Yamaha K1020 Service Manual

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,t^STEREO CASSETTE DECK
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I FRONT PANEL
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aIJITPORTANT NOTICE
This manual has becn providcd for the use of authorized Yamaha Retailers and their service personnel.It has been assumed that basic servicc proccdures inhcrant to the industry, and more specifically YamahaProducts, are alrcady known and understood by the users, and have thereforc not been rcstatcd.
WARNING: Failure to follow appropriate service and safety procedures whcn servicing this productmay result in personal iniury, dcstruction of expcnsivc components and failure of theproduct to perform as specificd. For thesc reasons, we advisc all Yamaha product ownersthat all servicc required should be performed by an authorizcd Yamaha Retailer or thedppointed rer vice reprerentativc.
IMPORTANT: The prescntation or salc of this manual to any individual or firm does not constituteauthorization, ccrtification, recognition of any applicable technical capabilitites, orestablish a principle agent relationship of any form.
Thc data provided is belicved to be accurate and applicable to the unit/s indicatcd on the covcr. Thercscarch, engineering, and scrvice departments of Yamaha are continually striving to improve Yamahaproducts. Modifications are, therefore, inevitable and changes in specification are subject to change withoutnotice or obliSation to retrofit. Should any discrepancy appcar to exist, please contact the distributorsServicc Division.
Static dischargcs can destroy experrsive components. Discharge any static electricity yourbody may have accumulated by grounding yourself to the ground buss in the unit (heavygauge black wires connect to this buss).
Turn the unit OFF during disassembly and parts replacement. Recheck all work beforeyou apply power to th€ unit.
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I CONTENTS
TOSERVICEPERSONEL ........1
REARPANELS... .....1
BLOCKDIAGRAM ......2
SPEC|F|CAT|ONS. ......3
INTERNALVIEW. ......3
DISASSEMBLYPROCEDURES . ..... 4-6
MECHANICALADJUSTMENTS. 7 -9
ELECTRICALADJUSTMENTS . ....9-11
LSI DATA TABLES 12
TIMINGCHART .......13
PRINTED CIRCUIT BOARD (Pattern Side) . . 14 - 17
wtRtNG .. .. .. . 18
fcBLocK ..19-21
SCHEMATICDIAGRAM .....22,23
PARTSLTST. .24-36
SINCEI87 
@YAMAHANIPPON GAKKI CO., LTD. HAMAMATSU, JAPAN2.5k 533 El @ Printed in Japan. 85 . I
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K-ro2()
I TO SERVICE PER,SONNET
Cntical Components I nformation.Components having special characteristics are marked and must be replaced with parts having specif ications equalto those originally installed.
Leakage Current Measurement (For l20V Model Onlv)When service has been completed, it is imperarive ihat yo,verify that all exposed conductive surfaces are properlyinsulated from supply circuits.
Meter impedance should be equivalent to 1 5O0 ohm shunreoby 0.1 5r F
Leakage current must not exceed 0.5mA.
Be sure to test for leakagewith the AC plug in tjoth polaIrres.
I REAR PANELS
U.S.A. & Canadian models
General model
British & Australian models
European model
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							K-|o20
T SPECIFICATIONS
Type4-track. 2-channel stereoI nput Sonsitivity I mpedanceLi ne40 mV/30 k-ohmsHeadR & P Heads: Combination, Pure Sendust withtriple-laminated coreErase Heads: lon-plating Ferrite, Double-gapOutput Level/Load I mpedanceLineHead ohonesChannel Separation (31 5O Hz)Cross Talk i125 Hzl
MotorsCapstan: DC Servo MotorReel: Flat torque DC MotorAssist: DC Motor
360 mV/47 k-ohms3.6 mW/8 ohms40 dB60 dB
Wow & FlutterNo more than +0.06% (W. Peak);No more than 0.03% (W. RMS)
Power SuppliosU.S. & Canadian ModelsEuropean ModelBritish & Australian ModelsGeneral Model
12OV AC,6OHZ22OV AC, 50HZ24OV AC,5OHZ1 1 0 I 120 I 220 1240V AC. 50/60H2Fast Wind TimeAbout 70 seconds/45 seconds(High Speed winding) (C-6O)
Frequency ResponseNormal tape (-2OdB)Chrome tape (-2OdB)Metal tape (-20d8)
Power Consumption28 watts
20 to 18.O00H2 t 3 dB20 to 20,000H2 + 3 dB20 to 23,000H2 t 3 dB
Dimensions{WxHxD}435 x 134 x 380 mm17I la x 5-1 14 x 15
Weight7.6 kg {16 lbs. 12 oz.}Signal to Noise RatioDolby oftDolby B onDolby C ondbx on
More than 59 dBMore than 67 dBMore than 75 dBMore than 95 dB
Specifications are subject to change without notice.
(u)......(c) ......
U.S.A. model
Canadian model
Harmonic DistortionNormal tapeChrome tapelvletal tape
Less than 0.5%Less than 0.5%Less than 0.8%
(A).......... Australian model(G).......... European model(B) ..... . British model(R1.......... General model
I I NTTNNAL VIEW
O PoWER TRANSFoRMERU.S.A. & Canadian models: GA68590European model : GA68600Australian & British models: GA68610General model: G468620
€) powEn clRcurr BoARD (1)
@ vnrru crRcurr BoARD (1)()dbx Circuit Board
@ Ootby Circuir Board
@cnpsreru MoroR(D neel MoroR
@ nssrsr MoroR
Op-COM lC: LM6402G-494
@powEa crRculr BoARD
3 
						

							K-ro2()
I DISASSEMBLY PR,OCEDURES
1. Adjustment of mechanism unit and replacement of
head parts.
a. Remove the cassette lid.
b. Remove 2 screws O in f ig. l and remove the blind
Plate.
c. Remove 4 screws @ in Fig. 1 and remove the front
pl ate.* In this state, the head can be adjusted and its parts
can be replaced.
Fis. 1
d. Remove 2 screws O in Fig. 2 and replace the record/
playback head.
e. Remove the screw @ in f ig. 2 and replace the erase
head.
f. Remove the E ring @ in f ig. 2 and replace the supply
side pinch roller.
g. Remove the E ring @ in f ig. 2 and replace the take-
up side pinch roller.
h. Bemove the washer O in f ig. 2 and replace the idler.
. Hsd wiring diagram{viewed from theu nderside)
Bemoval of mechanism unit
Remove 5 screws @ in f ig. 3 and remove the top
cover.
Remove the cassette lid.
c. Disconnect connectors #1
Fis.4.
Fis 3
through rfi, +7 and #8 in
. CONNECTOR WIRING
oA, G, B models.R model.U, C models BL
2.
d-
b.
d.R
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Cassette Lid
VoltageR. A, G, A mod.l! otrl
rr) RE lF6frE;Tfil \t, BE - 312
1E: G model-RE: A, B models
Fig.2 
						

							d.
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ii!ARemove 4 screws €) in f ig. 5 and pull out
mechanism unit gradually to the rear.
Replacement of capstan motor
Remove the mechanism unit.
Remove 4 screws @ in f lg. 6 and remove the back-
plate.
O WIRING OF MECHANISM UNIT
the 3.
a.
b.
Fig.5
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. Srtting flywhsl belt(viryed trom the rsr)
Fig.6
Sensor Circuit Board
Reel Motor - Lavel 
						

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c.Remove 3 screws
molor.
[) in Fig. 7 and replace the capstan
Fig.7
4. Replacement of reel motor
a. Remove the mechanism unit.
b. Remove 2 screws @ in Fig. 8 and remove the blind
Plate.
c. Remove the reel base as shown in Fig. 8.
 Note that coil springs of the supply reel and takeup
reel are different.
Supply side: Silver
Take-up side: Green
d. Remove the back plate (Refer to Fig. 6.)
e. Remove the washer @ in f ig. 8 and remove the
flywheel (take-up side).
K-ro20
Remove 2 screws @ and nuts @ in Fig. 9 and
remove the reel motor installation plate.
Remove 2 screws @ ln fig.9 and replace the reel
motor.
Reel Motor lnstallation Plate
Fig.9
5. Replacement of assist motor
a. Remove the top cover.
b. Remove the blind plate.
c. Remove 2 screws @ in f ig. 10 and remove the assist
motor installation plate.
d. Remove 2 screws @ in f ig. 10 and replacethe assist
motor.
Assist Motorlnstallation Plate
Assist Motor
Fis. l0
s.
6
Capstan Motor
Push the reel base to the rear and removethe ring.
Fig. I 
						

							K-ro20
I MECHANICAL ADJUSTMENTS
1. Before adjustment
o Since head magnetization, dust accumulations, etc.
are likely to introduce error in the various character-
istics, it is very important that the heads are properly
demagnetized and cleaned.
2. lnstruments required
. Head Gauge (M-300)
o Audio frequency oscillator
. Oscilloscope
. Mirror Cassette {MC-109C}
a Torque meter
o Wow/flutter meter
o D.C.V.M. (DC Voltagemeter)
. A.C.V.M. (AC Voltagemeter)
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Adlustm€ntat€mTapeTestPointInstrumentrequiredMode%H.l:iH:, lAdiustmenti natine I Remarks
1Check clear-ance betweentake-up sidepinch rollerand capstanshaft.
PAUSEFig. AMore than O.5
2Panch RollerTimingBFigI STOP lWith head baseI jpushed up,j icheck timing atI which pinch
I lrollers onI isuoolv side andI itake-up side] lcontact capstan
] Take-up side Pinc] roller should startI rotating first.
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lli timing ot bothlsides is samultane-]ous or supply sideprecedes, adj.ust
lment rs requrreo.
I
t--Height of re-cord/playbackh€ad and tapeguide
ig.o
A.C.V.M.Oscilloscope
t\, ir- t*tt(MC-109C)
-Trq*t*
(Cassette type)
Repeat adj ustmentin steps 3 to 6 andapply screw lockparnt upon comp-letion of adjust-
r9!!.Adjust by usingspacer as shown inFig. H.
f Ot.n t.t Ptorque, read thecenter of deflec-tron.
Headgauge L(M 3oo) I I
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Headgauge I lwithM300(M-3OO) I lblock placedI lverticallY on reI lcord/PlaybackI lhead, adjust soI lthat M 3OOI lgurg and blocki ]oecomes ParallelI l(Fis. E)-n.asffi
(M-300) i i
PB
Supply side ] Head gauge shouldoinch rotler I pass through smoothlVheight adiust- lwathout i.ts block con-ing screw (Fig. Jtacting pinch rollerc) lguide. (Fig. F)n.i. rtn aa- Eavback output of Ljusting screw ]and R is maximum(Fig. C) jand Phase differenceI lshould be minimumI I (Phase difference lessI lthan 60)
r lTape should move in1 lthe center of eraselhead smoothlYlCapstan (suppty side)
I lshould move smoothlv.
rvu,- Fr -T- --ffi?,c,
REWtorque, i ]35-559/cmtake up torque 1 i FF, REW torqueand back tensi- I more than 7oglcmon torque. Back tension: I Back tenslorl:lAdjustleaf ]5-1Og/cmspring (5 steps) ]i{Fie. t) I
4R eco rdlpl a Vback head tiltangle
5SupplV sidepinch rollerh eight
Fig.F
6Azimuth1OkHz,-10d8(MTT-1 14)
LINEOUT
7Check Posrtion of erasehead and tapemovement.
Check each
9Check FFand BEW tak€uP t im€s
AC-512712,22ac-60
I I l Normal; Less than u5I I secondsI I High speed: Less thanI I I ssseconds
Check speed ls€mr f xed varr I3OOO +.:Hzwhileplaying ar,leresrstorat J -rcjback 3kHz test the back of the Itape. lg_apstglt Motor. I(Fiq. J)
t0Tape speed3kHz,-10dB(MTT-111)
LINEOUTWow,/f luttermeter Frequency counter
PB
Wow/ F lutter
3ooo +., !uz
I Less than O.O5% ] Check wow/flutter(WRMS) while confirming
3kHz frequencywith wow/fluttermeter counter. 
						

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K-ro2()
Fig. B
Fig. c
t-rg. E
DifferencebeMeen A .nd BLess than l/2
*Make sure to reconfirm after sdjustment
Adjust by beoding head basecontscting part of supply sidepinch roller.
Confirm clearance and t;ming atteracljustment. There should be a clear-ance between lhe pinch arm andhead base on both supply and t6ke-up srdes.
Take-up Side Pinch Roller
-\
a
Tape
Supply Side Pinch RollerHeight Adjust Scrw
Capstan
Fig. A
Fig. D
Er€gHead
 ..Hesd F ix Screw
r^Tilt Angle Adjust Scrw
--
---A:@
 Be sura to tighten the head fixing scrfl securely, Be sureio apply scrw lck painr to each adjusiingscrry after sdjustment.
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Head GaugeM.300
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Head GaugeM-300
Adjust so that the sameclearance is obtained atthe upper and lwor parts.
E
;;;;;* Take-up side Pinch Floller
Fig. FFis. G 
						

							K-ro2()
 Use spacer to adjust the h8sd heighlFig. HFig. I
Capslsn Moto.
Fig. J
I ELECTRI CAL ADJUSTMENTS
O PLAYBACK ADJUSTMENTS* Make sure to use a new tape of I EC standards for a test
taDe.
Alignment tape
Normal TDK AC223 or YAMAHA NR 60
CrO2 TDK AC512 or YAMAHA CR 60
METAL TDK ACl12 or YAMAHA MR 60
o Proceed with the playback adjustments after having finished the mechanical adjustments.
] (dbx circuit I I {dbx circuit iI 1 board) 1-____1 I board) I
. RECORDING ADJUSTMENT
. Proceed with the recording adiustments after having finished the playback adjustments.
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i iDc.offset lrP2{B)-E i I I vR102(R) i
i-t-lFryb.ki^ r - i{tztzc l Lrrveou-f-eivnr---trl uRlon-L) -i 36otls--v --
I I | 1stsa,  i (Acvort/da I I vR1o4(R) I t-g.o+tdBv)
i I I 	oonwo/m/ I I rvteter) I lF_+ _+ _ __ f__t _ I
I s i etayuacr rrequency Mrr.3s6u I r-rr.re oui I ; 6nt i t-f---T;*;,*;
J i r.oonre conf irmation I {3t80 + 70ps1 i 1 1 lshoutd be wrthin specif i-response conTtrmatton (J tUU + /Ups, 1 i lshould be wtthin speciti-
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I i ] lcationinFieK
a ldbx rc 1 Tpl -rp2 D.C.V.M. 1 Srop 1 vRTOt i 15 t 2mV D.C.
I I (dbx circuit ] {dbx circuit
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[n.n=.;r lL^;F;;* faoa*. Appry a rkHz sine *;-]u*.tLr-r l*aaE rn-*,-i --l
Meter OUT signal from LINE lN so iVR5O4 {R) I (red} should Ir 1(+4.5dBl I rLiNE l-Au;it that LINE OUT voltase rs I ltisft. Ir ltno uott j li-,i ]fll$,., $J*,i,-iyJrlirtase is I lrisht ifF;k L*f oscillator f,ppty  r ri. rinu *u* fvnsor tr-r I ooe ,g-n, -iwrtn nllnsrEn -----l
Meter signal from LINE lN so 1VR502 (R) i(redl should FADER isdecreased L ll(OdB) 1 that LINE OUT voltage i tliStrt. and R segmentsi is 360mV (-gdBV). L around OdB shouldI 1 fade out almost simul-
* Use 360mV (-9dBV) for 0dB as the standard level of
this unit.
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8ek Teosion (5 iteps)at Playback mode
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l(OdB) 1 that LINE OUT voltage I llight. and R segmentsis 360mV {-gdBV}. ] around OdB should
 , I L fade out almost simur- i_l _ taneousty. I