Sharp GF-500 User manual

st-i~~~ SERVICE MANUAL :i
OUTSTANDING RECEPTION THE WORLD OVER
ATSM882109RCS
This Service Manual omits the descriptions about the adjustment
and block diagram of the Radio (High Frequency) Circuit, and for
their details, refer to the GF-54542 Service Manual (ATSM182013-
RCS) or GF-5454 Service Manual (ATSM382047RCT).
In the interests of user-safety the set should be
restored to its original condition and only parts
identical to those specified be used.
INDEX TO CONTENTS
SPECIFICATIONS 2
POWER SUPPLY/VOLT& .iiLi&i&i ’ : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2
DIAL CORD STRINGING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
NAMES OF CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
DISASSEMBLY
.*...............................,
4
AUDIO BLOCK DlAikil ’ : : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
CIRCUIT CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
APPS FLOW CHART .7,8
MECHANICAL ADJUSiM’Efi- ’ : : : : : : : : : : : : : : : : : : : : : : :‘: : : : : : : : : : . 9
CHECKING OF AUDIO (LOW FREQUENCY) CIRCUIT . . . . . . . . . . . . . . . . . . . .lO
SCHEMATIC DIAGRAM (l/Z), (Z/Z) . . . . . . . . . . . . . . . . . . . . . . . . . . 11,12,15
WIRING SIDE OF PRINTED WIRING BOARD (l/Z), (Z/Z) . . . . . . . . . . , . . . . . 13,14,16
SCHEMATIC DIAGRAM AND WIRING SIDE OF PRINTED WIRING BOARD AT
POWER SUPPLY SECTION OF GF-500 . . . . . . . . . . . . . . . . . . . . . . . . . . . _ .17
AC POWER SUPPLY CORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I7
NOTES ON SCHEMATIC DIAGRAM 18
DECK 1 MECHANISM EXPLODED Vii : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 19
DECK 2 MECHANISM EXPLODED VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
CABINET EXPLODED VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21,22
REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23% Back
SHARP CORPORATION
SHARP ELECTRONICS CORPORATION 1.

GENERAL
Power source:
(G F-500)
(G F-5002)
Speakers: Woofer;
Tweeter;
Output power:
(G F-500)
(GF-5002)
Semiconductors:
(G F-500)
(G F-5002)
FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS
UNIT, PLEASE REFER TO THE OPERAT.lON MANUAL.
SPECIFICATIONS
AC110 - 12Ol220 - 24OV, 50/60Hz
DC 12V (Ten “D” Size batteries or
external DC supply)
AC110 - 127/220 - 24OV, 50/60Hz
DC 12V (UM/SUM-1, R-20, HP-Z, or
battery x 8, “D” or external DC
supply)
12cm (4-3/4”) x 2
Ceramic type x 2
2.3 Watts per channel, minimum RMS,
at 3 ohms, from 100Hz to 20kHz with
no more than 10% Total harmonic dis-
tortion.
PMPO; 25W (12.5W +12.5W)
(AC Operation)
MPO;
2ow (low + low)
(AC Operation)
RMS; IOW
(5W +5W)
(DC Operation, 10% Distortion)
9-IC’s (Integrated Circuits) +6 Aux. IC’s
2 Transistors +21 Aux. Transistors
58-Diodes
1 O-LED’s
15-IC’S
23 Transistors
58-Diodes
IO-LED’s
Dimensions: Width; 582mm (22-7/g”)
Depth; 125mm (4-I 5/16”)
Height; 202mm (7-15/16”)
Weight (without batteries):
5.lkg (11.3 Ibs.)
TAPE RECORDER/PLAYER
Tape: Philips-type compact cassette tape
Frequency response: 40Hz to 16,OOOHz (Metal tape)
S/N ratio: Deck 2 50dB (Normal tape recording)
Deck 1 55dB (Playback)
Wow and flutter: 0.06% (WRMS)
Input impedance: External Mic; 600 ohms
Phone/Line in; 50K ohms/20K ohms
Output impedance: Headphones; 8 ohms to 32 ohms
External speaker; 3 ohms to 8 ohms
Line out;
0.55Vl50K ohms
RADIO
Frequency range: AM; 525kHz to
1,605kHz
SW1 ; 2.3MHz to 7.3MHz
SW2 ; 7.3MHz to 22MHz
FM; 87.6MHz to 108MHz
Specifications for this model are
orior notice.
POWER SUPPLY
The GF-500Z Unit will operate on an AC power supply of The GF-500 Unit will operate on an AC power supply of 11 O-
110 -
127 Volts, or 220
- 240 Volts of 50Hz or 60Hz. For120 Volts, or 220
- 240 Volts of 50Hz or 60Hz. For portable
portable use it will operate on its internal batteries, or from an use it will operate on its internal batteries, or from an external
external 15 Volts DC supply (with an adaptor). 15 Volts DC supply (with an adaptor).
VOLTAGE SELECTION
Before operating the unit on mains, check the preset voltage.
If the voltage is different from your local vo!tage, adjust the
voltage as follows: Slide the AC power supply socket cover by
a little loosing screw to the visible indication of the side OF
your local voltage.
1.
2.
DIAL CORD STRINGING
Turn the drum fully clockwise, and set the cord in the
numerical order from 1 to 11 as shown in Figure 2-I.
Turn the tuning control knob driving shaft fully clockwise,
and adjust the dial pointer to come into “Marking-off Line”
position of the dial scale plate. See Figure 2-2.
Marking-off Line
Figure 2-2 Figure
2-I

1. Level Meter
2. Power On/Battery Indicator
3. APPS Indicator
4. APPS End-Pause indicator
5. Dubbing Indicator
6. FM Stereo Indicator
7. Tuning Control
8. Fine Tuning Control
9. Deck 2: Digital Tape Counter
IO. Tape Counter Reset Button
11. Band Selector
12. Built-in Microphone (Right Channel)
13. Deck 2: Cassette Compartment
14. Deck 1 : Cassette Compartment
15. Built-in Microphone (Left Channel)
16. Deck 1: Eject Button
17. Deck 1: Play Button
18. Deck 1: Stop Button
19. Deck 1: Rewind/Reverse APSS Button
29. Deck 1: Fast Forward/Forward APSS
Button
2 1. Deck 1: Pause Button
22. Dubbing Start Button
23. Deck 2: Eject Button
24. Deck 2: Record Button
25. Deck 2: Play Button
26. Deck 2: Stop Button
27. Deck 2: Rewind/Review Button
28. Deck 2: Fast Forward/Cue Button
29. Deck 2: Pause Button
30. Power Switch
31. Function Selector Switch
32. FM Mode Selactor
33. Deck 2: Tape Selector Switch
34. Deck 2: Record Muting Switch
35. Dubbing Switch
36. Dubbing Speed Selector Switch
37. Tone Control
38. Balance Control
39. Volume Control
49. APPS Set/Clear Switch
41. Headphones Socket
42. FM/SW Telescopic Rod Antenna
43. External DC Power Supply Socket
44. AC Power Supply Socket
45. External Speaker Sockets
46. Beat Cancel Switch
47. Line Output Sockets
48. External Microphone Sockets
49. Input Selector Switch
50. Line Ihput/Phono Input Sockets
51. Earth Terminal
52. Battery Compartment
NAMES OF CONTROLS
Figure 3-1
Figure 3-2
42
4344
52 51 50 49 48 47 46
45
Figure 3-3
-..3-

DISASSEMBLY
Caution:
Prior to the disassembly, be sure to draw the AC power supply
lead plug from the AC power supply socket of the unit and to
unload the cassette compartment with a cassette tape and the
battery compartment with batteries.
Figure 4-1
m Removal of Front Cabinet (See Figs. 4-1,4-2 and 4-3)
1. Pull out one tuning control knob one fine tuning control
knob and three control knobs (volume, balance and tone),
all at the front surface of the unit.
2. Push the eject button to open the cassette compartment.
3. Remove nine screws from the front cabinet and back
cabinet: one screw of the nine is found in the battery
compartment.
4. Disconnect two speaker sockets and one earth tip.
a Removal of Mechanism Block (See Fig. 4-4)
1. Remove three screws from the mechanism block and the
drive belt from the tape counter.
2. Disconnect four sockets and detach the mechanism block.
a Removal of Main P.W.B. (See Fig. 4-5)
1. Remove two screws from the main P.W.B. and pull the
P.W.B. forwards.
2. Disconnect two sockets and pull one tip out, then detach
the P.W.B.
3. If necessary, it is recommended to detach the indicator
P.W.B. from the tuner frame.
q Removal of Tuner Frame (See Fig. 4-6)
1. Remove three screws from the tuner frame.
2. Pull out one tip and separate the tuner from the back
cabinet.
Figure 4-2
Figure 4-3
Figure 44
Figure 4-5
Figure 4-6
-4-

zl-
I I I
a
5
"
I I I
--+-t--l-
I I I
I I I
I
-- i
------.---_------ _____
----T
.-------
j& 211
Figure 5 BLOCK DIAGRAM
-5-

-.--...- ---.---..--.-
CIHCU17
It is possible to select either normal tape speed or high tape
speed when you perform dubbing from the deck 1 to the deck
2 and the high speed is twice as fast as the normal speed.
l Normal speed/high speed record selector circuit
Being provided at the deck 2, the integrated circuit IC202
works to select the normal speed mode or the high speed
mode: the frequency at the high speed is two times higher
than that at the normal speed. The IC202 also works to detect
whether a normal tape or a metal tape has been loaded in the
unit.
l Normal speed/high speed playback selector circuit
Being provided at the deck 1, the integrated circuit ICI05
works to select the normal speed mode or the high speed
mode: the frequency at the high speed is two times higher
than that at the normal speed. Here is also given proper
equalization for the signals of both speed modes. Further the
IC105 changes its constant according to whether a normal tape
or a metal tape has been loaded in the unit.
l Normal speed/high speed selector circuit
Change of the motor’s rotational speed results in a changeover
between the tape normal speed and high speed modes. The
electronic switch is used to act on the motor control circuits
of the deck 1 and deck 2 at a time as their speeds are changed.
Fig. 6-2 shows how the circuit works to get the unit in the
high speed mode, whose expression is made with use of the
mechanical switch instead of the electronic switch.
APPS (Automatic Program Pause System)
The existing APSS, as you know, is to automatically detect an
end of the program when the unit is in fast forward or rewind
mode and then to return it to play mode. The APPS employed
for the GF-SOOH/E is something new which is based on the
same ideas as with such APSS, and it is activated not only
when the unit is in play mode (at the deck 1 only) but also
when it is in dubbing mode (from the deck 1 to the deck 2).
In the dubbing mode (either at normal speed or at high speed),
as soon as an end of the program is detected by the APSS in
the deck 1, the APPS works to stop the motor circuits of both
decks 1 and 2 simultaneously -that is, motions of the deck 1
and deck 2 are stopped just at a time.
Therefore, the deck 1 has two automatic controls - APSS and
APPS, that is, it is controlled by the APSS when it is in play
mode (with the deck 2 in stop mode) and by the APPS when it
is in dubbing mode.
The two controls APSS and APPS are differentiated by the
following:
l Difference in gain and frequency characteristic between
APSS and APPS.
l Difference in program detect time between APSS and
APPS.
These differences are due to that the tape speed is different
according to whether the unit is in play mode or dubbing
mode, and according to these, the electronic switch selects the
APSS or APPS to get it in action.
CUNS~I KUCTION
Deck 1
Dubbing
Deck2
Wave length
Wavelength Wave length of
signalwavelength.
Figure 6-l
Deck 1 Motor
High
Speed
VR501
Q507
Motor Selector
Transistor
Deck 2
Speed
Play Switch
‘k”
Normal
High
Speed Speed
L
Deck 1 Playback Equalizer Selector
VR504
VR502 Deck 2 Record Equalizer Selector
M
Deck 2 Motor
Figure 6-2
Input
signal
Deck 1 Motor
Deck 2 Motor
Figure 6-3
-6-
/ fleolenoid 1
/ .
__-L-__Illl. ___ ---.-.
.._ _ .~_
,_.- . .._- . -. .~ . .I __., --~ .--- -- .--1----_--
- ._.._
_I--

APPS Flow Chart
I
/-- - - - - - -APPSallclear
APPS not settable
Deck 1 is in play mode?
The motor stops and the yellow indicator
- (D314) lights up. The red indicator is still
-
lit at the time.
(SW201)
is turned on?
Syncronous operation of
Deck 1 and Deck 2 is
(EL: With Deck 2 in stop or play mode, or
with the dubbing switch turned off)
I
The motor of Deck 1 gets
in a stop: Deck 2 alone can
be operated.
+
I
stopped. I
No. buttons (for play mode)

0The motor of Deck 1 starts again.
0 APSS set/clear switch is at “set”
position. (The indicators D302
and D314 are both put off).
I
L-e-- ---- ------------
Deck 1 is in APSS mode or in stop mode.
No.
I
Deck 1 is in APSS mode?
l APPS set/clear switch is at
@ The motor of Deck 2 is kept
--I
“set” position. in stop. (The yellow indica-
1
l The motor of Deck 1 starts again.
tar D314 keeps on lighting.)
(The red indicator D302 is put off.)
The motors of Deck 1 and Deck 2 start again
The motor of Deck 1 starts again.
The indicators D302 and D314 are put off at
The yellow indicator D314 is put off.
bl--
APPS all clear.

MECHANICAL ADJUSTMENT
PINCH ROLLER PRESSURE CHECK
1. Place the unit in PLAY mode.
2. Push the pinch roller, at the point shown in Fig. 9-1, by
using a tension gauge (500 gr.) so that it will come off the
capstan. Then, release the tension slowly until the pinch
roller hits the capstan again (i.e., the pinch roller is about to
rotate again). Then check the tension gauge is reading
350 gr. to 420 gr.
3. If the reading is outside the range of 350 gr. to 420 gr.
replace the pressure spring of the pinch roller.
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:
TAPE SPEED ADJUSTMENT (See Figs. 9-2 and 9-3)
Note:
The high speed operation has priority over the normal speed
operation, and so try to do the adjustment for the former first
and then for the latter.
For High Speed Operation
1. Connect a wow/flutter meter to the Line Output socket
across a 100K ohm resistor, and shortcircuit the deck 1
control terminal (TP503).
2. Play a test tape (TEAC, MTT-118, 1 kHz prerecorded) - at
its middle part but not at its start or end point.
3. Adjust the semi-variable resistors (VR501 for the deck 1
and VR502 for the deak 2) located on the deck 1 and deck
2 mechanism P.W. Boards, so that the output frequency is
1990 to 2010Hz for the deck 1 and 1980 to 2000Hz for
the deck 2.
For Normal Speed Operation:
1. Play a test tape (TEAC, Ml-T-1 11,3kHz prerecorded).
2. Adjust the semi-variable resistors (VR503 for the deck 1
and VR504 for the deck 2) located on the deck 1 and deck
2 mechanism P.W. Boards, so that the output frequency is
2985 to 3015Hz on the wow/flutter meter for both decks 1
and 2.
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
1. Make Connection of instruments as shown in Fig. 9-4.
2. Set the Dubbing switch SW201 to the off position and Tape
Selector switch SW105 to Normal position.
3. Adjust the head azimuth adjusting screw so that sine
waveform attains the maximum and the same phase in right
and left.
4. Even without using the oscilloscope, also adjust the head
azimuth adjusting screw so that outputs of both the right
and left channels attain the maximum and the same phase
in right and left.
Note:
For some heads, there may be a phase difference between
right and left channels when the output is made maximum.
In this case, adjust the head azimuth so that such phase
difference will be as small as possible while keeping the
output still maximum.
Pinch Roller
PressureSpring
Figure 9-l
Mode Torque meter
cassette Measured torque
Playback TW-2111
Fast-forward TW-2231
Rewind TW-223 1
35 - 60gram-cm
90 - 135 gram-cm
90 - 135 gram-cm
<--
Figure 9-2
Figure 9-3
E.V.: (Elecfronic Voltmeter)
TestTape
MT-r-1 14
Oscilloscope
E.V.
h’
J201 -G
assmallaspossible
/
I
Figure 9-4
-9-

CHECKING OF AUDIO CIRCUIT
BIAS OSCILLATOR FREQUENCY CHECK
1. Make connection of instruments as shown in Fig. IO-l.
2. Set the function selector switch to “tape” and the beat
cancel switch to “A”.
Record Mode
~ i [aad, k
Oscilloscope
3. Place the unit in record mode, and check that the
frequency counter reads 90 +5kHz.
Changing the beat cancel switch from “A” to “6” position,
see that the frequency counter reading changes by +4 -
6kHz from the previous value 90 25kHz: and with the beat
cancel switch set at “C” position, see that it changes by -3
- 5kHz from previous value 90 +5kHz.
Figure IO-I
PLAYBACK AMPLIFIER SENSITIVITY CHECK
1. Make connection of instruments as shown in Fig. 10-2.
2. Set the function selector switch to “tape”, the volume
control knob to “lO/max”, and the treble/bass tone control
knob to “center” position.
TestTape
MTT-118
3. Play a test tape (TEAC, MTT-118, IkHz, 250pWb/mm,
-1OdB prerecorded).
Head
4. See that the electronic voltmeter reads about 1.8V.
Figure IO-2
RECORD AMPLIFIER SENSITIVITY CHECK
Phono input 1.99
- 3.9mV
1. Using a CR oscillator, apply a signal of oscillation fre-
(-50 ?3dB, OdB = IV)
quency 1 kHz to each input socket of the unit. Line input 39.8
- 79mV
2. Check for the input voltage available when the level (-25
?3dB, OdB = IV)
indicator “OVU” lights up. See Table 10. External mic input 1.58 m
3.16mV
(-53 +3dB, OdB = 1V)
Table IO
For the radio (high frequency) Circuit adjustment, refer to the GF-54542 Service Manual
(ATSM182013RCS) or GF-5454 Service Manual (ATSM382047RCT).

PI01 2SAll43
Record Signal Microphone Signal
___) +B Line
APSS Signal Phono Signal
1 2 3 I 4 5 6
Figure 11 SCHE
-ll--
Q303.Q306 2SAlll5 F
Q304,0305 2X2603 F
,:
Playback SignalLine in Signal
H

I
7
8
9
10
11
12
I I
I I
I 1
0401 2SD471
L
IC204 IR2EOI lndlcator
DrlVe
9203 2X2603 F
I I I I
s w Q503,Q504 258562 C
B 9507,G5Oa
Q509,0510
2SC2603F
I
-
I
SCHEMATIC &RAM (l/Z)
8
910
I
11
12
-12-

I
C
I
F
I
L------
I
-1.
/
E
I
------ _____ -_
1 2
3 45
6
A
B
G
1
I Z I
3
I 4 I
3 I
tl I
Figure I.3 WIRING SIDE OF F
-13-
.~-. --
---.__-

P.VV.7BOARD
8
I
9
I
10
I
11
I 12
DE OF
(l/Z)
-14-

1
I
2
I
3
I
4
56
3 i
IC3 TA7313P PLL FM
? 3.4”
I
INPUT
I
II II I
I II I
1 I I 3 I 4 I 5 I 6
Figure 15 SCHEMATIC DlAGRAM (2/2)
-15-

1
1 2
I 3 4
I
5
-
6
---------7
I
L.------.
i 1
d
IC401
. .
?
2 4
;
Figure 1.6 WIRING SIDE OF P.W. BOARD (2/2)
5
6
-16-
IA
B
C
D
E
F
G
H
1

SCHEMATIC DIAGRAM AND WIRING SIDE OF PRlNTED WlRlNG BOARD AT POWER SUPPLY SECTION
OF GF-500
I
I
r_‘2i3 4 5 6
50602
M.oc
I
AC POWER SUPPLY CORD
QACCL0050AFOO (GF-5002)
QACCZ0051AFOO (GF-5002)
QACCK0050AFZZ (GFBOOZ)
QACCD005lAFOO (GF-500)
A
B
C
D
-
2
3456
I
-17-

NOTES ON SCHEMATIC DIAGRAM
Ref. No.
SW1 (A - F)
SW101 (A - J)
SW102 (A - D)
SW103 (A - D)
--
SW1 04
SW1 05
Names of Switch
Band Selector Switch
Record/Playback Switch
Power Switch
Function Selector Switch
FM Mode Selector Switch
Tape Selector Switch
Switch Position
FM-SW1 -SW2 -AM
-
Playback - Record
&l - Off
Tape/Line in - Radio
Mono - Stereo
_~
&I+ - NormalKrOz
I
SW201 (A - D) Dubbing Switch
SW202 (A - D) Input Selector Switch
SW203 Beat Cancel Switch
On-Off
Line - Phono
A-B-C
SW204
I Record Muting Switch I On
- Off
I
SW205
SW301
SW501
1 Deck 1 Main Switch
/ Deck 2 Main Switch
I Deck 1 Plav Switch
1 Deck 2 Plav Switch
I On - Off
~ -1
SW502 I On - Off
I
SW503
I On - Off
I
I On - Off I
Metal - NormaVCrOz
Metal - Normal/CrOz
On _ Off
SW508
I Deck 2 Cue/Review Switch
I On - Off I
SW509
1 Deck 2 Pause Switch / On - Off
1
SW601 1 AC/DC Selector Switch I
AC - DC
I
l The voltage in each part is measured with
nosignalgiven.
l As for the radio circuit, the voltage indica-
tion without parentheses is in FM stereo
mode,
and that with parentheses is in
MWILWISW mode.
. As for the audio circuit, the voltage indica-
tion is in play mode at normal speed. The
voltage indication with parentheses, for
0105 -
Q510, is in play mode at high
speed.
Parts marked with “8” ( ) ace important
for maintaining the safety of the set. Be sure
to replace these parts with specified ones for
maintaining the safety and performance of
theset.
l Specifications or wiring diagrams of this
model are subject to change for improve-
ment without prior notice.
VHIIR3108A/-1 (IR3108A)
Block Diagram of APSS Integrated Circuit
Amplifier
Constant
circuit
- voltageDetection Rectifier Comparisor Schmidt
circuit
circuit
circuit circuit circuit
FRONT VIEW
I 2 3 4 I 6
7 6 9
Figure 18 BLOCK DIAGRAM OF INTEGRATED CIRCUIT
-18-

1
I
2
3 4
I
5
I 6
D
BOTTOM VIEW
E
F
G
H
-
TOP VIEW
I
2 3 I
4
5
I
6
Figure 19 DECK 1 MECHANISM EXPLODEDVIEW
1
-19-

1 J
2 3 4 I
5
I
6
1
i
BOTTOM VIEW
TOP VIEW
A
0
C
D
E
F
G
~
H
1 I 23 I 4
I
5
I
6
I
Figure20 DECK 2 MECHANISM EXPLODED VIEW
-2o-