JVC RC-W410 - Main Adjustments; Adjustment Equipment and Cassette Calibration

RC-W410 secon |
Main Adjustments
(1) Equipment and Measuring Instrument used for Adjustments
e Electronic voltmeter e Wow-flutter meter e Torque testing cassette gauge CTG-N
e
Audio
frequency
oscillator
e
Frequency
counter
e
Alignment
tape
e Attenuator e Standard signal generator e Measuring tape : TS-8 (UR)
(2) Function of Cassette
® Condition for Measurement
Power
supply
......
AC
220—240
V/110—120
V
(50/60
Hz)
Function
position
..TAPE/FM
MODE:
TAPE
NORMAL
DC12V
FUNCTION
:
NORMAL
SPEED
Reference
output
...
Speaker
:
OdBs
(0.775
V)/8
2
SEA
:
Center
Headphone
:
—13 dBs
(0.173
V)/32
Q
3D
:
OFF
3D
2120
BEAT
CUT
>:
NORMAL
Reference
Input
.... Ext.MIC
:
—46dBs
e
Routine
of
Check
and
Adjustment
No.
Item
bi
aay
Check and
Adjustment
Adjusting
Point
1
|
Tape
speed
and
VTT712
Play
back
the
end
portion
of
the
VTT712
test
tape
and
check
Wow-fiutter
(3 kHz)
up
the following standards.
check -
adjustment
e
B Deck
:
at
Normal
speed
3000
Hz +
30 Hz
VR331
at
Normal speed
Less
than 0.38%
(JIS
UNWTD)
Check
e
A
Deck
:
at
Normal speed
+80 Hz
against
B
Deck
Check
at
Normal
speed
Less
than
0.38%
(JIS
UNWTD)
Check
C
2
|
High-speed
and
VTT712
1)
Loading
VTT712
on
A
Deck
and
Blank
tape
TS-8(UR)
on
B
Synchro
dubbing
|
(3 kHz)
deck.
check
TS-8
(UR)
2)
Function
position :
HIGH SPEED
3) B Deck : REC/PAUSE
4) B Deck pause to be released when playing A Deck, then start
High-speed dubbing.
5) High speed : Within 5600 Hz + 400 Hz to be check Check
3 VTT703L 1) Play back VTT703L, both A and B Deck.
Head azimuth Left side screw
adjustment (10 kHz) 2) Obtain maximum Playback output for this adjustment. of PB or R/P
3) Phase difference to be minimized. head
4) Screw lock to be applied after adjustment.
4
|
Playback
out-
VTT724
Play
back
the
VTT724
tape
on
B
Deck
and
confirm
that
level
Check
put level (1 kHz) difference between R and L channels is within 4 dB.
check (Measuring point : Headphone output)
5 | Playback VTT736 1) Play back VTT736 difference level against 1 kHz.
frequency (1kHz/125Hz, A Deck, BDeck..... Measuring point : Headphone output Check
characteristics 1kHz/8 kHz) 1kHz/125 Hz: O0dB+4dB
1kHz/8kHz : 1dB+4dB
2) Tape mode switched to Metal/CrO,
Play back VTT736 and check the difference between 1 kHz
and 8 kHz at Headphone output.
B Deck : within —1 dB +3 dB Check _|
6 | Bias frequency 1) B Deck : REC mode, Beat Cut : Position 1
2) Leakage of Bias at Headphone to be checked with frequency
counter.
72 kHz + 3 kHz to be adjusted with L321 L321
3) Bias frequency to be checked for beat cut position 2 and
position 3.
Position 2 : 70 kHz +3 kHz
Position 3 : 68 kHz + 3 kHz
7
|
Rec/Playback
TS-8
(UR)
Reference
signal
—20
dB
to
be
applied
to
Mic,
and
difference
frequency
level
between
125
Hz
and
8
kHz
against
1
kHz
to
be
checked.
characteristics
1kHz/125
Hz:
—2dB+4dB
Check
1kHz/8kHz
:
+2
dB*§
dB
—_______+
8
|
Maximum
output
|
VTT722
Play
back
VTT722.
Measuring
point
:
Headphone
output
&
Output
more
than
28
mW
(0.95
V)
at
SEA
max.
_|_
Check
10 (No. 1768)