Sony AV-3600 Service Manual page 49

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CH
1
(TP-304J
Uf
u
If
r*V/Vl
If
I
rwi
if
vertical
sync
CH2
(FF
-401 Pin
1)
"T"
'8±0.5H~
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Fig. 6-7.
30
PG
coil
position
Check:
FF-401 Pin
1/SV (Wave-shaped 30
PG
output)
8±
0.5
H
phase difference
See
Fig.
6-7
Adjustment:
30
PG
Coil
A
Signal
Source:
Equipment
Required:
Alignment Tape
(1)
Oscilloscope
(2)
SONY
Alignment
Tape
Procedure:
1
.
Play
back the
SONY
Alignment Tape.
2.
Connect
a
dual-trace
scope
CH-1 probe
to
TP-304
and
CH-2 probe
to
Pin
1
of
FF401
Set
the time base to
2
ms/cm
and the
MODE
select
switch to
CHOP.
3.
Sync
the scope externally
from TP-403.
4. Pull
out the
5X
magnifier
and
adjust
the
POSI-
TION
control to
observe the
second
vertical
blanking
interval as
shown
in Fig. 6-7.
5.
Check
that
the interval
"T" shown
in Fig.
6-7
is
8
±
0.5
H
(horizontal lines).
6.
If it is
correct,
proceed to the
"30 PG PULSE
PHASE CHECK"
in Sec.
6-9.
If it is
not
correct,
reposition
30
PG
Coil
A, which
is
mounted
at
the front
of the scanner, at
the
six
o'clock
position.
See Fig. 6-8.
Be
sure
the
motor
is
off
when making
this
adjustment.
Proceed as follows.
7.
Stop the
motor
(release
the
RECORD
button)
and
allow the heads
to stop turning.
£.
Loosen the screw securing
30
PG
Coil
A, and
9.
Fig. 6-8.
30
PG
Coils
A
and
B
reposition the
coil. If
"T"
in Fig.
6-7
is
more
than 8
±
0.5
H,
move
the
coil slightly
to the
Left
(in
the direction of scanner rotation). If
"T*
is
less
than
8
±
0.5
H,
move
the
coil
to
the
right.
Be
very
careful
when
adjusting
coil
position.
Make
sure that the
gap between
the coil
poles
and
the
rotating
pole piece remains the same.
Also,
make
sure that the
coil
poles
and the
rotat-
ing
pole pieces
line
up
when
viewed
from
abo^ve.
Before turning
on
the
motor
again,
rotate
the
video heads
by hand
to
check
that
the pole
piece clears
both 30
PG
coils.
10. Start
the
motor
again
and check
the
waveform.
11.
Repeat Steps
5 to
10
until the
interval'T'of
8
±
0.5
H
is
achieved.
es