Free-Running Speed Check; Vertical Sync Separator Check - Sony AV-3600 Service Manual

6-1.
FREE-RUNNING SPEED
CHECK
This
test
shows
if
the
Rotary-Head Assembly
rotates
at
the correct speed without
servo correction.
Test Point
1
Board: TP-412/SV
(Shaped 30
PG
pulse
output)
Adjust
for:
30.25
Hz
to
30.35
Hz
Adjustment:
Check
the
Rotary
Head
Drum
Belt
or
refer to a
SONY FACTORY
SERVICE BRANCH.
Signal Source:
None
required
Equipment
Required:
(1)
Frequency
counter
Procedure
A:
1.
Unsolder
the
brake
coil
lead (red)
where
it
connects to TP-41
1
on
the
SV
Board.
2.
Set>up the E-to-E
mode.
3.
Connect
a
frequency counter
to
TP-41
1.
4.
Check the
drum
speed.
The
counter reading
should
be 30.25
Hz
to
30.35 Hz.
5. If
it
is
not
correct,
inspect the Rotary-Head-
Drum
Belt.
Other
causes
of
incorrect free-running
speed should be
referred to a
SONY FACTORY
SERVICE BRANCH.
6-2.
VERTICAL SYNC SEPARATOR CHECK
The
test
checks
the
output of
the
sync
separator.
Test Point/
Board: TP-404, TP-405,
TP-406/SV
Check:
Waveforms shown
in Fig. 6-1.
Adjustment:
None
Signal Source: Telecast
signal
Equipment
Required:
(1)
Oscilloscope
(2)
TV
monitor
Procedure:
1.
Set
up
the E-to-E
mode
using
a telecast signal.
2.
Connect the scope
to
TP-404, TP-405, and
TP-406
and check
that the
waveforms shown
in
Fig. 6-1 are correct.
3.
If
they
are incorrect,
check and
troubleshoot
the sync separator
circuit.
Tr-404
****
IT
60
Hz
•
r
t
4
V
(p-p)
i
TP-405
n
11
i
\1
V
(p-p)
or
more
r
f
t
15
±2
V
(p-p)
Fig.
6-
1.
Sync
separator check
6-3.
2:1
FREQUENCY
DIVIDER
CHECK
Test Point/
Board:
Adjust
for:
Adjustment/
Board:
TP-407/SV
(Separated sync
pulse/
CTL
pulse)
The
waveform shown
in Fig. 6-2.
R433/SV
(30
Hz
adjustment)
Signal
Source:
Telecast Signal
Equipment
Required:
(1)
Oscilloscope
(2)
TV
monitor
Procedure:
1.
Set
up
the E-to-E
mode
using a
telecast signal.
2.
Connect
the scope to TP-407.
3.
Adjust
R433
so that
the
interval
"T"
in Fig.
5-2
is
9
±
1
msec.
4.
Confirm
that pulse amplitude
is
15
±2
volts
as
shown
in Fig. 6-2.
TP-407
t5±2V
T=9
± 1ms
Fig. 6-2.
Frequency
divider
check
6-2