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MEASUREMENTS AND ADJUSTMENTS
NOTES:
@ Make sure heads are clean.
@ Volume control (L-CH, R-CH): Maximum
@ Make sure capstan and pressure roller are clean.
@ Mode select switch: STEREO
e Judgeable room temperature: 20+5°C (68+9°F)
e Mixing switch: OFF
ITEM
MEASUREMENT
& ADJUSTMENT
L-CH/R-CH output balance adjustment
1. Make connections as shown in fig. 1.
2. Playback the 8kHz signal from the test tape
(QZZCFM).
Adjust screw (B) in fig. 2 for
maximum output L-CH and R-CH levels.
Head azimuth adjustment
Condition:
* Playback mode
Record/playback
head
Equipment:
«*VTVM
« Oscilloscope
"VTVM
Oscilloscope
Tes ae Gotti)
When the output levels of L-CH and R-CH are
aspaenemags
)
- QZZCFM
not at maximum at the same time, readjust as
Fig. 1
follows.
Record/playback
3. Turn the screw shown in.fig. 2 to find angles A and C (points where peak
C
head
out put levels for left and right channels are obtained).
Then, locate the
angle B between angles A and C, i.e, a point where L-CH and R-CH
7
out put levels come together at maximum. (Refer to figs. 2 and 3.)
2
Screw
(B
L-CH/R-CH phase adjustment
Fig. 2
4 Make connections as shown in fig. 4.
5. Playback the 8kHz signal from the test tape (QZZCFM).
Adjust screw
(B) shown in fig. 2 so that pointers of the two VT VMs swing to maximum
and a waveform as Illustrated in fig. 5 is obtained on the oscilloscope.
Fig. 5
Playback
LINE
]
Fig. 4
Tape speed accuracy
Tape speed accuracy
adjustment
Condition:
* Playback mode
ae
e a
t e t
Record/playback
1. Test equipment connection Is shown in fig. 6.
aad
LINE OUT
2. Playback test tape (QZZCWAT 3,000HZz), and supply playback
eee)
signal to frequency counter.
oe
seam
where, f= measured value
Standard value: 2.5%
_ If measured value is not within standard, adjust tape speed adjustment VR (shown in electrical parts
location), so that frequency becomes 3,000 Hz.
CAUTION:
Playback frequency
response table
Playback frequency
response
|
Condition:
* Playback mode
Be sure to unplug the headphones while measurements and adjustments.
(Measured values may vary with the headphones plugged in or unplugged.)
125 Hz
—1+4dB
1. Test equipment connections is shown in fig. 1.
ee
0 dB
2. Playback frequency response test tape (QZZCFM).
ai
3. Measure output level at 315Hz, 125Hz, 1kHz, 4kHz, 8kHz and compare
|
L kHz
Epis
each output level with standard frequency 315Hz, at LINE OUT.
| 4kHz
| —0.9+4dB
4 Make measurement for both channels.
Q kHz
pees 15+5cdB
5. Make sure that the measured value is within the range specified in the
frequency response table (shown in fig. 7).
Fig. 7
Equipment:
*VTVM
« Oscilloscope
* Test tape --- QZZCFM
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