Operating instructions
Performance
Check
and
Adjustment
711387
V
d
.
CHECK---Set
the
TRIGGERING
LEVEL
control
for
a
stable
display
(TRIG'D
light
on)
.
J
e
.
CHECK---For
a
free-running
display
with
TRIG'D
light
off
when
the
TRIGGERING
LEVEL
control
is
set
fully
clockwise
and
fully
counterclockwise
.
f
.
Set the
TRIGGERING
MODE
to
NORM
.
J
g
.
CHECK---Set
the
TRIGGERING
LEVEL
control
for
a
stable
display
(TRIG'D
light
on)
.
J
h
.
CHECK-For
no
display
(TRIG'D
light
off)
when
the
TRIGGERING
LEVEL
control
is
set
fully
clockwise
and
fully
counterclockwise
.
i .
Set the
TRIGGERING
LEVEL
control
for
a
stable
display
(TRIG'D
light
on)
.
j
.
Set
the
TRIGGERING
MODE
to
SINGLE
SWP
and
the
SOURCE
to
EXT
.
J
k
.
CHECK-Press
the
SINGLE
SWP
RESET
pushbutton
and
check
that
the
READY
light
is
on
.
,/
I .
CHECK---Rotate
the
oscilloscope
intensity
control
clockwise
slightly
and
check
for
one
sweep
and
that
the
READY
light
is
out
after
completion
of
that
sweep
when
the INT
SOURCE
push
button
is
pressed
.
m
.
Remove
signal
connection
.
V
A3
.
CHECK
EXTERNAL
LEVEL
RANGE
5-6
a
.
Connect
the
low-frequency
sine-wave
generator
to
the
EXT
TRIG
IN
connector
with
a 42-inch
50-ohm
cable
and
T
connector
.
Connect
the output
of
the
T
Connector
to
the
amplifier
unit
input
with an
18-inch
50-ohm
cable
.
b
.
Set
the
TRIGGERING
MODE
to
AUTO,
SLOPE
to
(+),
and
SOURCE
to
EXT
.
SET
the
TIME/DIV
switch
to
0
.5
ms
and
the
EXT
TRIG
IN
attenuator
to
IN
-
1
.
c
.
Set the
amplifier
unit deflection
factor
for
0
.5
volts/division
.
Set
the
low-frequency
sine-wave
generator
for
a
6-division
display
(3
volts)
at
1
kilohertz
.
V
d
.
CHECK--That
all
levels
of
the
positive
slope
may
be
selected
for
the
sweep
starting
point
as the
TRIGGERING
LEVEL
control
is
rotated
throughout
its
range
(indicates
an
external
level
range
of at
least
plus
and
minus
1
.5
volts)
.
Check
that
the
display
is
not
triggered
at
either
end
of
the
LEVEL
control
rotation
.
J
e
.
CHECK----Change
the
TRIGGERING
LEVEL
to
(-)
and
repeat
part
d
for
the
negative
slope
of
the
waveform
.
J
Performance
Requirement
check
;
see
introductory
information
.
A4
.
ADJUST
TRIGGERING
SENSITIVITY
(R49)
a
.
Set
the
TRIGGERING
LEVEL
control
to
0
.
Set the
TRIGGERING
MODE
to
NORM,
and
SOURCE
to
INT
.
b
.
Set the
amplifier
unit
deflection
factor
to
50
millivolts/division
.
Set
the
low-frequency
sine-wave
generator
for
a
5-division
display
(250
millivolts)
at
1
kilohertz
.
c
.
Set the
amplifier
unit
deflection factor
to
1
volt/division
(0
.25
division)
.
Set the
TRIGGERING
LEVEL
control
for
a
stable
display
.
d
.
ADJUST----R49
(Trigger
Sensitivity)
for
a
stable
crt
display
.
e
.
Set
the
amplifier
unit deflection
factor
to
2
volts/division (0
.125
division)
.
Set the
TRIGGERING
LEVEL
control
for
a
stable
display
(stable
display
may
not
be
possible)
.
f
.
ADJUST---R49
(Trigger
Sensitivity)
to
a
setting
that
provides
a
visible
trace,
but the
display
remains
unstable
.
g
.
Repeat
part
c
of
this
step
.
h
.
Set the
amplifier
unit
deflection factor
to
5
volts/division (0
.05
division)
.
J
i .
CHECK----rotate
the
TRIGGERING
LEVEL
control
throughout
its
range
and
check
for
no
trace
(one
displayed
sweep
will
occur
when
control
passes
the
midrange
point)
.
V
A5
.
CHECK
EXTERNAL
TRIGGERING
SENSITIVITY
a
.
Remove
the
7887
and
plug-in
extender
;
then
install
the
7B87
directly into
the
B
horizontal
compartment
.
Set
the
amplifier
unit
deflection
factor
for
10
millivolts/division
.
Set the
low-frequency
sine-wave
generator
for
a
5-division
display
(50
millivolts)
at
30
hertz
.
b
.
Set
TRIGGERING
SLOPE
to
(+)
MODE
to
NORM,
TIME/DIV
to
20
ms, and
set
the
LEVEL
control
for
a
stable
display
.
V
c
.
CHECK----Set
the
TRIGGERING
MODE
to
AUTO
and
check
for
a
stable
display
(TRIG'D
light
on)
with
the
COUPLING
pushbutton
set
to
:
1
.
AC
2
.
AC
HF
REJ
3
.
DC
(Set
TRIGGERING
LEVEL
control
as
necessary)
.