Tuner Section - Sharp CD-XP300H 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 Output: TP302
*2. Input: Antenna Output: TP301
T351
AM IF
TP302
L354
R357
AM BAND
COVERAGE fL
Figure 15-1 ADJUSTMENT POINTS
• FM IF
Notes:
1: Description of the "FM IF Adjustment" is not carried on this
Manual. It is because the IF coil in the FM front end section
has been best adjusted in the factory so that its further
adjustment is not needed at the field. When replacing the
FM front end assembly, no adjustment is needed either.
2: The parts in the FM front end section are prepared in a
complete unit, so you can't obtain each part individually.
Frequency Setting/
Instrument
Display Adjusting
Connection
Parts
1,620 kHz T351 *1
522 kHz (fL): T306 *2
1.1 0.1 V
990 kHz (fL): T303 *1
MAIN PWB
R381
FE301
TP301
T303
T306
AM TRACKING
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
01
SO301
FM ANTENNA
TERMINAL
10*
CNP301
AM LOOP
ANTENNA
11*
31
* '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.
Stopped
CH1=500 mV
DC 10:1
T
FDO
1
TE
3
EFBL
2
=Filter=
Smoothing : ON
BW : FULL
– 15 –
Explanation
When Pickup set inner position, inner switch
cannot detect 'ON' level for 10 secs.
When tray moves to Open/Close, Open/Close switch
cannot detect 'ON' level for 7 secs.
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,
"CLAMP SW", "DISC NO SW" and "OPEN/CLOSE"
cannot detect 'ON' level for 14 secs.
When it changes to CD function, DSP cannot read
initial data.
T
CH2=200 mV CH3=1 V
DC 10:1 DC 10:1
=Offset= =Record Length=
CH1 : 0.000 V Main : 100 K
CH2 : 0.000 V Zoom : 2 k
CH3 : 0.00 V
CH4 : 0.00 V
Figure 15-2
CD-XP300H
1999/04/05 20:26:47
500 ms/div
(500 ms/div)
NORM:20 kS/s
CH2
v/DIV
200 mV
=Trigger=
Mode : SINGLE
Type : EDGE CH1
Delay : 0.0 ns
Hold off : 0.2 s