Maximum Deviation Adjustment - Sony AV-3600 Service Manual

5-1.
MAXIMUM
DEVIATION
ADJUSTMENT
(Sync Tip
Carrier
Frequency, Deviation,
Dark
Clip,
&
Video Output
Level)
Test
Point/Board:T?
A05/V2
(Modulator video input)
TP-302/V1 (Limiter output)
TP-305/V1 (Video output)
Adjust
for:
Adjustment/
Board:
Signal
Source-
Equipment
Required:
Set-up:
1.0
V
(p-p)
video
output with
3.2
MHz
to 4.6
MHz
modulator
input.
R126/V2 (Sync
Tip Carrier Fre-
quency)
R137/V2
(White
Clip)
R155/V2
(Dark
Clip)
R121/V2
(Deviation Set)
R335/V1 (Video Output
Level)
(1) Stairstep signal
(2)
Camera
or
telecast signal, pref-
erably a
test
pattern.
(1)
Oscilloscope
(2)
Video
signal
generator
(3)
SONY
Alignment
Tape
See
Fig. 5-1
a.
to
TV
jack
4
4H£J
video
generator
AV-3600
1.0
Vp-p
"itA
Fig. 5-1a.
Maximum
deviation
adjustment
set-up
Procedure
A:
1
.
Play
back
the
SONY
Alignment Tape.
2.
Connect
a
scope to
TP-3
05.
3. Adjust
R335
(Video
Output
Level) for
1.0
volt (p-p).
<4.
Set
up
the E-to-E
mode
with no
input
signal.
5
,
Connect
the scope to
TP-302.
6.
Adjust
R126
(Sync Tip
Carrier Freq.) for 3.2
MHz
as indicated
on
the scope
screen.
3.2
MHz
can be measured
as follows.
a.
Adjust scope time base for 0.5
/isec
per
divi-
sion (calibrated)*.
b.Set scope
controls to obtain a stable trace.
A
correct carrier
frequency of
3.2
MHz
is
indicat-
ed
when
there are
16 complete square
waves
in
ten
divisions.
Set
R126
to
produce
this
indication. See
Fig. 5-2a.
7.
Set
up
the E-to-E
mode
using a
stairstep signal
of
1.0 volt
(p-p).
8.
Connect the scope to TP-305.
9.
Set
R121
(Deviation Set) to
produce
1.0
volt
(P-P).
10. Set
up
the E-to-E
mode
using a
telecast signal,
preferably a
test pattern.
11.
Connect the scope
to
TP-105.
Set the
time base
to 2
msec/cm.
12.
(Omit
this
step for these
sets
having
a serial
number
below
10,550, as these
machines
are
not
equipped with Dark
Clip
Adjustment R155).
Adjust
R155
so that the negative spike
in
the
vertical
blanking pulse faUs
50%
below
sync tip
amplitude. See Fig. 5-lb.
13.
Adjust
R137
(White Clip) so that
extreme peak-
white parts of
the
waveform
are
A+
—
volts
(p-p) as
shown
in Fig.
5-lb
TP-105
v
j__Ll.
-
V(5096)
V-
JL
V(
T
"A"V
"-YV(5096)
-60
Hz-
Fig.
5-
1b.
White
clip
and
dark
dip
ieveis
* Check
the scope
time-base calibration
before matirig
this
adjustment.
5-2