Tuner Section - Sharp CD-BA250H Service Manual

CD-BA250H/CD-BA2600H

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
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.16-2 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
1,620 kHz T351 *1
522 kHz (fL): T306 *2
1.1 ± 0.1 V
990 kHz (fL): T303 *1
ANTENNA
Figure 16-1 ADJUSTMENT POINTS
• FM
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.
MAIN PWB
SO302 CNP302
FM AM LOOP
ANTENNA
FE301
R336
TP301
T351
AM IF
TP302
CD ERROR CODE DESCRIPTION
Error
0001
0002
0101
0103
0201
0203
0302
0306
0307
0308
– 16 –
T303
AM
TRACKING fL
AM BAND
COVERAGE fL
T306
R357
State Code
[Servo System Error]
Cannot detect Pickup-in SW
DSP access error
[Error during close operation]
Open/Close SW not functioning (Low → High)
Open/Close SW not functioning (High → Low)
[Error during open operation]
Open/Close SW not functioning (Low → High)
Open/Close SW not functioning (High → Low)
[Error during skip operation]
Pickup-in SW is not detected
During Disc 1 search, Open/Close SW or Clamp SW
or Disc SW do not change to low.
Clamp SW not function (Low → High)
Clamp SW not function (High → Low)
T
Stopped
CH1=500 mV CH2=200 mV CH3=1 V
DC 10:1 DC 10:1 DC 10:1
T
FDO
1
TE
3
EFBL
2
=Filter= =Offset= =Record Length=
Smoothing : ON CH1 : 0.000 V Main : 100 K
BW : FULL CH2 : 0.000 V Zoom : 2 k
CH3 : 0.00 V
CH4 : 0.00 V
Figure 16-2
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
0.2 µs
Hold off :