Sharp GF-777H User manual

SHARP
SERVICE
MANUAL
ATSM881115RCS
GF-777H
GF-777E
In the interests of user-safety the set should be
restored to its original condition and only parts
identical to those specified be used.
PHOTO: GF-777H
FEATURES
Multi-Amp 3-Way 6-Speaker System Massive 90W PMPO
Dynamic Super Woofer Sound
16cm (6%"") Woofer with Rigid Speaker Ring
Horn Tweeter for Clear, Crisp Highs
Two Decks Side by Side, for Versatile Record/Playback
Soft-Touch Cassette Controls
Brilliant Metal Tape Sound
APLD (Auto Program Locate Device)
Sharp Super Noise Reduction System
INDEX TO CONTENTS
SPECIFIGATIONS, qos st oe cypress EB epee coals «ARR 6 gstet R amepegs Cee eee see eee 2
POWER SUPPLY/AG-SUPPLY. VOLTAGE.SELECTOR, wo:.:0.00 ctecesegure cence w canes 2
NAMES OF PARTS a isdseercveSpeiocoyeptasicss) oy tyecaj can Rhee dceelshces Se Spneysbaqnpe wien decd Spader 3,4
DISASSEMBLY ........ 1G Dien Ot Bmaeta Kae Cm oeghs se We Te Dee elame ee 4~7
BLOCK. DIAGRAM. a c.cccseccsberamesremeannn cewenceuot ee weuaseoaguines 8,9
MECHANICAL. ADJUSTMENT sacncacce cia caae cee cane e cn deen ene nee ns 10
ELECTRICAL ADJUSTMENT oc cccacccsedandaden ines wee eneeeedaae a 11 ~16
NOTES ON SCHEMATIC: DIAGRAM, 2. ooo: 20s ciuiaeeanae cameee maamerdmanc aware 17
SERVICING OF LEG-LESS TYPE RESISTORS AND CAPACITORS ......... 17,18
SCHEMATIC DIAGRAM) «.c5sc0ica.eeswevis vieeee ee Getions ees 19, 20, 23, 24
WIRING SIDE OF PRINTED WIRING BOARD .................. 21,22,25 ~29
CABINET EXPLODED VIEW ca. .000 0 0tihate teener. Sasserln. me Laaosio cael 30 ~ 32
MECHANISM EXPLODED: TOP VIEW ... ..e¢cin oc. teu aide wagation «.aeum Dee ds 33
MECHANISM EXPLODED BUTTOM VIEW *. aiiceccs deaiwen Oo setae se aarties 34
DIAL CORDS TRINGING ic ajsccise tes a: 0 se a: PROMS cin, SEES AOR, IE ses Ole CNS 35
AG SUPPLY: CORID) aco: cctnsy-r steps: appeal oa wo OOS: AAS PENNS wei". te oaibecs lta 35
EQUIVALENT CIRCUIT OF INTEGRATED CIRCUIT .................... 36, 37
PACKING METHOD (GE-777E Only) ose: ccniseewennees snceeeeobe wd ee: oak 38
REPLACEMENT PARTS: LIST weiss nace sescyey eect sa sea oaunate emi erage os win 39 ~ Back
SHARP
CORPORATION
Osaka,
JAPAN
GF-777H

FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS UNIT,
PLEASE REFER TO THE OPERATION MANUAL
SPECIFICATIONS
GENERAL
TAPE
RECORDER/PLAYER
Power
source:
AC
110/220/240V
,
50/60Hz
Tape:
Philips-type
compact
cassette
tape
DC 15V (UM/SUM-1, R-20, HP-2, Frequency response: 30Hz to 18000Hz (Metal tape)
or “D’’ battery x 10, or external 30Hz to 17000Hz (CrO, tape)
DC supply) 30Hz to 14000Hz (normal tape)
Speakers:
Super
Woofer;
16cm
(6-1/2")
x2
S/N
ratio:
56dB
(SNRS:
ON,
METAL
TAPE)
Woofer; 16cm (6-1/2") x 2 Wow and flutter (DIN 45511):
Tweeter; Horn type x 2 0.14%
Output
power:
(GF-777H)
(DIN
45324)
Input
sensitivity
and
input
impedance:
MPO 28W, AC supply operation, Ext. Mic; 600 ohms
with four amplifiers Mixing mic; 600 ohms
RMS 24W, DC supply operation, Line in; 0.1V/100k ohms
with four amplifiers Output level and loaded impedance:
(GF-777E)
MPO
45W,
AC
supply
operation,
Headphones;
8
ohms
to
25
ohms
with
four
amplifiers
External
speaker;
4
ohms
to
8
ohms
RMS
24W,
DC
supply
operation,
Line
out;
0.6V/47k
ohms
with four amplifiers
Semiconductors:
17-IC’s
RADIO
52-Transistors Frequency range: LW; 150 —285kHz
1-FET
MW;
520
—
1620kHz
1-SCR
SW;
5,95
—
18MHz
61-Diodes
FM;
87,6
—
108MHz
11-LED’s
Dimensions: Width; 752mm
Depth; 166mm
Height; 379mm
Weight (without batteries): 12.2kg
POWER SUPPLY
The GF-777H/E Unit will operate on an AC mains supply of
110 Volts, 220 Volts, or 240 Volts of 50Hz or 6OHz. For
portable use it will operate on its internal batteries, or from an
external 15 Volts DC supply (with an adaptor).
AC
SUPPLY
VOLTAGE
ADJUSTMENT
The Voltage Selector setting should be checked to see that it
conforms to the local AC supply voltage. This must be done
before plugging in to the AC supply. Adjustment is made by
turning the adjusting screw in either direction with a minus
headed screwdriver until reading of Selector matches the local
AC supply voltage.
Caution:
Use this unit only on the specified voltages, otherwise
damage, fire, or accidents may be caused. SHARP cannot
accept responsibility for any damage resulting from the use
of this unit on unspecified voltages.

aOBWN =
16.
17.
18.
19.
20.
32.
33.
34.
35.
36.
37.
38.
. Deck 1: Cassette Compartment
. Deck 2: Cassette Compartment
. Super Woofer Sound Control (Left)
. Super Woofer Sound Control (Right)
. Tweeter (Left)
Deck 1: Cassette Ejection Key
Deck 1: Playback Key
Deck 1: Stop Key
Deck 1: Rewind/Review Key
Deck 1: Cut Key
Deck 2: Tape Counter
Deck 2: Tape Counter Reset Button
—
SOMND
NAMES OF PARTS
. Woofer (Left)
. Super Woofer (Left)
. Deck 1: Monitoring Socket
Mixing Microphone Socket
Headphones Socket
11.
12.
13.
14.
15.
Super Woofer (Right)
Woofer (Right)
Tweeter (Right)
Built-in Microphone For Left Channel
Recording
Built-in Microphone For Right Channel
_Recording
Double
Cassette
2A:
22.
23.
24.
25;
Stereo Recording Level Control (Left)
Stereo Recording Level Control (Right)
Recording Mode Switch
Dubbing Switch
VU Meter/Battery Indicator
7 839 4 10
Figure 3-1
Were
c
uble
‘cassette
12
Deck 1: Fast Forward Wind/Cue Key 26. Deck 2: Playback Key
Deck 1: Pause Key
Deck 2: Editing Key
Deck 2: Pause Key
Deck 2: Record Key
19 20 21 22 23 24 25 26
Figure 3-2
27. Deck 2: Stop Key
28. Deck 2: Rewind/Review Key
29. Deck 2: Cut Key
30. Deck 2: Fast Forward Wind/Cue Key
31. Deck 2: Ejection Key
27° «28 29
39. VU/Meter/Tuning Indicator
40. Deck 1: Tape Selector Switch
41. Deck 2: Tape Selector Switch
42. SNRS Switch
43. Meter Selector/Dial Light Switch
44. FM Mode/FM Muting Switch
45. Wave Band Selector Switch
46. Radio Echo Indicator
47. Dubbing Indicator
48. FM Stereo Broadcast Indicator
49, Fine Tuning Control
50. Tuning Control
51. APLD Input Buttons
ave
on
36 37 40 41
42 44 45
Figure 3-3
=

52. APLD Indicators 56. Echo Control 60. Treble Tone Control
53. Function Switch 57. Microphone Fader Control 61. Channel Balance Control
54. Deck Mode Selector Switch 58. Tape Fading Control 62. Cutput Volume Control!
55. Mixing Switch 59. Bass Tone Control 63. Loudness Switch
Figure 4-1
64. Power Switch 70. Grounding Terminal 76. Battery Compartment
65. Power Indicator 71. Remote Start/Stop Control Socket 77. Beat Interference Cancelling Switch
66. FM Antenna Terminals 72. External Microphone Socket 78. External Super Woofer Sockets
67. Input Selector Switch 73. AC Supply Voltage Selector 79. External Main Speaker Sockets
68. Line Output Sockets 74. 15 Volt DC Terminal 80. Telescopic Antenna
69. Record Player Input and 75. AC Supply Input Terminal
Line Input Sockets
68 67 6970 72 71 80
73 «7574 76 79 7778
Figure 4-2
DISASSEMBLY
Caution:
Prior to the disassembly, be sure to draw the AC mains lead cassette compartment with a cassette tape.
plug from the AC mains socket of the unit and to unload the
= Removal of Front Cabinet and Back Cabinet
1.
Remove
one
tuning
control
knob,
one
fine
tuning
control
knob,
one
volume
control
knob,
two
record
control
knobs,
six
other
control
knobs,
one
deck
mode
selector
knob,
one
wave
band
selector
knob
and
other
ten
selector
knobs.
Then
remove
two
punching
metals
and
two
super
woofer
sound
control
knobs.
See
Fig.
4-3.
2.
Remove
nine
screws
at
the
front
cabinet
and
back
cabinet.
See
Fig.
5-1.
3.
Open
the
back
cabinet,
and
withdraw
two
antenna
lead
tips
a
I
(white,
black)
from
the
cabinet
inside.
See
Fig.
5-2.
ee
ee
i
4.
Remove
one
socket
from
the
power
P.W.B.
located
at
the
——
a
lower
of
the
back
cabinet.
See
Fig.
5-3.
Figure 4-3
=f

Figure 5-2
Removal of Main Frame
Remove
five
sockets
at
the
power
amplifier
P.W.B.
See
Fig.
5-4.
Remove
three
screws
at
the
main
frame,
two
screws
at
the
power
switch
holder,
one
screw
at
the
power
amplifier
P.W.B.,
three
screws
at
the
headphone/microphone
P.W.B.
and
one
socket
at
the
echo
P.W.B.
Then
hold
the
main
frame
up
to
remove.
See
Fig.
5-5.
Figure 5-1
Figure 5-5
alias
Figure 5-3

EZ Removal of Mechanism Block
1. Remove three sockets at the mechanism P.W.B., two
sockets at the record/playback P.W.B. and one socket at the
bias current P.W.B. See Fig. 6-1 and 6-2.
2. Detach the tape counter drive belt from the tape take-up
reel disk. Remove four screws at the mechanism block, and
shift the mechanism block forwards and detach. See
Fig. 6-3.
Figure 6-1
Figure 6-2 Figure 6-3
= Removal of Tuner Frame
1.
Remove
one
socket
at
the
tuner
P.W.B.
See
Fig.
6-4.
2.
Loosen
three
tabs
securing
the
dial
scale
plate,
and
detach
the
plate
while
shifting
it
down.
See
Fig.
6-5.
3.
Remove
three
screws
at
the
tuner
frame,
and
detach
the
frame
while
shifting
it
to
right.
See
Fig.
6-6.
me
Wo
RARBERBAE
ao.
Amar
weeeeeter
ef
-
.
Wa
«
a
Figure 6-5
= Removal of Power Amplifier P.W.B.
1. Remove one screw and two tabs at the super woofer sound
control P.W.B., and one screw at the power amplifier
P.W.B. Then hold up the power amplifier P.W.B. to remove.
See Fig. 6-7.
Figure 6-7

Figure 7-1
Figure
7-2
Figure
7-3
= Removal of Record/Playback P.W.B.
1. Remove two screws at the APLD P.W.B. and four tabs at
the indicator P.W.B. holder. See Fig. 7-1.
2.
Remove
three
tabs
at
the
bias
current
P.W.B.
See
Fig.
7-2.
3. Remove two screws at the input/output terminal board. See
Fig. 7-1.
4. Remove one nut and one screw at the record/playback
P.W.B. See Fig. 7-3.
5. Withdraw the record/playback P.W.B., and remove two
screws and two tabs at the angle supporting the volume
P.W.B. See Fig. 7-4.
6. Remove two tabs at the APLD switch P.W.B. Thus it is
Figure
7-4
possible
to
detach
the
record/playback
P.W.B.
and
volume
P.W.B. from the main frame. See Fig. 7-4.
= Removal of Power P.W.B.
1. Remove four screws at the power transformer and two
screws at the AC socket. Then detach the power P.W.B. See
Fig. 7-5.
Figure 7-5

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MECHANICAL ADJUSTMENT
Pinch Roller Pressure Check
1) Set the unit in play mode.
2) Push a tension gauge (0 to 500 g) into the pinch roller lever
to make the pinch roller off the capstan, and release the
gauge applied force gently so that the pinch roller sets back
to the capstan (the pinch roller again rotates).
At the time, the tension gauge reading must be 300 to
380 g.
3) If the step 2) is unsatisfied, bend the pinch roller pressure
spring properly, or renew it.
=
TORQUE
CHECK
AT
PLAY,
FAST
FORWARD
AND
REWIND
MODES
Put
a
torque
meter
cassette
in
the
cassette
compartment
of
the
set,
and
see
that
the
measured
torque
in
each
mode
is
normal
as follows:
Mode
Torque
meter
cassette
|
Measured
torque
Playback
TW-2111
35
~
60
gram-cm
Fast-forward
TW-2231
90
~
135
gram-cm
TW-2231
90
~
135
gram-cm
Tw-2231
TwW-2111
Figure
10-2
=
GAP
CHECK
OF
PINCH
ROLLER
LEVER
©
Place the set in play mode, and see that the pinch roller lever
moves to create the gaps (A), (B) and © as shown in Fig. 10-3.
Play Release Lever
Pinch Roller Lever
:
Figure
10-3
Tape
Speed
Adjustment
1) Reproduce a test tape (TEAC, MTT—111, 3 kHz-
prerecorded) — the playback must be at the middle of the
tape but not at either the beginning or the end.
2) Connect a wow/flutter meter, across a 100K ohm resistor,
to the line output socket.
3) Adjust the semi-variable resistor, using a plastic screwdriver
via the hole at the motor unit bottom, so that the playback
frequency will be 2,985 to 3,015 Hz (Deck 1) and 2,970 to
3,000 Hz (Deck 2).
Note:
The motor pulley, flywheel drive belt, flywheel, take-up
pulley, take-up idler and take-up turntable, etc. must be free
of any contamination.
Figure 10-4
~10—