Dokorder 7700 - Adjustment Procedures

6.2
ADJUSTMENT
PROCEDURES
2-1
HEAD AZIMUTH
(P.8.
Head)
a. Specification
Max.
output
level under
the
signal
in-
phase
cond ition.
b. Adjustment
Adjust the azimuth screw.
c.
Reference
Refer
to
Fig.6-2, Fig.6-5
or section
2 on
page
M-20.
d. Test
tape,
special tools
and instruments
required
DTT-5113
(15
KHz
-10
dB) or
equivalents.
VTVM and oscilloscope.
e. Test
point
Connect the
VTVM and oscilloscope
to the
line
output
jacks.
f . Mode of switch
(1)
Tape speed SW-19
cm/s
(button
out),
Monitor
SW-TAPE
(button
out).
(2)
Playback level controls-MAx,
Record
level controls-MlN.
g.
Procedure
(1)
After
the above
connections are
completed,
load
the test
tape
(DTT-5113)
on the
deck and
push
the
play
button
to
enter
the
playback
mode.
(2)
Adjust the
head azimuth
by turning
azimuth screw, so
that
the
line.
output
level becomes
maximum and
phase
shift
between
both channels
becomes
minimum by observing
the
lissajous
figure on the
oscilloscope
as shown
Fig.6-5
on
page20.
(3)
When the azimuth
adjustment
is completed,
paint-lock
the
azimuth
screw'
h.
Note
Since
head azimuth
is,already adjusted
before the deck
leaves our
Dokorder
factory, normally
azimuth adjust-
ment is
unnecessary;
it is necessary
only
when
heads
are
replaced.
2-2
PLAYBACK
a. Specification
-1
0
dB
r0.5
dB
of the
line output
iacks.
b. Adjustment
Adjust the
semi-fixed
resistors
VR-106
(L-ch)
and
VR-206
(R-ch)'
c.
Reference
Refer to
Fiq. 6-1.
d. Test
tape,
special tools
and
instruments
required
DTT-s106
(700
Hz
-10
dB)
or equivalents
and
VTVM.
e. Test
point
Connect
the VTVM
to the
line output
jacks.
f
.
Mode of switch
(1
)
Tape
speed SW-19
cm/s,
Monitor
SW-TAPE'
(2)
P.B.
level
controls-MAX,
Record
level
controls-M
lN.
g.
Procedure
(1)
After
the above
connection
is
completed,
load
the test
tape
(DTT-5106)
on the
deck and
push
the
play
button to
enter the
PlaYback
mode'
(2)
Adjust
the semi-fixed
resistors
VR-106
and VR-206
on the
AMP
PC
Board
(PCM-446),
so
that
the
line
output
levels of
the deck
are
-10
dB
10.5
dB
on the
VTVM.
q-.
ADJUSTING SCREWS
(E
o,.
,r
S
r"i.h
@
2""
Q..o*-
c
Be.ord
tsead
P;,b.Lr
Hp.d
F iq.6-2
t*
v
14