JVC CA-UXG1, Руководство по обслуживанию

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(No.MB412)1-15
4.6 Cassette amplifier section
4.7 Tuner section
Item Measuring condition Check and adjustment procedure Standard value Adjusting part
Head azimuth
adjustment
Tape speed
and
wow/flutter
check and
adjustment
PB frequency
responce
check
Bias frequency
check
REC and PB
frequency
responce
adjustment
Head azimuth
adjusting screw
(to be used only
after head re-
placement)
Tape speed :
motor semifixed
resistor
check only
L203
Output level :
/-2dB
of maximum
output level
2940 to 3090 Hz
within 0.38%
(unweighted)
deviation between
1 kHz and 8 kHz :
0 (+3 to -6) dB.
Level difference
between REC and
PB : within 0
(+3 to 6) dB
Phase defference
L and R channels:
minimum
1.Plyback the test tape VT703.
2.Adjust the head azimuth adjusting screw
so that the phase difference between the
R and L channels is minimized at an
output level that is /- 2dB of the
maximum output level.
After this adjustment, lock the head
azimuth adjusting screw with screw
sealant to cover more than a half of the
screw head.
3.When the head azimuth is maladjusted,
correct it with the head azimuth adjusting
screw.
1.Plyback the test tape VT712 by the end
of position.
2.Connect a frequency counter and check
that it reads between 2940 and 3090 Hz.
If not, adjust the frequenct with the motor
semifixed resistor.
3.Check that the wow / flutter is 0.38%
(unweighted).
Playback the test tape VT738 while confir-
ming that deviation between the 1 kHz
signal and 8 kHz signal should be
0 (+3 to -6) dB.
Set the TUNER or CD function and with
TAPE to record. Check to see if the
frequency at the measuring point (R335 or
R336) is 60 kHz +/-1 kHz if not adjust T360
until the frequency counter indicates
60 kHz +/- 1 kHz.
At TUNER, set the BAND to the FM
position, and record the reference 1 kHz
signal and 8 kHz signal altemately
repeatedly. While playing back the
recorded signal differ from that of the 1 kHz
signal by within 0 (+3 to 6) dB.
Test tape : VT703
Signal output terminal :
PHONES
(with 32 ohm load)
Test tape : VT712
Signal output terminal :
PHONES
(with 32 ohm load)
Test tape : VT738
Signal output terminal :
PHONES
(with 32 ohm load)
Test tape : normal
Signal output terminal :
Casssette R/P head
Test tape : AC225
Signal input : FM 22.5
dev, 60dBu with
emphasis
Signal output terminal :
PHONES
(with 32 ohm load)
Item Measuring condition Check and adjustment procedure Standard value Adjusting part
AM IF
adjustment
AM tracking
adjustment
Tuner 114 kHz
filter the waves
adjustment
T203
T201
T204
R245
TC201
1.Set the intermediate frequency sweep
generator to AM 450 kHz.
2.Adjust the T203 from maximum and
center output.
1.Set the TUNER at 522 kHz adjust T201
until the test pin of R245 voltage at
1.55 V +/- 0.1 V.
2.Set the TUNER at 1629 kHz, check the
pin of R245 voltage at 8.4 V +/- 6V.
3.Set the TUNER ang S/G at 612 kHz,
adjust T202 for maximum output.
4.Set the TUNER and S/G at 1404 kHz,
adjust T201 for maximum output.
5.Repwat the above step 3 and 4.
1.Set the unit in standby mode. Input 114
kHz signal to IC101 pin 19.
2.Adjust the T204 for output voltage
minimum.
Signal input : Loop
antenna
Signal output : IC201
pin 18
Signal input : Loop
antenna
Signal output : PHONES
(with 32 ohm load)
Signal input : IC101
pin 19
Signal output : IC101
pin 18