Dokorder 7700 - Page 21

d. Test tape,
special tools
and
instruments
required
Blank tape
(Scotch
#212]r
,
oscilloscope,
signal
generator
and
VTVM.
e. Test
point
Connect
the
VTVM
and
oscilloscope
to
the
line output
jacks.
f
.
Mode of switch
(1)
Tape
speed SW-19
cm/s,
Monitor SW-TAPE,
Equalizer
SW-NORMAL
(button
out),
Record
SW-ON.
(2)
P.B.
level
controls-MAX,
Record
level
controls-MAX.
g.
Procedure
(1)
Connect
the signal
generator
to
the
line
input
jacks,
and
apply
a 700
Hz signal
of
-20
dB to the
line
inputs.
(2)
After
the above
connections
are
completed,
load the blank
tape
(Scotch
#212])
on
the
deck and
push
the
record
button and
play
button simultaneously
to enter the
record
mode.
(3)
Adjust
the trimmer
capacitors
C-604 and
C-606 on the
REC switch
PC
Board
(PCM-397),
so that
the
bias
may
be overbiased
at
+0.3
dB.
(4)
Then
adjust the
semi-fixed
resistors
for
recording level adjustment
VR-102
and
VR-202
on the AMP
PC
Board
(PCM-446),
so that
the
line output
level may
be
0
dB.
2-10
HEAD AZIMUTH
(REC.
Headl
a. Speci{ication
Max.
and
phase
shift
less than
45o.
b. Adjustment
Adjust
the azimuth
screw.
c.
Reference
Refer to
Fig.6-3,
Fig.6-5 or
section
2 on
page
M-20.
d.
Test tape,
special
tools
and
instruments
required
Blank tape
(Scotch
#212]t
,
oscilloscope,
signal
generator
and
VTVM.
e.
Test
point
Connect
the
VTVM
and oscilloscope
to the
line
output
jacks.
f.
Mode of switch
(1)
Tape speed
SW-19
cm/s,
Monitor
SW-TAPE,
Equalizer
SW-NORMAL,
Record
SW-ON.
(2)
P.B. level
controls
MAX, Record
level
controls
MAX'
g.
Procedure
(1)
Connect
the
signal
generator
to
the
line
input
jacks,
and
apply
a 20
KHz signal
of
-30
dB to
the
line
i n
puts.
(2)
After
the above
connections
are
completed,
load the
blank
tape
(Scotch
#212i)
on the
deck
and
push
the
record
button
and
play
button
simultaneously
to enter
the
record
mode.
(3)
Adjust
the
head azimuth
by turning
azimuth
screw,
so
that
the
line output
level
becomes
maximum
and
phase
shift
is less than
45'
by observing
the
lissajous
figure on
the osciiloscope
as shown
FiS.
O-S
on
page
20.
(4)
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'
ADJUSTING
SCREWS
(E
^...'
Op"q,
A:,
FF.ord Fead
PlaVback
Head
Q
.uo*-
o
F is.6 3
U
3
t
18
j