Yamaha KX-E300, Service Manual

Page: 11 / 33

KX-E300
KX-E300
11
“ELECTRICAL ADJUSTMENT”
● Use 560 mV (250 nwb/m) for 0 dB as the standard level of the unit.
0dB = 250 nwb/m (315 Hz) = – 7 dBV (Rec out level)
Item to be
Adjusted
Playback
level (315Hz)
Confirmation of
playback frequency
response
Step
1
2
Rating
– 5 dBV
±
0.3 dBV
Check that the 10kHz playback
level is within 0
±
3 dB of the
1kHz playback level. (Fig. C)
Adjustment
parts
VR201 (L ch)
VR202 (R ch)
Tape
MTT-212N
315Hz,
250nwb/m
Test tape for frequency check.
3180
µ
s + 120
µ
s (LH) (MTT-256)
3180
µ
s + 70
µ
s (CrO
2
) (MTT-356)
Points of
measurement
LINE OUT
LINE OUT
Mode
PLAY
PLAY
Instrument
required
ACVM
ACVM
Oscilloscope
< Playback section >
Fig. C
±
4dB
±
3.5dB
1k
±
3dB
±
3dB
3k 10kHz 315 250 50 12.5kHz
●
PLAYBACK FREQUENCY RESPONSE
< Recording section >
Rating
Adjust for equal record and
playback levels.
(– 25 dBV
±
0.3 dBV)
Adjust for equal record and
playback levels.
(– 25 dBV
±
0.5 dBV)
Perform recording/playback
and confirm that the fre-
quency response shown in
Fig. D is obtained.
If not, perform adjustment
again at High (CrO
2
) so that
the frequency response in
Fig. D is obtained.
Perform recording/playback
and confirm that there is no
output level difference.
(– 25 dBV
±
0.5 dBV)
If the value is not as speci-
fied, perform adjustment
again according to Steps 1
and 2.
Item to be
Adjusted
Recording
level
Recording
bias
(Total
frequency
response)
Confirmation
of recorded
level
Step
1
2
3
Points of
measurement
LINE OUT
LINE OUT
LINE OUT
Mode
REC
PLAY
REC
PLAY
REC
PLAY
Instrument
required
ACVM
Audio
frequency
oscillator
ACVM
Audio
frequency
oscillator
ACVM
Audio
frequency
oscillator
Measurement
conditions
Input 315 Hz Signal
to LINE IN from Audio
Frequency Oscillator.
Adjust output level of
Audio Frequency Os-
cillator so that the
voltage of LINE OUT
becomes – 25 dBV.
Input 12.5 kHz Signal
to LINE IN from Audio
Frequency Oscillator.
Adjust output level of
Audio Frequency Os-
cillator so that the
voltage of LINE OUT
becomes – 25 dBV.
Tape
AC-514
High
(CrO
2
)
AC-514
High
(CrO
2
)
AC-225
Normal
(LH)
AC-514
High
(CrO
2
)
Adjustment
parts
VR203 (L ch)
VR204 (R ch)
VR103 (L ch)
VR104 (R ch)
●
TOTAL FREQUENCY RESPONSE ( – 20 dBV)
Dolby NR OFF / B on / C on
Type I (Normal) / Type II (High) / Type IV (METAL)
Fig. D
±
4dB
±
4dB
1k
±
3dB
±
3dB
3k 10kHz 315 250 50 12.5kHz