Sharp SD-EX100H (serv.man21) Service Manual ▷ View online
– 13 –
SD-EX100H
Inspection method of a 12-cm disc sensor
The sensor is located on the right of the insertion slot when you face the unit.
When the unit is in ejecting completed state, insert a card between the photo interrupters to cover the sensor. Check the change
in voltage while observing output (QD02 collector).
Note) When a 12-cm disc is loaded, the sensor cannot be blocked.
When the unit is in ejecting completed state, insert a card between the photo interrupters to cover the sensor. Check the change
in voltage while observing output (QD02 collector).
Note) When a 12-cm disc is loaded, the sensor cannot be blocked.
Card
(A1)x1
(B1)x1
How to remove a CD (opening the CD door)
(See Fig. 13-2)
(See Fig. 13-2)
1. Rotate a worm gear (A1) x 1 downward when the CD slot is
closed.
2. The disc is unchucked to open the CD slot.
3. Place the unit upside down and remove the CD.
3. Place the unit upside down and remove the CD.
Figure 13-1
Figure 13-2
Figure 13-3
How to move the tray manually
(See Fig. 13-3)
(See Fig. 13-3)
Note) You can manually move the tray by removing the CD
mechanism from the unit.
1. Lower the CD mechanism.
2. When the tray is locked, move a lock lever (B1) x 1 downward
mechanism from the unit.
1. Lower the CD mechanism.
2. When the tray is locked, move a lock lever (B1) x 1 downward
using a thin screwdriver.
3. The unlocked tray can be moved by hand. (However, the
tray is locked again if it is lowered to bottom.)
SD-EX100H
– 14 –
TUNER SECTION
Item
Point to be adjusted
Setting value
IF
Set the display of T51
Maximize the IF
to 1,620kHz.
waveform (450kHz).
Frequency
fL: T21 (530kHz)
fL : 1.3V
±
0.1
coverage (voltage Set the display to 530kHz. fH : 8.5V
±
1.3V
of TP301VT line) fH: (1,620kHz)
(Just check fH.)
Tracking
fL : T20 (990kHz)
Maximize the output of
the headphone terminal.
the headphone terminal.
fL: Low-range frequency
fC: Middle-range frequency
fH: High-range frequency
fC: Middle-range frequency
fH: High-range frequency
• Adjusting and checking AM IF/RF
ADJUSTMENT
Figure 14-1AM IF/FREQUENCY COVER
Electric
Voltmeter
GND
AM Loop Antenna
AM signal oscillator
Loop Antenna
UNIT
IF : Headphones
Frequency Cover : TP301
Frequency Cover : TP301
Frequency
Display
Adjusting
Parts
Instrument
Connection
90 MHz
90 MHz
VR31
Input: SO101
(28 dB)
Output: Headphones
(EMF.)
Terminal
• FM Mute Level
Signal generator: 400 Hz, 22.5 kHz, FM modulated
Signal generator: 400 Hz, 22.5 kHz, FM modulated
Electric
Voltmeter
GND
FM Signal Oscillator
UNIT
Headphones
Terminal
SO101
Figure 14-2 FM MUTE LEVEL
Figure 14-3 ADJUSTMENT POINT
AM IF
FM MUTE
LEVEL
AM
TRACKING fL
SO101
ANTENNA
TERMINAL
ANTENNA
TERMINAL
AM BAND
COVERAGE
VR31
T51
T20
T21
FE10
FM
GND
GND
AM
TUNER PWB
TP301
– 15 –
SD-EX100H
TEST MODE
When the tuner test mode is set, the initial setting of frequencies
is stored in the preset memory as shown in Table 1. For
details, refer to "4. Tuner test" on page 19.
The frequencies registered by the user will be changed when
the below setting is performed.
is stored in the preset memory as shown in Table 1. For
details, refer to "4. Tuner test" on page 19.
The frequencies registered by the user will be changed when
the below setting is performed.
Preset
Memory
Frequency
FM
Preset
Memory
Frequency
AM
M1
87.5 MHz
M6
522 kHz
M2
108.0 MHz
M7
1,620 kHz
M3
90.0 MHz
M8
603 kHz
M4
106.0 MHz
M9
1,404 kHz
M5
98.0 MHz
M10
990 kHz
Table 1 Memory setting
Figure 15-1 OUTPUT OFFSET LEVEL
CD SECTION
A built-in auto adjustment of this CD system does not require readjustment after pickup replacement.
You can freely mix and match PWB and pickup.
Auto adjustment is performed for each disc to realize optimum playback.
You can freely mix and match PWB and pickup.
Auto adjustment is performed for each disc to realize optimum playback.
To clear registered stations
Canceling the test mode will clear all the preset data.
Canceling the test mode will clear all the preset data.
Adjustment for 1 bit amplifier output offset
voltage
voltage
Adjust VRA100 and VRA101 so that the voltage between the
positive and negative terminals of the speaker output terminal
(JK400) is within 0
positive and negative terminals of the speaker output terminal
(JK400) is within 0
±
5mV at AC 230V.
Electric
Voltmeter
JK400
AC 230V
UNIT
Output
Speaker
Terminal
Speaker
Terminal
+
–
VR : 0
Input:AUX
Input:AUX
Figure 15-2 ADJUSTMENT POINT
L-CH OUTPUT
OFFSET
OFFSET
R-CH OUTPUT
OFFSET
OFFSET
VRA100
VRA101
1-BIT AMP. PWB
SD-EX100H
– 16 –
DESCRIPTION OF CIRCUIT FOR 1-BIT UNIT
(SEE THE WIRING DIAGRAMS ON PAGES 42 AND 43.)
Input
Signals over certain level input from BIA106 are sliced into
waveforms by RA173 (RA174), DA126, and DA127 (DA128,
DA129).
The slice levels depend on the output of the unit.
In case of 25 W output setting, the level is set to gain distortion
of approx. 10 % during output.
The level on the positive side is determined by RA175, RA177
and RA179 and that on the negative side by RA176, RA178,
and RA180, respectively.
After DC cut by CA109, the signals are input to AD conversion
IC.
Signals over certain level input from BIA106 are sliced into
waveforms by RA173 (RA174), DA126, and DA127 (DA128,
DA129).
The slice levels depend on the output of the unit.
In case of 25 W output setting, the level is set to gain distortion
of approx. 10 % during output.
The level on the positive side is determined by RA175, RA177
and RA179 and that on the negative side by RA176, RA178,
and RA180, respectively.
After DC cut by CA109, the signals are input to AD conversion
IC.
modulation 1-bit conversion
The signals input to the AD conversion IC are converted into
1-bit signals for differential output.
For detailed technical description of 1-bit signal conversion,
refer the technical manual for SM-SX100 already published.
The signals input to the AD conversion IC are converted into
1-bit signals for differential output.
For detailed technical description of 1-bit signal conversion,
refer the technical manual for SM-SX100 already published.
Dead time and level shift
When the 1-bit signals are output from the AD conversion IC,
the leading edge of the waveform is delayed for 20 to 25 nsec
by DA103 (DA102, DA101, and DA100), RA115 (RA114,
RA113, and RA112), and CA155 (CA154, CA153, and CA152),
compared with the trailing edge.
As mentioned below, this operation is for reducing switching
circuit loss in the final stage.
The signals are input to the buffer IC (AND gate IC) for the
waveform format and are output.
When the 1-bit signals are output from the AD conversion IC,
the leading edge of the waveform is delayed for 20 to 25 nsec
by DA103 (DA102, DA101, and DA100), RA115 (RA114,
RA113, and RA112), and CA155 (CA154, CA153, and CA152),
compared with the trailing edge.
As mentioned below, this operation is for reducing switching
circuit loss in the final stage.
The signals are input to the buffer IC (AND gate IC) for the
waveform format and are output.
Low-pass filter circuit
The 1-bit signal switched by output IC converts to analog by
going through a low pass filter comprised of LA100 (LA102,
LA104, LA106) and CA142 (CA143, CA150, CA151).
The characteristic of the low pass filter does not fluctuate up
to 20 kHz and approx. 3 dB attenuates at around 40 kHz.
The 1-bit signal switched by output IC converts to analog by
going through a low pass filter comprised of LA100 (LA102,
LA104, LA106) and CA142 (CA143, CA150, CA151).
The characteristic of the low pass filter does not fluctuate up
to 20 kHz and approx. 3 dB attenuates at around 40 kHz.
Dynamic feedback circuit
The 1-bit signal switched by output IC oscillates between +
and – power sources.
The resistance is divided to feed back the signal through NF
resistance 75 k
The 1-bit signal switched by output IC oscillates between +
and – power sources.
The resistance is divided to feed back the signal through NF
resistance 75 k
Ω
to AD conversion IC. The P-P voltage
measures approx. 5 V at this time.
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