Tuner Section - Sharp CD-M4000W Service Manual

CD-M4000W/CP-M4000

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
SO301
FM ANTENNA
TERMINAL
IC301
TP301
C393
T301
FM BAND
COVERAGE fL
T351
AM IF
Figure 14-1 ADJUSTMENT POINTS
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.14-2 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
Frequency Setting/
Instrument
Display Adjusting
Connection
Parts
1,602 kHz T351 *1
531 kHz (fL): T306 *2
1.1 ± 0.1 V
990 kHz (fL): T303 *1
Output: TP302
Output: TP301
CNP301
AM LOOP
MAIN PWB
ANTENNA
T303
AM
TRACKING fL
L312
T302
T306
FM IF
FM RF
AM BAND
COVERAGE fL
TP302
R357
• FM RF
Signal generator: 1 kHz, 40 kHz dev., FM modulated
Test Stage Frequency Frequency
FM Band —
Coverage
FM RF 98.00 MHz 98.00 MHz
(10-30 dB)
*1. Input: Antenna
*2. Input: Antenna
• FM IF
Signal generator: 10.7 MHz, FM modulated
Test Stage Frequency Frequency
IF 10.7 MHz
*1. Input: Antenna
T
Stopped
CH1=500 mV CH2=200 mV
DC 10:1
T
FDO
1
TE
3
EFBL
2
=Filter= =Offset=
Smoothing : ON CH1 :
BW : FULL CH2 :
CH3 :
CH4 :
– 14 –
Setting/
Display Adjusting
Point
87.50 MHz T301(fL):
1.3 V ± 50 mV
L312
Output: TP301
Output: Speaker terminal
Setting/
Display Adjusting
Point
98 MHz T302
(Turn the
core of trans-
former T302
fully counter-
clock wise)
Output: TP301
1999/04/05 20:26:47
CH3=1 V
DC 10:1 DC 10:1
=Record Length= =Trigger=
0.000 V Main : 100 K Mode : SINGLE
0.000 V Zoom : 2 k Type : EDGE CH1
0.00 V Delay :
0.00 V Hold off :
Figure 14-2
Instrument
Connection
*1
*2
Instrument
Connection
*1
500 ms/div
(500 ms/div)
NORM:20 kS/s
CH2
v/DIV
200 mV
0.0 ns
0.2 µs