JVC KD-X2 - Page 8

KD-X2 A/B/C/E/G/E/J/
fag Standard
fag value
Connect the frequency counter to the | L951 95 kHz
+1 kHz
Recording |
frequency
response
pin 2 of L951 through a 1.2 MQ
resistor, then adjust L951 so that
the counter reads 95 kHz.
Checking
record/
play back
distortion
7 7 Checking
signal to
noise ratio
in recording/
playback
Checking
erasing
coefficient
8 (No. 4250)
1)
NR
switch:
OFF
For
With
respect
|
This
checking
should
be
performed
2)
Record
a
1
kHz
signal
at
an
input
|
Normal
to
1
kHz
for
normal
tapes
and
for
both
right
reference
level of
—20dB,
then
|
tape:
reference:
and
left
channels.
record
50
Hz
and
12.5
kHz
signals
|
vR
152
At
50
Hz,
1.
Bias
current
adjustment
for
a
cas-
and
play
them
back.
At
this
time,
|
(LCH)
O0+3
dB;
sette
deck
should
generally
be
per-
adjust
VR
152
and
VR252so
that
|vyR252
|At12.5kHz,|
formed
referring
to
the
record/
the
deviation
of
50Hz
and
12.5
|
(RCH)
0+3dB
playback
frequency
response.
kHz outputs satisfy the standard
values with respect to 1 KHz output.
This is because the frequency re-
sponse of a cassette deck depends
more greatly on the bias current
than does that of an open reel
deck.
2. If the bias current is not proper-
ly adjusted, the record and play-
back characteristics become as
shown left.
Response (dB) Increase in high frequencies | 4. bias current
. oa Appropriate bias current
Decrease in high frequencies High bias current
O 50 Hz 1 kHz 12.5 kHz Frequencies
The level difference between left
and
right
channels
for
SF/NORM
tape and chrome tape should be less
than
3
dB.
Perform
the
adjustment
using a normal tape, level difference
between recording and playback for
SA/CrO2
and
metal
tapes,
should
be
less
than
3
dB,
and
that
between
left and right channels should also
be less than 3 dB.
. Apply a 1 kHz —23 +3 dBV Sig-
nal to the LINE. in terminals,
play back the recorded part,
and check so that Line out ter-
minal level become O + 2.0 dB.
0+2.0dB
. If the standard value cannot be
obtained, adjust the recording
level using R165 and R166 in
combination (for L-ch), andR265
and R266 (R-ch), respectively.
. Record a 1kHz, —8dB signal to
LINE IN terminals and perform
recording with the multi-peak
becomes to 0.
2. Play back the recorded part. Check
the output with a distortion meter
to see if the value conforms to the
standard value.
. Record a 1 kHz, 0 dB signal.
Stop the input by disconnecting
from the terminal to perform non-
signal recording.
2. Play back the recorded part.
Measure the 0 dB recording output
and the non-signal recording output
for Comparison using an electronic
voltmeter.
Check to see if the value conforms
to the standard value.
. Apply a 1 kHz signal to the LINE -More than For the measuring, connect a band
IN terminals. Adjust the recording 65 dB pass filter between the deck and the
level controls until the multi-peak electronic voltmeter.
indicator becomes 0 dB. . Input Tape deck
2. Perform recording with the signal (1 kHz OdB (recording,
enhanced by 20 dB. + 20 dB) erasing)
3. Erase a part of the recording.
4. Measure the output difference be- ;
Band pass Electronic
tween the erased part and non- filter voltmeter
erased part to compare with an ———~
electronic voltmeter. (1kHz)
NORM
tape; Less
than 2.0%
CrO2 tape;
Less than 3%
Metal tape;
Less than 2%
(THD)
NORM,
CrO2 and
Metal tapes;
More than
42 dB
Be sure to perform this checking
following bias current and record-
ing level checking.
Apply an output (—72 dBs) to the
MIC terminals with the recording
level controls set to maximum so
that the multi-peak indicator be-
comes O dB.