Tuner Section - Sharp CD-XP300 - Compact Stereo System Service Manual

TUNER SECTION

fL: Low-range frequency
fH: High-range frequency
AM IF/RF
Signal generator: 400 Hz, 30%, AM modulated
Test Stage Frequency
AM IF 450 kHz
AM Band —
Coverage
AM Tracking 990 kHz
*1. Input: Antenna
*2. Input: Antenna
FM RF
Signal generator: 1 kHz, 40 kHz dev., FM modulated
Test Stage Frequency Frequency
Display
FM Band — 87.50 MHz
Coverage
FM RF 98.00 MHz 98.00 MHz
(10-30 dB)
*1. Input: Antenna Output: TP301
*2. Input: Antenna Output: Speaker terminal
FM IF
Signal generator: 10.7 MHz, FM modulated
Test Stage Frequency Frequency
Display
IF 10.7 MHz 98 MHz
*1. Input: Antenna
MAIN PWB
FM BAND
COVERAGE fL
T302
1
L312
T303 R316
TP301
AM TRACKING
fL
Figure 15-1 ADJUSTMENT POINTS
Frequency Setting/
Instrument
Display Adjusting
Connection
Parts
1,702 kHz T351 *1
530 kHz (fL): T306 *2
1.1 0.1 V
990 kHz (fL): T303 *1
Output: TP302
Output: TP301
Setting/
Instrument
Adjusting
Connection
Point
T301 (fL): *1
1.3 V 0.1 V
L312 *2
Setting/
Instrument
Adjusting
Connection
Point
T302 *1
(Turn the
core of trans-
former T302
fully counter-
clock wise)
Output: TP301
T301 T351
AM IF
FM IF
FM RF
T306
R356
TP302
AM BAND
COVERAGE fL
CD SECTION
• Adjustment
Since this CD system incorporates the following automatic
adjustment functions, readjustment is not needed when
replacing the pickup. Therefore, different PWBs and pickups
can be combined freely.
Each time a disc is changed, these adjustments are
performed automatically. Therefore, playback of each disc
can be performed under optimum conditions.
Items adjusted automatically
(1) Offset adjustment (The offset voltage between the head
amplifier output and the VREF reference voltage is
compensated inside the IC.)
* Focus offset adjustment
* Tracking offset adjustment
(2) Tracking balance adjustment (waveform drawing
Fig.15-2 EFBL)
(3) Gain adjustment (The gain is compensated inside the IC
so that the loop gain at the gain crossover frequency will
be 0 dB.)
* Focus gain adjustment
* Tracking gain adjustment
CD ERROR CODE DESCRIPTION
Error
When Pickup set inner position, inner switch
01
cannot detect 'ON' level for 10 secs.
When tray moves to Open/Close, Open/Close switch
cannot detect 'ON' level for 7 secs.
10*
When disc table rotate to target position.
Clamp switch cannot detect 'ON' level for 7 secs.
When disc table set to Disc1 position for 1 st time,
11* "CLAMP SW", "DISC NO SW" and "OPEN/CLOSE"
cannot detect 'ON' level for 14 secs.
When it changes to CD function, DSP cannot read
31
initial data.
* 'CHECKING'
If Error is detected, 'CHECKING' will be display instead of 'ER-
CD**' display. 'ER-CD**' display will only be display when
error had been detected for the 5 th times.
T
Stopped
CH1=500 mV CH2=200 mV
DC 10:1 DC 10:1
T
FDO
1
TE
3
EFBL
2
=Filter= =Offset=
Smoothing : ON CH1 :
BW : FULL CH2 :
CH3 :
CH4 :
– 15 –
CD-XP300/CD-XP3300
Explanation
1999/04/05 20:26:47
CH3=1 V
DC 10:1
=Record Length=
0.000 V Main : 100K Mode : SINGLE
0.000 V Zoom : 2k Type : EDGE CH1
Delay :
0.00 V
Hold off :
0.00 V
Figure 15-2
500 ms/div
(500 ms/div)
NORM:20 kS/s
CH2
v/DIV
200 mV
=Trigger=
0.0 ns
0.2 s