Panasonic RQ-J6 - Measurements and Adjustments; Head Azimuth Adjustment; L-CH;R-CH Phase Adjustment; Tape Speed Accuracy Adjustment

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.
L-ch
peak
level
p
oh
peak
level
tg
Fig. 5
Playback LINE ]
Fig. 4
Tape speed accuracy Tape speed accuracy
adjustment
Condition:
* Playback mode
ae ea tet 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
Ee
cuisecat:
ee
el
section
of
test
tape.
Playback
mode
tal
RiP
salen
.
t
|
|
|
electronic
counter
leet
eta
“°"
|
5.
On
the
basis
of
3,000Hz,
a
by
following
formula:
Fig.
6
*
Test
tape
---
QZZCWAT
Tape
speed
accuracy
=
aot
x
100
(%)
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