JVC KD-21 - Page 9

KD-21A/B/E/U
KD-15A/B/C/E/J/U
Ee A
4 Meter gain 1. Set the deck to the record mode and in- (Main amp 1. When LINE OUT level are
adj. put the 1kHz (-10dB) signal to LINE c.biard 0.42V (-5.5dBs), VU meter
IN jacks. TAA338101-01) indicate OVU.
2. Adjust the recording level control so 2. Adjust right and left channel.
that the LINE OUT becomes -5.5dBs
3. Adjust VR103 and VR203 so that the VR103,203
VU meters indicate zero VU.
1. Adjust playback sensitivity
when heads are replaced.
2. Do this adjustment after
making sure level meter
deflection angle is correct.
5 Playback
sensitivity
Main amp
c.board
VR101,201
. Set equalizer switch at normal.
2. Playback reference tape VTT-664, and
adjust semi-fixed resistors VR101 (L ch)
and VR201 (R ch) so that the VU meters
indicate zero VU. (-5.5dBs at LINE OUT)
If L and R channel output
level difference is 3~4dB, re-
place the head.
6 REC/PB
head
(Azimuth
inclination)
1. Playback the azimuth adjustment re-
ference tape VTT-658, 10kHz, turn the
azimuth screw so that the output will
become maximum.
2. After this adjustment, the screw should
be locked with a bond.
Playback reference tape VTT-656, 3kHz,
and adjust the semi-fixed resistor in motor
case so that the speed is 3000Hz +2%.
8 Wow flutter Playback reference tape VTT-656, 3kHz, less than} at RMS
and check the wow flutter less than 0.3%. 0.3%
3000Hz
+2%
Adjustment
hole on
motor case
7 Motor speed
9 P.B. 1. Playback reference tape VTT-675N(1kHz).
frequency check the frequency responce to be as
responce follows.
measuring reference frequency 1kHz
‘: 63Hz = -1dB+5dB
enrome —40kHz -3dB+3dB
63Hz = -1dB+5dB
10kHz O0dB+3dB
normal
10 Record/ reference frequency1kHz
. Set the deck to the record mode.
Playback 2. Oftain the zero VU meter level at record- 5OHz -2+4dB
frequency ing (1kHz) attenuate signal by 20dB chrome 10kHz O0+5dB
responce record and playback at 1kHz, 50Hz and 50Hz -244dB
measuring 10kHz. need 10kHz 0+5dB
Adjust VR1 or VR106,206 semi-fixed
resistors so that out put level difference
become as remarks.
11 Bias . Set the deck to the pause mode. Main amp . Adjust bias current when
current 2. With no signal, connect a 100Q resistor c.board heads or other parts are
in the ground side of the head and chrome chrome placed.
connect the V.T.V.M. across the resistor VR106,206 45mV 2. Use the highclass V.T.V.M.
and set the BIAS SW at chrome or normal normal for high frequency responce.
VR1 75mV
normal.
First adjust for chrome tape, then for 3. After the bias current ad-
normal tape. justment, check the fre-
quency responce at 10kHz
signal input.
4. The earth wire of the head
is the one which VU meter
moves, when you touch the
head tip by your finger at
the playback mode.
3. When adjust the bias current, should be
used the shield wire.
ae No, 4150