Technics RS-D225W - Page 13

M@ MEASUREMENT AND ADJUSTMENT METHODES
¢
Adjustment
point
VR902
(Mechanism
(1))
VR904
(Mechanism
(1))
VR7,
8
Tape
[2]
Overall
Gain
Adj.
VR901
(Mechanism
(2))
VR903
(Mechanism
(2)
Output
Point
High
Tape
Speed
Adj.
Normal
Tape
Speed
Adj.
TP6 Overall Gain Adj.
Main P.C.B.
Input Point
VR3, 4
Tape [2] P.B. Gain Adj.
VR1, 2
Tape [1] P.B. Gain Adj.
TP1 (Mechanism (1))
TP2 (Mechanism (2))
TPN1 (Mechanism (1))
TPN2 (Mechanism (2))
VR301, 302 Tape [2] Bias Current Adj.
Mechanism (14), (2) P.C.B.
Measurement Condition
¢Input level controls; Maximum
¢ Dolby NR switch; Out
¢ Editing switch; off
*
Editing
tape
speed
switch;
x1
Make sure heads are clean
Make sure capstan and pressure roller are clean.
e Judgeable room temperature 20+5°C (68+9°F)
Measuring instrument
EVM (Electronic Voltmeter)
* Oscilloscope
¢ Digital frequency counter
¢ AF oscillator
ATT (Attenuator)
¢DC voltmeter
e Resistor (600Q)
Test tape
*Head
azimuth
adjustment
(8kHz,
—20dB);
QZ2ZCFM
¢
Playback
gain
adjustment
(315Hz,
0dB);
QZZCFM
¢Tape
speed
adjustment
(3kHz,
—10dB);
QZZCWAT
¢
Overall
frequency
response,
Overall
gain
adjustment
* Normal
reference
blank
tape;
QZZCRA
* CrO, reference blank tape; QZZCRX
+ Metal reference blank tape; QZZCRZ
* Playback frequency responce (315Hz, 12.5kHz,
10 kHz, 8kHz, 4kHz, 1kHz, 250Hz, 125Hz, 63Hz,
—20dB); QZZCFM
Head
azimuth
adjustment
(TAPE
[1,
[2))
1.
Test
equipment
connection
is
shown
in
Fig.
1.
2.
Playback
the
azimuth
adjusted
part
(8kHz,
—20dB)
of
the
test
tape
(QZZCFM)
and
regulate
the
angle
adjusting
screw
so
that
Pores
the
outputs
of
L-CH
and
R-CH
are
maximized.
Fig.
2
(When
the
adjusting
positions
are
different
with
L-CH
and
R-
CH,
find
a
position
where
the
outputs
of
L-CH
and
R-CH
are
balanced,
and
then
make
the
adjustment.)
Fig.
1
3.
At
the
same
time,
draw
a
lissajous
waveform
and
eliminate
phase
deflection.
4.
After
adjustment,
lock
the
tape
guide
height
and
angle
adjustment
screws.
Output point
Tape
speed
adjustment
(TAPE
[1,
[2))
Normal speed
1. Test equipment connection is shown in Fig. 3.
2.
Playback
the
middle
part
of
the
test
tape
(QZZCWAT).
3.
Adjust
TAPE
[1]:
VR904
and
TAPE
[2]:
VR903
so
that
the
output
is
within
the
standard.
Output point
High speed
|
4.
Set
the
editing
speed
switch
to
“x2”
and
short
the
TAPE
[1]:
TP1
and
TPN1
and
TAPE
[2]:
TP2
and
TPN2.
5.
Playback
the
middle
part
of
the
test
tape
(QZZCWAT).
6.
Adjust
TAPE
[1]:
VR902
and
TAPE
[2]:
VR901
so
that
the
output
is
within
Fig.
3
the
standard.
Oigital frequency
counter
i
Standard
value:
3000-+20Hz
(Normal)
6000
+
40
Hz
(High)
Playback frequency response (TAPE [i], [2))
1. Test equipment connection is shown in Fig. 4. +6aBt dt +
2.
Playback
the
playback
frequency
response
part
(315Hz,
+448
t
a
=
12.5kHz~63Hz,
—20dB)
of
the
test
tape
(QZZCFM).
+2dB}——--
=
{5
pope
:
3.
Check
that
the
frequency
is
within
the
range
shown
in
Fig.
5
0d8;—-++
be
>
ances
eee
ne
for
both
L-CH
and
R-CH.
~
248}
—-
4
a
=
Hy
in I \
yt :. aa (|
Output Point oi Ht t+ a rr a
—6dBb-——+ ;
i |!
14 Li i
63H2z 100Hz 315Hz Tr kHz 2kHz 4kHz 8kHz 12.5kHz
Fig. 5 200Hz 500Hz
Fig. 4
Playback gain adjustment (TAPE [1], [2))
1. Test equipment connection is shown in Fig. 4.
2.
Playback
the
playback
gain
adjusted
part
(315Hz,
0dB)
of
the
test
tape
(QZZCFM).
3.
Adjust
TAPE
[1]:
VR1
(L-CH)
{VR2
(R-CH)}
and
TAPE
[2]:
VR3
(L-CH)
{VR4
(R-CH)}
so
that
the
output
is
within
the
standard.
i
Standard
value:
0.4.0.5dB
(0.02v)
|
Overall frequency response (TAPE [2))
1. Test equipment connection is shown in Fig. 6, and connect a
jumper of TP6. (See page 9).
2.
Set
a
normal
blank
tape
(QZZCRA)
and
record
by
applying
signal
(50Hz,
100Hz,
200Hz,
500Hz,
1kHz,
4kHz,
8kHz
and
10kHz),
20dB
attenuated
from
the
reference
input
level
signal
i
(1
kHz,
—24dB).
AF
oscillator
3.
Playback
the
signal
recorded
in
step
2,
and
check
that
the
Fig.
6
level
of
each
output
frequency
is
within
the
range
shown
in
Fig.
7
in
comparison
with
the
reference
frequency
(1
kHz).
4.
If
it
is
not
within
the
standard
range,
adjust
the
bias
current
by
VR301
(L-CH)
{VR302
(R-CH)}
so
that
the
frequency
level
is
within
the
standard.
«Level
up
in
high
frequency
range...........
Increase
the
bias
current.
+
Level
down
in
high
frequency
range...
Decrease
the
bias
current.
5.
After
that
increase
the
signal
recorded
on
CrO,
blank
tape
(QZZCRX)
and
metal blank
tape
(QZZCRZ)
up
to
12.5kHz
and
adjust
in
the
same
way
as
mentioned
above
and
check
that
the
frequency
level
is
within
the
range
shown
in
Fig.
8.
6. After adjustment, cut a jumper of TP6.
Input Point
T
7
Py
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i
50HZ
100Hz
200H2
SOOHz
1kH?
2kHz
4kHz
10kHz
S0Hz
100Hz
200Hz
500H2
tkHz
2kHz
4kHz
8kHz
12.5kHz
Fig.
7
Fig.
8
Overall gain adjustment (TAPE [2))
.
Test
equipment
connection
is
shown
in
Fig.
6,
and
connect
a
jumper
of
TP6.
(See
page
9.)
Set
a
normal
blank
tape
(QZZCRA)
and
apply
the
reference
input
level
signal
(1kHz,
—24dB)
in
record
pause
mode.
.
Adjust
the
output
0.4V
by
attenuator
and
then
record.
.
Playback
the
signal
recorded
in
step
3,
and
check
that
the
output
is
within
the
standard.
.
If it
is
not
within
the
standard,
adjust
VR7
(L-CH)
{VR8
(R-CH)}
and
repeat
the
step
(2),
(3)
and
(4)
until
the
output
is
within
the
standard.
6. After adjustment, cut a jumper of TP6.
Ow mo
ie : + 0.1
| Standard value: 0.4V | y08Y |
Dolby NR circuit
1. Test equipment connection is shown in Fig 9.
2. Set a normal tape and apply 5kHz signal in record pause
mode.
3.
Adjust
by
attenuator
so
that
the
output
between
terminal
©
|.
OHS
(L-CH)
{terminal
@
(R-CH)}
of
1C401
and
ground
is
12.3MV.
AF
oscailiator
4.
Turn
NR
switch
ON,
and
check
that
the
level
changes
as
specified
from
the
level
in
NR
out
mode.
Fig.
9
[ Standard value: 8+1.5dB
m@ MICRO
(IC801:
Terminal
No.
fe i
= =
= N