Sharp WF-971T User manual

SHARP
WF-9711
SERVICE MANUAL
No. SX674WF971TBK
WF-971 T(BK)
• Inthe interests ofuser-safety theset should be restored toits
original condition and only parts identical to those specified
should be used.
CONTENTS
Page
SPECIFICATIONS 2
NAMES OF PARTS 3
FITTING OF DIAL POINTER 3
DISASSEMBLY 4
REMOVING AND REINSTALLING THE MAIN PARTS 5
ADJUSTMENT 6
SCHEMATIC DIAGRAM / WIRING SIDE OF
PW.BOARD 8
NOTES ON SCHEMATIC DIAGRAM 12
TYPES OF TRANSISTOR AND LED 12
REPLACEMENT PARTS LIST / EXPLODED VIEW
SHARP CORPORATION

v,v ,r~~I' I 1/
FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS UNIT, PLEASE REFER
TO THE OPERATION MANUAL. - -
> .
.../.. '- .. ,.; .... ,.'
SPECIFICATIONS
Specifications for this model are subjectto change without
prior notice.
10 W
3 ohms (surround speaker
6 ohms)
Width; 195 mm (7-11/16")
Height; 217 mm (8-9/16")
Depth; 189 mm (7-1/2")
1.2 kg (2.6 Ibs.)/each
12 em (4-3/4") free-edge
speaker x2
5 em (2") surround speaker x2
Wow and
flutter:
Motor:
Bias
system:
Erase system:
• Tape recorder section
Frequency response: .60 - 12,000·.HZ (Normai tape)
Signatiiioise rafto: 40 dB (TAPE 1, recording/
playback)
55 dB (TAPE 2, playback)
0.15 % (DiN 45 511)
DC 12 V electric governor
AC bias
Magnet erase
Dimensions:
Weight:
Maximum
input
power:
Impedance:
• Speaker section
Speakers:
FM; 64 - 108 MHz
MW; 526.5 - 1,606.5 kHz
LW; 148.5 -283.5 kHz
AC 220-230 V,50 Hz
DC 12 V ["D" size (UM/SUM-1,
R20 or HP-2) battery x80r
external DC 12Vj
30 W
PMPO; 60 W (30 W + 30 W)
(AC operation)
MPO
(M~.); ".
20.W (10 W +10 W)
(AC operatidn) i
RMS; 10 W (5 W + 5 W)
(DC operation, DIN 45 324)
Mixing microphone; 600 ohms
CD/LINE; 350 mV/47 kohms
Headphones; 16-50 ohms
(recommended; 32 ohms)
Width; 300 mm (11-13/16")
Height; 217 mm (8-9/16")
Depth; 186 mm (7-3/8")
2.9.kg (6.4 lbs.) without bat-
terieS' ;" ,
• General
Power source:
Output terminal:
Power consumption:
Output power:
Dimensions:
Input terminal:
Weight:
• Radio section
Frequency range:
-2-

33
..,g
35
"i' ~.-\)
),::-:~'J,-,_.,: __ 'i ;. ,,:.,j :::,- _. ,', •. :nn
16-171819~0 ~1 ~-223~4-2526-- -,
1_,TAPE.1 Ilr TAPE{2:"" 1
I HJ"-'. " • i 'c,,",.' "' j - I
,28,1,29 .,30: i~1 ""
N~MES:;OF- PARTS
1 2 34561
1. Bxtra Bass Control: X·BASS
2. Graphic Equ~lizer Controls
3. FM,JStereo,lndicator
4.' 'Pc3wer Indicator,
5. (tAPE 2j Play Direction Indicators
6. Function Selector Switch
7. iMQlume ,Control
8, ,P.u,b.bing :Speed/Built-in Microphone/FM Mode
Switch
9. Bullt~in Mlcropho'ne
10. Tuning C9ntrol ,I
11. Band ,S~,ector SWitcl;l
12; Headphone So~ket
13;'Mixing Microphi:>ne Socket
14. Surround SWit~h
15."(tAPE:1fcassetie Com~artment·
16; (fAPE ljRecord B~llon: •
17., (TAPE1)'Play,Sulldn:...., I '
,,'!',
1S:''tTAPE,1) Rewind Bullon:,,.. ...
."n:,··c. i .'.' .' .:'" - ,.- ...... -
1'9. (TAPE 1) Fast Forward Bullon: ~~
20. (TAPE 1) Stop/Eject Bullon: .~
21. (TAPE 1) Pause Bullon:lin,
22. (TAPE 2) Reverse Mode SWitch:~~",_ <=>
23. (TAPE 2) Play Button: ... ~ .
24. (TAPE 2) Fast Wind Bullons: ~_
25. (TAPE 2) Stop/Ejec!sUllon: .~.
26. (TAPE 2) Direction Switch: .......
27. (TAPE 2) ceeeette ComparbTIenL ..
28•.FM'Telescopic' Rod Aerial
29. CD/L.in~ I.nputSockets
30. Beat caneet Switch
31. Surround, spe~ker'iei'minaIS
32. Speaker Terminals
33 A6 Power. Input Socket
3,4., ,?-q, Pow~r Input!g'ocket
35.' Battery Compartment
36. Surround Speaker'
37: j F'lin Range Speaker
38.Sass' hertex Duct '
as:L", S#~ak~r 'Relea's~ lever
40. Speaker Wir~ "
Main PWB
Screw(B06)
1U1-ft-~~;::&'
ea xamm
Tape
Mechanism
'II!
FITTINGOF DIALPOIN,.ER '. "
Di~i PO,inte;~(203),,, "~II ,':,,"" _ .• '
I ,,:,;,,'," ,IIO""I'p'o'I'nt
", , "F7¢="I,
ialPointer (203
1. Remove themainPWB.Allachthedialpointeras shown arrow
®onthefrontcabinet, puttingit'intothesection indicated by
arrow®.Insertit betweenthearrows©.
2.InstallthemainPWB in.tb,e frontcabinetand secure"il withthe
two screws.' , ,,' '! ,';, I • ,.~"~, .1,,;;:-
3.Turnthedial drum inthe direction indicated by arrow@. Set
the dial pointerto point "0", and then make the rest of the
adjustments.
F'igure :3
-3-

WF·971T DISASSEMBLY
Front
Cabinet
Front
Cabinet
(A2)x2
03 x10mm
~~~
t(A7) xl
//--=;;dR-c-r- Main
PWB
(E2) x1
Figure 4-2
(M) x1
03 x20mm Rear
Cabinet
Figure 4-1
(D1)x2
03x8mm
Front Cabinet Main Nat
PWBVolume
PWB (B1) xt
Washer
LED PWB
Graphic
Equalizer
PWB
Surround PWB
Open
~ Casselle
Holder
(Lefl/Right)
(C1) x4
esxarrm
Caution on Disassembly
Follow the below-mentioned notes when disassembling
the unit and reassembling it, to keep it safe and ensure
excellent performance:
1. Take cassette tape out of the unil.
2. Be sure to remove the powersupply plug from fhe wall
outlet before starting todisassemblethe unit and remove
the batteries from the unil.
3. Take off nylon bands or wire holders where
they need
be removed when disassemblingthe unil. Afterservicing
the unit, besure to rearrangethe leads where they were
before disassembling.
4. Take sufficient care on static electricity of integrated
circuits and other circuits when servicing.
SPEAKER
MAIN UNIT
STEP REMOVAL
PROCEDURE
FIGURE
1
Front Cabinet! 1. Battery Compartment
Rear Cabinet Lid ..................
(Al)xl 4-1
2. Screw............... (A2)x4
3. Screw............... (A3)xl
4. Screw...............
(M)xl
5. Screw............... (A5)x5
6. Socke!.............. (A6)xl
7.Tip.................... (A7)xl
2MainPWBI 1. Knob................
(Bl)xl
4-2
VolumePWBI 2. Socket..............
(B2)x5
Surround PWB 3. Screw...............
(B3)x2
3
Graphic Equalizer
1.Screw............... (Cl )x4 4-2
PWB
4LED
PWB 1. Screw............... (01 )x2 4-2
5Tape
Mechanism 1. Openthe cassette holder
4-2
2. Screw............... (El )x5
3. Lug................... (E2)xl
6
Power PWB 1. Screw............... (Fl )xl 4-3
2. Bracket.............(F2)xl
STEP REMOVAL
PROCEDURE
FIGURE
1
Front Panel
1. Screw............... (G1)x4 4-4
2
Woofer 1. Screw............... (G2)x4 4-4
3
Surround 1.Screw............... (G3)x2 4-4
Woofer
Speaker Cord
Holde:...r __ ~_
Speaker
~r=''!CCord
0",-::'...-_Driver
(G1) x4
03x16mm
Power
Transeformer
SpeakerBox
Figure 4-4
Figure 4-3
-4-

WF~97:tT
:~';~:\-) ';':
''', t
C02.} x3
Special Screw
1'-TA:PE21
;,j- j
Playback
Head'-
tI TAPE'2 1 " '
.1
Pillch.Roller'
.. -- ,195f ,,,i). ,
Pinch Roller
Pawl" •..
...........
.,,, '(l)
:JI:T'APElf;!
(AI) ,,1·.
i, ,·,
..•. ,.0:'1
02x3mm, ,J ',-, ,,~'-,) hJ .'
·,·;CRecord/Playback
-Head
. <_1.'-,.'; I, ',1
Figure 5-1
Figure 5-2
Motor
Figure 5-4
.Figure
5"'3
i.: i
, ):'.: ~l
iI~:d'J~)",'i');) ;".
(81-)-1<1-
02x6mm
Hook
~A,2) ,,:;....'. . ,
WW
·::: ,- "
",. ,
t
[TAPE 1I 'in
Pinch·Rolier
- @ " . (Cl).·.·.· .
",,' "'j ',J
PinchRoller
Pawl
REW/ FF
Belt REW /FF
(E3)xl ClutchAss'y
I TAPE 1I
Mater
,',"
ITAPE21
Frywheel
REW/ FF
Belt
(E3)
xl
REMOVING AND ~EINSr~LlING THE MAIN PARTS
TAPE MECHANISM SECTIOllj:J
Perform steps 1, 2 and 5 of the dis!lssembly""methbd to
remove the tape mechanism. (See page 4';) J:: 'i.""'1·I">:, '
':' -'. ;-:'; ':-l' ':~ -~:'" :1
How to removethe record Iplayback;playback
and-e-iaseheads (See Fig.5~1· and5~2.) ...
',I. Remove thif~crews! (,I\I}x~ pCS:;LtO' remove.the:recordi
i playbadffl6:ad. i ~'iL';)i]' .
,_ ... '_', __ .. ' .. _, _, '._ .. 1 .. _ ., _ .... _ ... ,I
,2.Rembv.em;e.. hQiqk~(A2P(2pts:;toW~rd the tef1terpositi~rl
; a.~;,~.~,o",,~}n; ~iq,)5,1. and then extia9t the erase head
.. upward. __ ..1_ _ . __ 1
'3. Remove thescrews :(Bl) x2 pcs., to remove the plaYbae~
'head. -;:;:)i'; :",;YT ::-;; ,',"<)
iNote:~::<';;:i'-:' ":'-,i,]::.; ):-1 ! ,1:1,>:')) ';: .,1i,:.:';, , .".
,I. The-playbaclc. hea~ of this m~pqi'.~i.s,m is supplied as
.;:finished product with
f1exiplE\;Pi!V,!;l,', Hi I
Before removing the flexible PWB,.:re"love the solder on
ithe switch. \.- ...- - ...... ",-- _..
2. After replacing the 'heads' lliiiJ'·ila.ri6r~ing the"iizirh~tJ1
~. "', -." '''', . ' t l .:. ':_.' '." ~ I
adjustment, be sure:t(j~applyscrewIQck:i'
How to remove the pinch ,roUetl
l(See,Fig. 15-3.)
il. Carefully bend the pinch rollerp,,"wl h,' the direction of the
.
arrow ®, and remove the pinch ron'er (C1 rand (C2)
upwards.
How to remove the motor (See Fig. 5-4.)
1. Remove the beit. ''liT:'!:
2..Remove the screws, (Dl) x4pcs., toremovelhe motor
bracket,,_', ,., :' ~h;;~'j:'i i~.:~' ,
3. Rem~v~' ik~'~crewsi (D2)JxJ3:pcs'iitcYramovethe motor.
, i,lJ..':)-,),I, ',.1 " .
Note:
When ffi,!untiqg themotor, pay attention to the m6t6rmount;
'ing ,argl~~;: ;'::'1' j":'1i; '",") !_~:' i- -;.,,;.
How to remove the belts (See Fig. 5-5.) ..." '.
'1. Remo~ethe"rriaiil b~lt (El) x1 pc:,aitHe lapefs1defro"l
. the motor pulle\C: .. ". ":". .
2. Remove the:ri1airibelt (E2).x:li pc.cat the tape 2 slde.from
therhotor'plilley.
'3. m;rhove the REW/FF belt,(Eii) 1<2. pcs., from the REW/FF
roller.
4:PUf on the beits in the reverse order of removal,
Note:
When putting on the belt, ascertain thatthe 5eitisnot twisted,
.and clean it.

WF-971T
MECHANISM SECTION
• Driving Force Check
ADJUSTMENT
TUNER SECTION
fL: Low-range frequency
fH: High-range frequency
Torque Meter Specified Value
Play: TW-2412 Tape 1: Over 50g
Tape 2: Over 60 9
• Torque Check
Torque Meter Specified
Value
Tape 1
Tape 2
Play: TW-2111 30 to 60 g.cm 30 to 60 g.cm
Fast forward: TW-2231 55 to 120 g.cm 80 to 135 g.cm
Rewind: TW-2231 55 to 120 g.cm 80 to 135 g.cm
• Head Azimuth
Test Tape Instrument Connection
MTT-114 Headphones Socket
(Load resistance: 32 ohms)
• Tape Speed (Normal only)
TestTape Adjusting Specified Instrument
Point Value
Connection
MTT-111 Tape 1.2: VR501 3,000 ± 60 Hz
Headphones
socket(Load
resistance:
32 ohms)
TAPE SECTION
Position of each switch or control
Volume control
Max
Beat cancel
A
Function/Power
Tape/Stand-by
Dubbing speed/Built-in Microphone OFF/Mic ON
• Bias Oscillation Frequency
Specified Value
Beat cancel
A: 100±4kHz
B: 94±4kHz
C: 104 ±4 kHz
• Playback Amplifier Sensitivity Check
TestTape Specified Value
Instrument Connection
MTT-118 1.3 V ± 3 dB Speaker terminal
(Load resistance: 3 ohms)
• AM IF/RF
Specified
Instrument
Test Stage
Value/Adjusting
Point
Connection
IF T3 Input: Antenna
Output: Pin 3 of IC2
MW Band fL: L6 Input: Antenna
Coverage fH: TCa Output:
MW Tracking fL (600 kHz): Headphones Socket
L3(MW)
(Load resistance:
fH (1,400 kHz): azohms)
TC7
LW Band fL(148.5kHz): L7
Coverage fH(283.5kHz): TC4
LW Tracking
fL: (LW)
fH : TC2
• FM IF/RF
Specified
Instrument
Test Stage
Value/Adjusting
Connection
Point
IF T1 Input: Antenna
Detection T2 Output: Pin17 of iC2
Band Coverage fL: L2 Input: Antenna
fH: TC6 Output:
Tracking fL (88.0 MHz): Headphones Socket
L1 (Load resistance:
fH (108.0 MHz): 320hms)
TC5
• VCO Frequency
Test Stage Specified Value
Instrument
Connection
VR1 76 kHz ± 200 Hz Pin 13 of IC2
-6-

JMAINPWB I
)
L4
LW ~
L3
~ MW
• -rC2@@I®I~5" .
.. ' TCa ,TC3@1(§J ILa
TG70 0 '." L.7eL-Ifi-rrIMi'lti\m---:'1
,., I ',' "TC4 r;:-, ...
TS'TC50 0 '"' i±lloili' f:\Y~~T~P]8JQ~fM\~
'fA~I~II~I:' ,.,~"'T.@".~, "'<§)-,
12 ®1 :1:;1; IC1 L6 '
"r-iQ2l' I' T1
~. fH fL
VR1' T2j (§J I ~ ~gV~~~~E
~ FM DETECTION IFM IFI
Ivcol fH fL
FM BAND
COVERAGEi
FM
TRACKING
IMAIN PWBI,
Figure 7-1 ADJUSrME~T POINTS
ITAPE SPEEDI
~
VR501
ICNP501 I
IC401
. j'/ .,
FigureNAoJUSTME;NT ,PQI~TS·.
-'7-

WF-971T
A
r-----------------------------------------
-
-
"
SW40'O
~1l
~~~~J~~~
SW401C
•
"
".
'"
STAND·BY
flAPE R1tB
'"
rc'b
WER O
RADIO
~~W-B,(
.W
0504, M010R CONTROl.
'"
;.J~
'00'
I()§-
".-
10K(B)
.~~
~JR
<:Joe
-
",
~o
POWERON/CD r-s
RADIO
STANO-8m-APE SW401A
FUNCTION
SW103A
FMMONOIFMSTEREO
"
0120
4.7150
R120
."
l103 R119
2.7mli
."
C119
41150 -a
~~~~
R157
'"
~;! ~~
R158
'<
'"
~§
"'
ud
"
05020503: SWITCHING
'"
470K
C117
0,015
(MLI
,.
"
"
1N4145
tat
'"'
,I>
1N4148
"
05 • 042
1~4.7150
!"'Coo
"
'"
'00
HI·SPEED DUBBING: ( )
NORMAL SPEED OTHER
"
SW10l RECORD/PLAYBACK
'"
1/50
,~
100110
SW101F F'~I' _F======:'J
p~?~Ab'l( ~
FMIF
112 CFl
~3 I~
~~1 I ~ ~
i;3E i HI- 2
- - ,I O?kll nci ,+-----.,-"---+---1-----'-+----""'--"
,,~
0.02
9~2
'"
•
silE~~
'" '"
"•
,
sYn
Bp1r1A
I-
I
~"'"' ~ IC1
MIX ~~.£J TA737BP
GNOr-- ~ vee FM FRONT END
R150
."
R151
."
MAIN PWB A1
I CNP10~
i
i
,
I
,
I
i
'"
Te7 ;
FMBANDPASS
FinER
BPF',
""
L·CH I@~-":;o;,
GDILINE I~j-~-;~f::t::::==:::;;~;;;:=========f::=====f================il
R-CK I~
wctot ,i
BUILT-IN
MICROPHONE
II
Jl01
MIXING
MICROPHONE
"
lN4148
i
'M ,
OOANTENNAI
y,
F
D
8
E
c
G
H
NOTES ON SCHEMATIC DIAGRAM can be found on page 12.
1 2 3 4 56
Figure 8 SCHEMATIC DIAGRAM (1/2)
-8-

r-'
F
-
-
-
-
-
."
JNTAOI.
--------,
rca
WF;'971Ji
"' "rce
ia
rtrr i)
'"
VO~TAG.E
~~.
'.VOLTAGE-,:,
hPE
~
"0.
FM ',,_ " MW
-,
13. a..v ,
rfii
Ii
,. 14' ri'I
15', '.:lV
L:!TC6 LS l:CS'.
16-, lV "
""
n, IH',
r'';<V FMBA"D MW .
•
'.'V'-
e'
COVERAGE
"1.av
•,. 00
,. at
ea u. .
'"
ea ,CW
,. ,. ,. m4CKING
" rc,
n, ".
LW!IAI'ID
COVERAGE
icect
~y. VOLTAG
';r
..•.•.....
,
!
-- - ,-
J403 '
,HEADPHON~
I
i
,
-------'
78:11 ,12 I

WF-971T
-------:-----------
l:L~
TAPEMECHANISM WH ,
at ,'!)""
,"
'"
EAASE(6B)
HERAD
""~
330HZl
VR253 c:
1kHz ll~
~;ij!
VR252 ffi §
''"' J
VR261
10kHz
CNS251
,
a
a
•
s
+'''*-+-''4 e
IGRAPHICEQUALIZERPWB-B I
CNS103
nc
CN5~
SW503
TAPE2
PCAY
M501
TAPE
MOTOR
AECDROIPLA YBACK(B6)
',",0
SWS02
TAPEl
""'"
SW501
TAPE2
MAIN
8
A
C
"
?
8
7
(246)
-------------------------------RO---------------.,------------
7 EB
(2~5)
f8
(246)
T601
POWgR
TRANSFORMER
p,
S0601
"~_ KCP~~~:PC'
O. 0AC220V 230V
t~ '"',
(232)
.~--...=---{o::::::::J---u---------u------------
BATTERIES
DC,2V['O'size(UMlSUM·l,
R20orHP·2jBATTEAY X 5]
o
o
SW601
VOLTAGESELECTOR
AC220V-240V ACt lQV-127V
COLOR TABLE
BR BROWN
AD ,EO
0,
RANGE
H YELLOW
BR
GREEN
at. BLUE
H VIOLET
GY GRAY
W,
WHITE
ax BLACK
PK PINK
o
F
H
E
G
23 4 56
Figure 10 WIRING SIDE OF P.W.BOARD (1/2)
-10-