Tape Tension Check - Sony AV-3600 Service Manual

3.
Observe
the picture
on
the monitor.
(DO
NOT
USE
A MONITOR
SET
FOR A SHORT
HORI-
ZONTAL AFC
TIME CONSTANT.)
If
the
top
of the picture
is
as
shown by
"A"
in
Fig.
4-7c
(it
appears
as
horizontal
jitter),
adjust
Video Head
B
as follows.
4.
Stop
the Videocorder and remove
the tape.
5.
Position the
B
head
so that the
threaded
adjust-
ing-screw holes are accessible
through the cut-out
in
the
upper head drum. See
Fig. 4-7b.
6.
Install
the adjusting screws into
the threaded
holes
at
either side of the
head base
until
the
tapered part just
touches
the
head
base.
7.
Similarly,
install
adjusting
screws into the
two
threaded holes
at
either side
of the
A
head.
These
two
screws serve
only
as
weights to counter-
balance the head-mounting beam.
8.
Play
back the tape and observe the top of the
picture
shown
at
"A"
in Fig. 4-7c.
9.
Stop the Videocorder. Position
Video
Head B
(identified
by
red paint
on
the outer
edge of the
beam)
to the adjusting position
shown
in
Step
5.
10. First, loosen the
(a)
adjusting
screw about
a
quarter turn counterclockwise and
tighten the
(b) adjusting
screw
a quarter turn clockwise.
See
Fig. 4-7b.
11.
Play back
the tape.
Check
the picture
on
the
monitor
screen.
12. If
the dihedral error does not change,
repeat
Steps
9,
10,
and
1 1
until a
change
is visible.
13.
If
the dihedral error decreases, repeat Steps
9,
10,
and
1 1
until a
normal
picture
is
obtained.
14.
If
the dihedral error increases, reverse the
direc-
tion
of rotation of the
adjusting screws
and
repeat
Steps 9 to 12
until the distortion
in
the
picture
is
minimized.
15.
Thread
a
blank tape
and make
a recording using
a
video
camera
focused
on
a test
pattern (or
using
a telecast test pattern).
16.
Check
the dihedral error
in
the picture
and
trim
up
the position of
Video
Head B
as described
in
Steps 9 to
14.
18.
Remove
the four adjusting screws
from
the head
assembly.
7-inch full reel
tension
arm
spring bracket (A)
Fig. 4-8.
Tape
tension
check
4-6