.ly so may occu. the abnormal oscillation and(cl to proper position by loos;ng thc SCREW lcll. r il., - ,z-I

37、tz_,/.r,l-a11;: ,./.(/,-:,. ,/l/ /.)._u. ,4) _JWtRadioFans.CN 收音机爱 好者资料库rU ADJUSTMENT OF TAPE TRANSPORT UNIT1. ADJUSTMENT OF PINCII WIIEELIt is imporlant that the piich wheel shaft i5 kept nrcomplcte alignmentwith the capstan shaft. A properpinchwheel pressur is bctween 1.000 and I,150 grahs whcn th

38、eunit is ope.ated at the tapc spccd of7-t6 ips. Any deviation from this specificalion will result in wow and flutter.Check Iin.h wheel presu,. bv r .1-.ring cale at.d. ifr,ecesar y. ad jur rhe pin, h whpFl load 5t.inB.2, ADJUSTMENT OF TAKE.UP IDLER WHEELThe take-up ;dlm wheel must be kcpt in complet

39、e align-ment ltith thc takc-up reel shaft. Whcn the unit is set infast forward condition, thc idler whel will contact to theupper knu.led wheel of the takc-up reel shaft assembly.and it will contact to thc lower kn urled whccl du.ing recordor play modc. Adjust idlerwhccl load spr;ngsoihatlhcidler wh

40、eel pressurc is kept between 50 and 80 grams. The;dler qh.l rapidlv wear. :f Ihf pre*u,. b Px,.ssic.The slippage occurs if thc prcssu.e is smallef thaD the3. ADJUSTMENT OF REWIND IDLER WSEELThe .crind idler whccl must be kcpt in complete align-mcnt with thc rewi.d reel shaft. The amount of pressurct

41、o the k,urlcd motor bushing should be maintained about50 gfams during rewidd ope.ation. Adjust both thc idlerload spriog aDd rewind roller.4. ADJUSTMENT OF INTERMEDIATE WHEDLThc intcrnediatc wheel is located between the rewindidler whccl and thc rubbe. ring vhich is uscd on the uppe.part of the supp

42、ly reel shaft assembly. When the unit issct in rewind mode, it will contact to thcsc parts sihul-taneously deliverins torque of motor. An adequate pres-su.cis50grams. Adjust thc load sp.;ngofthc inrermed;atewheel if the pressure is not sufrc;ent.5. ADJUSTMENT OF TAKE-UP REEL SIIAITASSEMBLYA felt clu

43、tch mat.rial is attachcd to the bottom sid olthe reel table basc plat so that reco.ding tapc w;ll not bcstretched during lhst forwafding operation due to excesivctension. To check the amoudt of friction of this part, placa Sinch reel with fecordins tape wound by 60m/m indiameter, and gently pull the

44、 cnd of tapc upwarcl using aspring scale. Adjust the conical sp.ing so that thc amountof tension at this part will bc kept between 400 to 500grams. Anothr felt clutch matoial ;s attached to thetakc-up drive wheel. It is to pfovide proper slipping opc-ration du.ing record or play modc. The procedu.e

45、forcheckins friction of this part ; same as the foregoing, andbetween 120 and 200 grams of frictioD will provide thebest result. Adjust the star-shapcd spring jnst under thetakc-up dr;ve whcel. lvhen the unit is set in rewindmode, the amou.t of f.iction of this part will greatly bereduced and viil b

46、ecome I0 to 20 grams. Check to sccrvhether this is satisfactory ;f iot, readjust the star-shapedspring fo. Bfakc, and spring rctainef washed accordingly.lscc fisure ll (al at lefo6. ADJUSTMENT OF SUPPLY REEL SIIAFTASSDMBLYA felt clutch matoial is uscd between the love. side ofthc reel table base pla

47、te and the .ewind rubbcr ring toprotect reco.ding tape from an excesive tension th;le re-winding operation. To check thc amount offriction of thispa.t, place onto thc supply reel table a 5-inch rcel withrcco.ding tape wound by 60m/m in diameter and gentlypulL thc cnd of tape upward by a spring scale

48、. Adjustthc conical sp.ing so that thc amount of tens;on ;s keptbctwecn 400and500grams. Anothc. fclt clutch is attachedto thc rev;nd drive wheel to provide proper sl;ppingope.atioD cluring reco.d or play mod. The procedurefor checkn)g friction of this part is same as the foregoing,and betwen 80 and

49、120 s.ams of friction will give thebest result. Whcn the unit js set ;n fasi forward modc,the amount of f.;ction will greatly be reduced and willbecome l0 to 20 grans.Check to sce whether this is proper, if not, rcadjust coilspring and spring rtainer washc.See figure I I (b) at left)7. ADJUSTMENT OF

50、 TAPE HEADA vertical azimuth alignment of tape head is the onlyadjustment that can be made at the field of service. Toalign tape head, play 8,000 cycles recordcd on an AmPxstandard alignment tape. Rotate th azimuth al;gnmentsc.ew until a maximum playback level through the smallhole which is position