c.
Change the following control settings:
VOLTS/DIV
(CH
l and
CH
2)
MODE
TRIGGER
COUPLING
(A
and
B)
HORIZ
DISPLAY
20mV
CH
2
CH
l
ONLY
DC
EXT
HORIZ
d.
Increase the
INTENSITY
control setting
until
the display
is
visible
(two
dots about
five
divisions apart).
e.
Move the display to the center
of
the graticule
with
the Channel l
POSITION
control.
f.
CHECK-CRT display
for
five
divisions
+0.25
division
horizontal deflection.
g.
ADJUST-Ext
Horiz
Gain adjustment,
R645
(see
Fig.
5-41
B),
for
five
divisions horizontal deflection.
62. Check External Horizontal Operation
·a.
Set the B
SOURCE
switch to
EXT.
b.
Connect the standard amplitude calibrator to the
EXT
HORIZ
input connector
(B
EXT
TRIG
INPUT).
c.
Set the standard amplitude calibrator for a two-volt
square-wave output.
d.
CHECK-CRT display for horizontal deflection be-
tween
6.5
and 8.7 divisions
(270
millivolts/division, + 15%).
e.
Set the standard amplitude calibrator for a 20-volt
square-wave output.
f.
Set the B
SOURCE
switch
to
EXT
-:-
l
0.
,g.
CHECK-CRT display for horizontal deflection between
6.2
and
9.2
divisions
(2.7
volts/division,
+20%).
h.
Disconnect all test equipment.
63.
Check
X-Y
Phasing
a.
Connect the constant-amplitude sine wave generator
to the Channel
l and 2
INPUT
connectors through the
five-
nanosecond
GR
cable,
50-ohm
in-line
termination and the
dual-input coupler.
b.
Change the following control settings:
CH
l
VOLTS/DIV
CH
2
VOLTS/DIV
B
SOURCE
lOmV
50mV
INT
c.
Set the medium-frequency generator for a l
0-d
ivision
horizontal display
at
50
kilohertz.
d.
Center the display vertically and horizontallly
with
the
Channel
l and 2
POSITION
controls.
©
Performance Check/Calibration-Type
453/1453
Fig.
5-41.
Location
of
Ext Horiz
Gain
adjustment
( B
Sweep
circuit
board).
0.52
division
or
less
Fig.
5-42.
Typical
CRT
display
when
checking
X-Y
phasing.
e. CHECK-CRT display for an opening
at
the center
hori-
zontal
line
of
0.52
division or
less
(3°
or
less
phase
shift;
see
Fig. 5-42).
64. Check X Bandwidth
in
External Horizontal
Mode
·a.
Disconnect the dual-input coupler
from
the Channel 2
INPUT
connector.
b.
Set the medium-frequency generator
for
a six-division
horizontal display
at
its
reference frequency
(50
kHz).
c.
Without changing the output amplitude, increase the
output frequency of the generator
until
the horizontal deflec-
tion
is
reduced to 4.3 divisions
(-3
dB
point; see
Fig.
5-43).
d.
CHECK-Output frequency
of
generator
must
be
five
megahertz or higher.
5-39
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