JVC KS-FX321, Service Manual

Page: 14 / 49

KS-FX321
1-14 (No.49771)
Mechanism adjustment section
Item Adjusting & Confirmation Methods Adjust Std. Value
Head shield
Head shield
The head is at low position
during FWD.
The head is at height position
during REV.
A Line
B Line
Phase
screw (c)
screw (a)
screw (b)
Head azimuth
screw
Fixed screw
0
°
45
°
1. Head azimuth
2. Tape Speed and
Wow & Flutter
3. Playback
Frequency
response
"Head Height Adjustment"
Note
Adjust the azimuth directly. When you adjust the height
using a mirror tape, remove the cassette housing from the
mechanism chassis.
After installing the cassette housing, perform the azimuth
adjustment.
1. Load the mirror tape ( SCC-1659 ). Adjust with height
adjustmentscrew (a) and azimuth adjustment screw (b) so
that line "A" of the mirror tape runs in the center between
Lch and Rch in the reverse play mode.
2. After switching from REV to FWD then to REV, check that
the head position set in procedure "1" is not changed.
*If the position has shifted, adjust again and check.
3. Adjust the azimuth screw (b) so that line "B" of the mirror
tape runs in the center between Lch and Rch in the forward
play
mode.
"Head Azimuth Adjustment"
1. Load the test tape ( VT724: 1kHz ) and play it back in the
reverse play mode. set the Rch output level to maximum.
2. Load the test tape ( VT703: 10kHz ) and play it back in the
forward play mode. Adjust the Rch and Lch output levels
tomaximum, with azimuth adjustment screw (b).
In this case, the phase difference should be within 45°.
3. Engage the reverse mode and adjust the output level to
maximum, with azimuth adjustment screw (c).
*The phase difference should be 45° or more.
4. When switching between forward and reverse modes, the
difference between channels should be within 3dB.
*Between FWD Lch and Rch, REV Lch and Rch.
5. When the test tape ( VT721 : 315Hz ) is played back, the
level difference between channels should be within 1.5dB.
1. Check to see if the reading of the frequency counter & Wow
flutter meter is within 2940-3090 Hz ( FWD/REV ), and less
than 0.35% ( JIS RMS ).
2. In case of out of specification, adjust the motor with a built-
in volume resistor
Built-in
volume resistor Tape Speed
2940-3090Hz
Wow&Flutter
Less than
0.35%
(JIS RMS)
Speaker out
1kHz/8kHz
: 0dB_}3dB,
125Hz/1kHz
: -4dB+2dB,
1. Play the test tape ( VT724 : 1kHz ) back and set the volume
position at 2V.
2. Play the test tape ( VT739 ) back and confirm 0
±
3dB at 1kHz/
8kHz and -4+2dB at 1kHz/125Hz.
3. When 8kHz is out of specification, it will be necessary to
read adjust the azimuth.
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