balanced
with
the
core
in
about
the
same
position
in
each
coil.
Reduce
the
sweep
speed
occasionally
to
check
the
level
of
the
first
one-half
microsecond
of
the
square
wave.
h.
Absence of the
cabinet
panel
causes
a
misadjustment
of
the
first
five
delay
line
trimmers.
After
the
delay
line
has
been
adjusted, place
a
small
piece
of
aluminum,
about
4"
x
8"
,
at
the
front
left
side where
the
cabinet
panel
would
normally
be.
This
will
cause
a
slight
wrinkle
near the
top
left
corner
of
the
square
wave.
Readjust
the
first
five
trimmers, C440-C444,
to
remove
the
wrinkle.
If
desired,
a
special
shield
is
available
from
the
factory
to
provide
the
necessary
shielding.
This
shield
may
be
ordered
by
specifying
part
number
333-362.
i.
Adjust
L391
and
L401
for
a
sharp
corner
without
overshoot.
j.
Adjust
L351
and
L361.
These
coils
affect
the
corner and
leading
edge
of
the
square
wave.
Be
careful
to
leave the
two
coils
balanced.
If
you
are
using
a
Type 105
square-wave
generator
set
these coils
where
a
spike
is
not
even
beginning
to
show.
Otherwise
a
faster
pulse
will
show
an
overshoot.
Trigger-Circuit Adjustments
1.
Triggering
Level Centering
The
TRIGGERING
LEVEL
CENTERING
con
trol
is
located
in
the
top
row
of
controls.
This
control
sets
the
level
of
the
trigger
shaper stage
so
that no
readjustment
of
the
TRIGGERING
LEVEL
control is
required as
the
TRIGGER
SELECTOR
switch
is
changed
from
+
to
-
slope.
a.
Set
the
TRIGGER
SELECTOR
switches
to
+
INT,
AC.
b.
Display
the
calibrator
waveform
with
2
to
4
mm
deflection.
c.
Turn
the
black
TRIGGER
SELECTOR
knob
back
and
forth from
+INT
to
-INT.
Simul
taneously
adjust
the
TRIGGERING
LEVEL
CENTERING
control
and
the TRIGGERING
LEVEL
control
until
no
change
of
either
control is
required
as
the
black
TRIGGER
SELECTOR
knob
is
changed
from
+INT
to
-INT.
2. Internal
Trigger DC
Level
The
INT.
TRIG. DC
LEVEL
ADJ.
control,
R3,
sets
the
triggering level
in
the
DC
position
of
the red
TRIGGER
SELECTOR
knob.
It
is
set
so
the
sweep
will trigger
near
0
on
the
TRIGGERING
LEVEL
control
when
the
trace
is
centered
vertically.
a.
Display
the
calibrator
waveform
with
1
cm
of
deflection
and
the
trace
centered.
b. Turn
the
red
TRIGGER
SELECTOR
knob
to
DC.
c.
Turn
the
TRIGGERING
LEVEL
control
to
0.
d.
Adjust
the
INT. TRIG.
DC
LEVEL
ADJ.
control,
located
near
the
front
of
the
top
chassis,
so
the
sweep
will
trigger
on
either
+
or
-INT
without readjustment
of
the
TRIGGERING
LEVEL control.
3.
Trigger
Sensitivity (SN 101-1000)
The
Trig.
Sensitivity
control,
located in
the top
row
of controls,
adjusts
the
sensitivity
of
the
trigger-shaper
stage.
If
the sweep
triggers
erratically
or
on
the
wrong
slope
it
may
indicate that
this
adjustment
is
incorrect.
a.
Remove
the
vertical
signal.
b.
Turn
the
TRIGGER
SLOPE switch
to
+
LINE.
c.
Set
the
sweep
controls
to
100
gSEC/CM
and
trigger
from
the line.
d.
Turn
the
Trig.
Sens,
control
clockwise
until
the
trace
brightens
abruptly.
This
indicates
that
the
trigger
circuit
is
oscillating.
Now
back
the
control
off
about
45
degrees.
4.
Stability
Preset
Adjustment (SN
1001-up)
The
Preset
Stability
control
sets
the
stability
of the
main
sweep
trigger
circuit in
the
AUTO,
position
of
the
red
TRIGGER
SELECTOR
knob
5-4
Recalibration
Procedure
-
Type
515/515A
AA
