a.
Connect
a
voltmeter
having
a
resistance
of
5000
ohms
per
volt
or
higher, from
terminals
24
or
25
of
the
power
trans
former
to
ground.
b.
Adjust
the
-1675
ADJ.
control
located
at
the
rear
of
the upper
chassis,
accessible
from
the
right,
to
obtain
a
reading
of
1675
volts.
CRT Geometry
Adjustment
The
GEOM
ADJ. control,
located in
the
top
row
of controls,
varies
the
crt
second
anode
voltage
to
obtain
the
best
possible
linearity
near
the
edge
of
the
graticule.
a.
Set
the
TIME/CM
switch
to
.5
MILLISEC.
b.
Display
the calibrator waveform
at
a
high amplitude so
that the
top
and
bottom
of
the
waveform
are
beyond deflection
plate cutoff.
c.
Adjust
the
GEOM.
ADJ.
control
so the
vertical
lines
near
the edge
of
the
graticule
are straight.
Calibrator
Adjustment
When
the
CALIBRATOR
switch
is
turned
to
OFF, the
calibrator
cathode
follower,
V570B,
remains
conducting
at
the current
required
to develop 100
volts
across
the voltage
divider.
The
CAL.
ADJ.
control, located
just
behind
the
CAL.
OUT
connector,
allows
this
voltage
to
be
set
accurately
to
100
volts.
Be careful
to
use
an
accurate
meter
as
the
accuracy
of
the
calibrator
can
be
better
then
3
per
cent
if
accurately
set.
a.
Turn
the
calibrator
control
to
OFF.
b.
Connect
the
meter
from ground
to
the
pin
jack
labeled CAL.
TEST
POINT,
located
behind the
CALIBRATOR
switch.
c.
Adjust
the
CAL.
ADJ.
control
for
100
volts.
Vertical-Amplifier
Adjustment
1.
DC
Balance Adjustment
The need
for
adjustment
of
the
DC
BAL
control
is
indicated
by
a
shift
in
the
position
of
the
trace
as the
VARIABLE control
is
rotated.
This
is
caused
by
tube
aging
and
the
resultant
shift
in operating
potentials.
a.
Rotate
the
VARIABLE
VOLTS/CM
con
trol
back
and
forth.
b.
Adjust
the
DC
BAL.
control until
the
trace position
is
no
longer
affected
by
rotation
of
the
VARIABLE
control.
2. Gain
Adjustment
Aging
of
tubes
will
also
affect
the
gain
of
the amplifier.
The
GAIN
ADJ.
control
is
accessible
from the
top
side
of
the
lower
chassis
just in
front
of
the
vertical
delay
line
section.
This
control
allows
the amplifier
gain
to
be
set
to
agree
with
the
front-panel
calibration.
a.
Set
the
VOLTS/CM
controls
to
.05,
CALIBRATED. (.I, CALIBRATED,
Serial
Numbers
101-1000).
b.
Display
a
calibrated
waveform
of
.2 volts.
(.5
volts
Serial
Numbers
101-1000).
c.
Adjust
the
GAIN
ADJ.
control
until
the
displayed
waveform
is
four
graticule
divisions
high.
Attenuator
Adjustments
The
need
for
adjustment
of
the
input
atten
uators
is
determined
by
observing
the
response
to
a
1-kc
square
wave.
There
are
two
types
of
adjustment
to
be
made.
One
is to
com
pensate
the
attenuators
so
the
ac
attenuation
is
equal
to
the
de
attenuation.
This
involves
a
moderately short
time
constant
and
can
be
recognized
as
a slight
rounding
or
overshoot
at
the
leading
corner
of
a
1-kc
square
wave.
The
other
type of
adjustment
is
to set the input
capacitance
equal
in
all
positions
of
the atten
uator.
When
the
probe is
connected,
misadjust
ment
can
be
recognized
as
a
downward
or
upward
slope
of
about
the
first
one-half
of
the
1-kc square
wave.
For
best results,
the
attenuator
adjustment
should
be
made
with
a
square-wave
generator
having
a
short
risetime,
such
as
the
Tektronix
Type
105.
An
approximate
adjustment
can
be
made
by
using
the
calibrator
waveform,
but
it
is easy
to
overcompensate
the
attenuator
when
using
this
waveform
because
of
its
longer
risetime.
5-2
Recalibration
Procedure
-
Type
515/515A
AA