JVC KW-XC828 Service Manual page 34

KW-XC828
Mechanism Adjustment Section
Item
"Head Height Adjustment"
1.Head azimuth
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 adjustment
2. After switching from REV to FWD then to REV, check that the
3. Adjust the azimuth screw B so that line "B" of the mirror tape
"Head Azimuth Adjustment"
1. Load the test tape (VT724: 1kHz) and play it back in the
2. Load the test tape (VT703: 10kHz) and play it back in the
3. Engage the reverse mode and adjust the output level to
4. When switching between forward and reverse modes, the
5. When the test tape (VT721 (315Hz )) is played back, the level
1. Check to see if the reading of the frequency counter & Wow
2. Tape Speed
and
Wow & Flutter
2. In case of out of specification, adjust the motor with a built-in
1. Play the test tape (VT724 : 1kHz) back.
3. DOLBY NR
2. Adjust the VR191 (Lch) and VR291 (Rch) so that the DOLBY NR
level adjustment
1-34
Adjusting & Confirmation Methods
screw 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.
head position set in procedure "1" is not changed.
*If the position has shifted, adjust again and check.
runs in the center between Lch and Rch in the forward play
mode.
reverse play mode. set the Rch output level to maximum.
forward play mode. Adjust the Rch and Lch output levels to
maximum, with azimuth adjustment screw B .
In this case, the phase difference should be within 45 .
maximum, with azimuth adjustment screw C .
difference between channels should be within 3dB.
*Between FWD Lch and Rch, REV Lch and Rch.
difference between channels should be within 1.5dB.
flutter meter is within 3015-3045 Hz (FWD/REV), and less than
0.35% (JIS RMS).
volume resistor.
level is 27.5mV 0.5dB by TP191 (Lch), TP291 (Rch).
Adjust Std. Value
Head shield
The head is at low position
during FWD.
Head shield
The head is at height position
during REV.
Playback head
FWD adj.
B
REV adj.
C
Height adj.
A
Phase
0
45
Tape Speed
Built-in
3015-3045Hz
volume resistor
Wow & Flutter
Less than
0.35%
(JIS RMS)
Speaker out
VR191:Lch
1kHz/10kHz
VR291: Rch
: -1dB 3dB,
63Hz/1kHz
: 0dB 3dB,