Akai-1700-tape-sm维修电路原理图.pdf

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1、I L AKAI TAPE REGI|RDER oo AND to Molf Et l7 l7 RadioFans.CN 收音机爱 好者资料库 IASTE OF CONTENTS I spEctFtcAnoNs. . . I I HOW TO A.TEASURE DESIGNATED VALUES OF SPEC|F|CAT|ONS.,. . 2 I tocafloN oF coNlRor.s . . ., 3 IV DrsAssEMrLy oF tApE TRANSPoRT uNtTs AND AMPL|F|ERS. . . . ,l v TRANSPORI MECHAN|SL . . 6

2、IJ ADJUSTMENT OF TAPE TRANSPORT UNIT . 9 II ADJUSTMENT oF al4pr|FrER . . .10 rlf r,A|NTENANCE pRocEDURES . . .It X( Lrsl or REPLACEI ENT pARTs.12 X ExpLoDED vtEw oF coMpoNENt pRTs. .,.1,4 xI TROU3LESHOOTTNG CHART .,.,.21 n scHEfiATtC DTAGRAM .,.,., .25 xI CoNNECTING DfAGRAl.r .-.-.-.-.-.-.26 RadioFa

3、ns.CN 收音机爱 好者资料库 SPECIFICATIONS MODEL NUMBER wtrGHT (NET IN CARTON) DIMENSIONS POWER RE- qUIREMENTS POWER CON. SUMPTION RECORDINC Akai Modcl 1700, portablc 4-track st.rco tape rccorder. 33 lbs (15 kg) without acccssorics. t3-t6 lH) x 13-% (w) x 9 (Dl case A. C. 100, ll0, 120,200,220 or 240 volts int

4、erchangabl. 50 60cycles. 80VA. Inline 4 t.ack streo and 4-tfack mon- Inlin 4.tiack stefeo, monaural play- Thrce speeds cml and l-% (a.is cmJ per second. (15 pr scond with an optional accessory capstan and pinch wheI.) SYSTEM: PLAYBACK SYSTEM: TAPE SPEED : .IAPE SPEED DEVIATION : WOW AND FLUTTER : TI

5、ME FRDqUENCY RDSPONStr DISTORTION SIGNAL-TO- NOISE RATIO CROSS TALK CHANNEL SEPARATION Less than + 3 pef cent at all tape Less 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 FORWARD AND REWIND 150 seconds fof 1,200 ft. tapc at 50 cy- cles

6、 and 120 sconds at 60 cyclcs. 40 to 18,000cps. at 7-%;ps; .L 3 db.80 to 12,000 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 ltotal 40 db below rccorded levlsignal at all Within 55db between each trach. Better than 80 db at l,00

7、0cps +3 VU. POWJR INPUI LDVELS: POWDR OUTPUT: Microphone ir)put lcvcl -55 db (VR. max.jat l,000cps. Phono and radio input levcl 40 db (VR. max.)at l,000cps. Pre-Amplifier output, 0.7V at 1,000 cps, impedanc more than l00K ohms. Main output,34dbm. up (in 600ohmt. More than 50MEC ohns. More than ore m

8、;nute at A.C. 1,000V. With headphor during reco.ding. Condenser start;ng induction two- l/l00HP. Power 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 % zt I,000 cps. 4-track erase hea

9、d ; Impdanc. . .4,000 ohms +15% at 90 Round dynamic micropho.e Impedance.50,000ohms SDsit;vity. 55 db. f.quency RrpoDse.70 ro 15,000 Two 5x7 dynahic speakers. Impdance.8 ohms Allowable IDput.6 warts Frequency Rsponse.8o ro 12,000 cps, :! l0db. I2AT7 x2, 6BM8x2. l50Dx2 Up to 7 rel INSULATION RESISTAN

10、CE INSULATION YI,LD STRENGTH MONITORINC SYSTEM MOTOR HEADS MICROPHONE USED : SPEAKOR INCLUDED: TUBES USED : SILICON DIODE USED: REELS USED : RECORDING LEVEL INDICATOR : Horizontal, A-model VU mte. 1IIIOW TO NIICNSURE DESIGNATED VALUES OF SPECIFICATIONS TAII SPDtrD DEVIATION : OW AND FLUTTER : Reco.d

11、 the l,000cps. sine curve of the tap speed at rating speds with a standa.d sound recorder (AMPEX 351A, for instance) which is little af- fccted by lhe tape sPecd deviation tlrroughout the whole ingth of the tape. Put th;s standard taPe on th tapc recorder unde. test for playing back, and nreasure it

12、s outPut bY a couDte., then codvert thc value into rating power frequeDcy to cvaluate the tape speed dcviatior. Fo. a rough measurement, the taPe sped deviation can also be measured with a testing tape for speed by astop Playback thc 3,000cps sianda.d tape that guarantes wod and flutter with- h 0.07

13、 pr cent, aid read the effect;ve valuc otr wow mere. Since the sedsibility of wow and flut- tcr frequency bclow 2cps and above 5 cps. d.ops, the frequency over 5cps. is put to 3db/OCT circuit, and th frequency bclow 2.ps. is put to 6db/ OCT circuit for adjustment This ad- justed value is called audi

14、tory com- Connccr to thc input tcdninal of the rcco.dcr, .ccord a sine curve swecp f.equency at 100 cps -10 db. from Audio frequency Oscillator. Adjusl toDe volume to flat, playback the tape by .onnectidg VTVM tosp- aLr out put then read the frequency response to adjusl a maximum devia .RLqUINCY RES

15、PONSE: (OVIRALL IREqUENCY RESPONSE) TOTAL HARMONIC DISTORTION FACTOR: Provide the input terminal ol the ,ecord.r with 1.000.ps. :nF , urvF signals and .ecord these signals on a recording tape at the zero level on the recorders VU mete. Then playback the siSnals under the no.mal recording condit;on t

16、o meas- u.c the distortion factor by an oscil lator. Remove the recording tapc from the recorder, then read the noisc lcvelon the oscjllator to 8ct the requ;r- d dhtortion factor by the following formula: d0:d-dl d2 d0.required d.overall distortion factor dl.noise lvel d2.disto.tion factor of the os

17、cilla- to. uscd SICNAL TO NOISE: Playback the sine curve, 250 cPS. tape rccorded on a standard recorder on th reco.der to measur the voltag Removc the taPe, then measure the noisc level under the same condition Calculate the ratio between the two in dcibel. OUTPUT: Ilayback on the recorder thc 1,000

18、 cps. sine curvc tape which was recordd at the zero VU level on a standard recorder. TrDinatc the test recorder with ight ohms. Square the voltag rcading, then di vide the figure by eight ohms to get thc r.m.s. Powcr output. CROSS TALK: Record 1,000 cps. signal at +3VU on the third tack, then playba

19、ck this signal through a l,000cps. Band Pass Filter. Compare the output of tracks I and 3 in decibels. 2- f ILOCATION OF CONTROLS (D (D o o o o 0 o o o o (D (D Supply rccl shaft Cyclc convcrsion switch Capstan storage post Tape guide trras head Right channel volumc control Right channel tonc control

20、 Left channcl microphone input jack Right channel microphone input jack Left channel volumc cont.ol Left channel tone control Speed change switch Take-up reel shaft Capstan shaft Pinch wheel Automatic stop lever Record/Play switch Rewind/FasFforward switch Record safety button Automatic stop switch

21、Stereo headphonejack VU hter convrsion switch Track slector switch Cycle conversion sw;tch Hum adjust (right) Speaker output jack (righr) Speaker output jack llert) Voltage sele.tor switch Preamp output jack (right) Preamp output jack left) Phono/Radio input jack (lft Hun adjust (left) Phono/Radio i

22、nput jack (rish0 3 II DISASSEMBLY OF TAPE TRANSPORT UNITS SUIlllf irlof IINCIt R()L- LIl , ,lt-. ,vl,v , !i ih. lIN(ill lt()l.l.l lt llil. 13) L,iJ.! thc S(lltliS nrxrl.(l 1,) r.ri r(j tll i,r (1,.r ro r.! l)1lCK l).l.ll. tl)1. 12 l.(.,tr | tlx. I)llUK C( ) l R( )I- ti( )lls ialrnd iblby io,!c,i,ig

23、d,cif ritx;fing s.raL. u;i)g r I)liillips h.adcd o 99 r.t I (11 l.oosci (h(i S(iltl:,S,)rrk.d f,or) i.t r,) ktr. I (5) Loosen the SCREWS narked from a) to (d). Lifl TAPE DECK and cabinet (B). AMILIFI liR (Dr trm ,he (7) Disconnect the PINS of speako marked a) and (d), the PLUGS or motor marked () an

24、d (f) and the PINS of head marked B)and j). (8) Loosen the RETAINING SCRDWS of dcck frame markd from (al to id) (9) SEPAAIC TAPE DtrCK (M) frOM AMPLIFIER (A). YTRANSPORT MECHANISM Driving of Capstan Fjgure l. Aj Motor (B) Driving Belt (flat belt) (C) Capstan (D) FlYwheel High-speed rotation of Mot /

25、 (A) is reduced by D/trire Br, (B) and transmitted to Capstan (C), which is connected to Flywheel with ample inertia and nables rated rotaiion by absorbing 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 -1

26、6 (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. I Driving of Pinch Roller Put tape between rotating capstan and pinch roller and push pinch rouer against capstan, this will transport thc tape at ratd sped. Th appropriate pressure of pinch roller

27、 is between I,000 to I,150 grams at the tape sped of 7-% (19cm) per scond. Rcoding and Play Back TuJ rhe RECORD, PLA rB,4Cf knob (A) to PLAY position, and pinch roller presses against capstan to move tape at the rated sped. At the same time, Idlel (B) moves between Motor t the motor rotat;on to the

28、takc-up reel spindle. At the same tihe, Brale RoUerc lH) and (I) cone otr the reel sp;ndle to free lr, Srrrl! Reel Sti dlelcl,rheteby allowiDT fast windnrg ofthe tapc onto thc iakc-up rcel. (Sec ligures 4 and 5) FreeRolarion Fl;gh-SpeedRotation Fig. 5 Fig.4 o REWIND MECHANISM f utn the FAST FWD-REtl

29、/N, izo, (A)ro REWIND position, and the cam lB) udet $e kob ptshes the Leuer lC) up. The ldlerlDl noves into thc space betwecn the up- per part of the rcIating Motar dtue bushing lE) and the Interned ate Pulle,lF) to hansmit the high-speed rotation of themotor through the intermdiate pulley to tr? S

30、rrrll Reet 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 Rotation Fig. 7 J YO o (a) sToPoo (b) FAST-FORWARD o (.) REWINDoo Id) RECORDING oo

31、 STOP CONTROL Push ihc stop lever to STOP positlon, Bruke Ro els A) and 1B) depres reel spindles to stop .otation of the reel sp;ndles. As thc brake rubbr depfesses the plastic rolleG under the .eel spindles, no triction works on the tape itslf. Supply R*l Spindle R*ind ldle$heel Take-up Reel Spindl

32、e NOTES : x -marks indicates open and O-ma.ks engaged fig. 8 7 ( RDCORD/PLAYBACK CIIANGING MECHANISM By turning the RLCORD/PLAYBACK KNOB (N)to the recording position, thr LEVIiR 1a)pulls the RECORDING LEVER (bi and (c), as ;llushated in dotted l;nc, then the RECORD/PLAYBACK CHANGD SWITCH (SWl)turns

33、to .ecording position. If the LIVER (c)do.s not turn Then must adjust the LI.VIR propc.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- Itz_,/.r, l-a11;: , ./. (/ ,-:,. ,/ l/ / .)._u. . ,4) _ JWt r U ADJUSTME

34、NT OF TAPE TRANSPORT UNIT 1. ADJUSTMENT OF PINCII WIIEEL It is imporlant that the piich wheel shaft i5 kept nr complcte alignmentwith the capstan shaft. A properpinch wheel pressur is bctween 1.000 and I,150 grahs whcn the unit is ope.ated at the tapc spccd of7-t6 ips. Any devia tion from this speci

35、ficalion will result in wow and flutter. Check Iin.h wheel presu,. bv r .1-.ring cale at.d. if r,ecesar y. ad jur rhe pin, h whpFl load 5t.inB. 2, ADJUSTMENT OF TAKE.UP IDLER WHEEL The take-up ;dlm wheel must be kcpt in complete align- ment ltith thc takc-up reel shaft. Whcn the unit is set in fast

36、forward condition, thc idler whel will contact to the upper knu.led wheel of the takc-up reel shaft assembly. and it will contact to thc lower kn urled whccl du.ing record or play modc. Adjust idlerwhccl load spr;ngsoihatlhc idler wheel pressurc is kept between 50 and 80 grams. The ;dler qh.l rapidl

37、v wear. :f Ihf pre*u,. b Px,.ssic. The slippage occurs if thc prcssu.e is smallef thaD the 3. ADJUSTMENT OF REWIND IDLER WSEEL The .crind idler whccl must be kcpt in complete align- mcnt with thc rewi.d reel shaft. The amount of pressurc to the k,urlcd motor bushing should be maintained about 50 gfa

38、ms during rewidd ope.ation. Adjust both thc idler load spriog aDd rewind roller. 4. ADJUSTMENT OF INTERMEDIATE WHEDL Thc intcrnediatc wheel is located between the rewind idler whccl and thc rubbe. ring vhich is uscd on the uppe. part of the supply reel shaft assembly. When the unit is sct in rewind

39、mode, it will contact to thcsc parts sihul- taneously deliverins torque of motor. An adequate pres- su.cis50grams. Adjust thc load sp.;ngofthc inrermed;ate wheel if the pressure is not sufrc;ent. 5. ADJUSTMENT OF TAKE-UP REEL SIIAIT ASSEMBLY A felt clutch mat.rial is attachcd to the bottom sid ol th

40、e reel table basc plat so that reco.ding tapc w;ll not bc stretched during lhst forwafding operation due to excesivc tension. To check the amoudt of friction of this part, plac a Sinch reel with fecordins tape wound by 60m/m in diameter, and gently pull the cnd of tapc upwarcl using a spring scale.

41、Adjust the conical sp.ing so that thc amount of tension at this part will bc kept between 400 to 500 grams. Anothr felt clutch matoial ;s attached to the takc-up drive wheel. It is to pfovide proper slipping opc- ration du.ing record or play modc. The procedu.e for checkins friction of this part ; s

42、ame as the foregoing, and between 120 and 200 grams of frictioD will provide the best result. Adjust the star-shapcd spring jnst under the takc-up dr;ve whcel. lvhen the unit is set in rewind mode, the amou.t of f.iction of this part will greatly be reduced and viil become I0 to 20 grams. Check to s

43、cc rvhether this is satisfactory ;f iot, readjust the star-shaped spring fo. Bfakc, and spring rctainef washed accordingly. lscc fisure ll (al at lefo 6. ADJUSTMENT OF SUPPLY REEL SIIAFT ASSDMBLY A felt clutch matoial is uscd between the love. side of thc reel table base plate and the .ewind rubbcr

44、ring to protect reco.ding tape from an excesive tension th;le re- winding operation. To check thc amount offriction of this pa.t, place onto thc supply reel table a 5-inch rcel with rcco.ding tape wound by 60m/m in diameter and gently pulL thc cnd of tape upward by a spring scale. Adjust thc conical

45、 sp.ing so that thc amount of tens;on ;s kept bctwecn 400and500grams. Anothc. fclt clutch is attached to thc rev;nd drive wheel to provide proper sl;pping ope.atioD cluring reco.d or play mod. The procedure for checkn)g friction of this part is same as the foregoing, and betwen 80 and 120 s.ams of f

46、riction will give the best result. Whcn the unit js set ;n fasi forward modc, the amount of f.;ction will greatly be reduced and will become l0 to 20 grans. Check to sce whether this is proper, if not, rcadjust coil spring and spring rtainer washc. See figure I I (b) at left) 7. ADJUSTMENT OF TAPE H

47、EAD A vertical azimuth alignment of tape head is the only adjustment that can be made at the field of service. To align tape head, play 8,000 cycles recordcd on an AmPx standard alignment tape. Rotate th azimuth al;gnment sc.ew until a maximum playback level through the small hole which is positione

48、d on the shield cover of the tape head assembly. -9- .t, ; Fig. ll R(/.Ly Hli Fig. 12 :ir. =.,. tllADJUSTMENT OF AMPLIFIER r. ADJUSTMENT OF RECORDING BIAS FREQUENCY Rccording/crasing bias frcquctrcy was set at 90 KC plus or m;nus 5 KC before sh;pment. It is decided by inductance otthc oscillato. coit lpart * l7-L,) and its resonant capac;tor (part f C-17). To mcasu.e recordiDg bias frcquency, insert a l0 or 100 ohm resisto. ;n scrics to the .cco.d/play head and coDnect verti