Sharp VC-780E - Page 17

pi.
ro
NE eS
4.
Slowly
rotate
the
torque
gauge
in
the
CCW
direction
of
the
take-up
brake
so
that
the
reel
disk
and
the
gauge
needle
rotate
at
the
same
speed.
Do
the
same
in
the
CW
direction
of
the
take-up
brake.
Check
that
the
values
are
within
the
specified
range
(CCW
direction
=
280
to
720g.cm,
CW
direciton
=
90
to
200
g.cm)
and
that
the
brake
torque
in
the
CCW
direction
is
at
least
twice
as
high
as
that
in
the
CW
direction.
Take-up reel disk
Torque gauge
Torque gauge
head
Take-up reel disk
Idler gear
{a) side view
Reel pulley
(center gear}
(b) top view
Figure 1-18.
@ Adjustment
1. \f the take-up brake torque is outside the
specified
range
(CCW
direction
=
280
to
720g.cm,
CW direction = 90 to 200 g.cm), clean the take-
up
reel
disk
and
brake
lever
felt,
then
recheck
the torque.
2. If the take-up brake torque is still outside the
specified range, replace the main brake spring.
REPLACEMENT OF A/C (Audio/Control)
HEAD
Note:
After
replacement,
perform
the
adjustment
of
tape
drive
train.
Under
any
circumstances
avoid
touching
the
head
(indicated
by”
3”
in
Fig.
1-
20{c)).
eReplacement (See Figs. 1-19 and 1-20.)
1. Loosen the tilt adjusting screw @ by using
Phillips screwdriver.
2.
Remove
the
azimuth
adjusting
screw
©
with
a
Phillips
screwdriver.
3.
Remove
the
A/C
head
screw
@
with
a
Phillips
screwdriver,
paying
attention
to
the
spring
@
between
the
A/C
head
screw
@
and
A/C
head
pedestal.
Video cassette tape
0.3~-0.5 mm
é
’
Control head Adjust the nut G) so that
the control head is visible
0.3 to 0.5 mm below the
bottom of the tape.
Figure 1-19.
4. Remove the A/C head PWB © soldered to the A/C
head assembly, and solder the A/C head PWB @
onto a new A/C head assembly.
5. The A/C head assembly @ is attached so that the
A/C head arm @ and A/C head pedestal are
roughly parallel to each other.
(6) Azimuth adjusting
screw (2.6P +65)
© Tilt adjusting screw
@ AIC head screw
(a)
Pedestal #
@ AIC head arm
(b)
© Tilt adjusting screw
ge @) AIC head screw
Tightening torque
4+1 kg.cm
(5) Azimuth adjusting
screw
@) Azimuth spring
(@) A/C head PWB
(@) A/C head ass‘y
@ A/C head height
adjusting nut
I
Avoid touching
the head.
‘(@) AIC head arm
(c)
Figure 1-20.
VC-790ET