Sharp VC-780E - Page 26

Yl- OU
| VC-790ET
ADJUSTMENT
OF
SERVO
CIRCUIT
1.
Insert
the
blank
tape
and
put
the
unit
in
the
PAL
LP
Recording
mode.
Adjustment
of
PC
5V
power
supply
2.
Make
sure
that
the
time
“T"
from
the
leading
edge
of
head
switching
pulse
to
the
leading
Measuring
|
vtvu
edge
of
control
pulse
at
TP702
(CTL
PULSE)
is
instrument
P
18.4
+
1
msec.
|
Mode
[PALS
emsPRecring
In
the
PAL
System
SP
Recording
mode,
adjust
R797
so
that
the
voltage
at
TP704
be
5.1
+
0.1V.
= | TP701 H.SW.PULSE
t
!
i
J
t
i:
oe
an
TP702
CTL
PULSE
I
I !
T=18.4 + 1 msec.
Figure 2-3.
Precaution in adjusting the X position
Adjustment of PAL System SP Delay
Measuring Oscilloscope
instrument SEtsScop
|
Adjustment
of
NTSC
System
SP
Delay
Measuring Ae
-|
instrument
scilloscape
/
NTSC SPR i
[Mode
|
PAL
SPRecording
Mode
|
NTScsPRecording
Tape used
:
=
Test
point
;
Test
point
CH1:TP701
H.SW.PULSE
ie
CH1-TP7G1
H.SW.PULSE
CH2:TP702
CTL
PULSE
ne
TENA
ETRPU
LE
Adjusting
point
R757
PAL
SP
Delay
Adjusting
point
R761
NTSC
SP
Delay
1.
Insert
the
blank
tape
and
put
the
unit
in
the
1.
Insert
the
blank
tape
and
put
the
unit
in
the
PAL
SP
Recording
mode.
NTSC
SP
Recording
mode.
2.
Make
sure
that
the
time
"T"
from
the
leading
2.
Make
sure
that
the
time
“T"
from
the
leading
.
edge
of
head
switching
pulse
to
the
leading
edge
of
head
switching
pulse
to
the
leading
edge
of
controf
pulse
at
TP702
(CTL
PULSE)
is
edge
of
control
pulse
at
TP702
(CTL
PULSE)
is
30.2
+
1
msec.
24.0
+
1
msec.
es oe TP701 H.SW.PULSE < 4
TP702 CTL PULSE a er ae TP701 H.SW-PULSE
i
!
J
i
t
I
i
TP702
CTL
PULSE
belfrmere——eT
—|
|
|
T=30.2
+
1
msec.
! i
Figure
2-2.
ss
=
Adjustment of PAL System LP Delay T=24.0 + 1 msec.
Measuring
”
instrument
~
Oscilloscope
PAL LP Recording
HABE
USEC
Blank
tape
Test
point
CH1:TP701
H.SW.PULSE
CH2:TP702
CTL
PULSE
Adjusting
point
R759
PAL
LP
Delay
Specification
T=18.4
+
1
msec.
7
Figure 2-4.
26