Fig.
41
- Location
of
the ASTIGMA
115M
and
TRACE
ROTATOR controls.
e
SENCORE
"""".
",..-'
•
0
•
•
a---
S~
...
r
....
•
0
•
•
0-.,,--
•
~OeLT,l,ME
•
0
o
e
MODEL 5C61
l
••••
J
\
o
ASTIGMATISM
Fig.
42
- Location
of
the amplifier balance controls.
The
ASTIGMATIS~(
control
.....
orks
in conjunction
....
ith
the
FOCUS control to
product! the
sharpest
possible
trace.
The
A$TIG:\L-\TlS:\l control
compensates
for
minor
changes
in
the
CRT
and
high voltage power supply. The
ASTIG:\L-\T1S:\1
and
FOCUS controls are simply balanced for the
sharpest
trace.
Once the controls
are
balan~,
the
FOCUS
control should ha"e
sufficient range to compensate for variables, such
as
changes
in
brightness. differents
.....
eepspeeds.
etc.
To
adjust the
ASTIGMATIS:\!
control:
1. Set both IZ\'PUT
COUPLI~G
s
....
;tches
to the "ground"
position and depress the VECTOR CRTdispla)' pushbutton.
2.
Adjust the
I~TENSITY
control until a dot
appears
that is
reduced
in
brightness enough to pre,'ent blooming (a halo
around the dot).
3.
Alternately
adjust
the FOCUS
and
ASTIGMATISM controls
until the dot is
as
small
and
round
as
possible.
It
is normal for
the
tV"e
controls to interact,
TRACEBAL
The two TRo\CE
BAL
controls balance
DC
bias of the vertical
amplifien
to insure the
trace
does not move
venically
when
adjustingthe
VOL
TSIDIVlSIONsv.'i.td!es
or
the vertical
vernier
controls. Proper setting of these controls results
in
accurate
measurements
when using the CRT display to
measure
the
DC
le\'el ofa signal.
To
set
theTRACE BAL controls:
l.
Set the TRIGGER MODE s
....
itd!
to
"Auto" to provide a
baseline
....
ith
no
input signal.
2.
Set the channel A l!\'PlIT COlWLI!'G s
....
itch
to
the
"ground"
position
and
depress the
CHAN
A CRT display push·
button.
3.
Set the channel A VOLTS/DIVlSION s
....
itch
to the
",S"
position,
4. Set the channel A vernier control fully counterelockv.'ise.
TRACE
ROTATOR
The TRACE ROTATOR
ensures
the
trace
is parallel to the CRT
graticule markings.
External
magnetic fields (including the
earth's)
affect
every
oscilloscope. If, for example, you move the
SC61
from a north·south to
an
east·west
orientation, the tilt of
the CRT beam changes slightly.
It
is normally not necessar;' to
reset
theTRo\CE ROTATOR control unless the
SC61
is moved to
a ne"
..
location
or
some
change
occurs in the e."ternal magnetic
fields.
5.
Adjust the channel A VERTICAL POSITION control until
the
trace
lies on thehorizontal
center
lineof the CRT.
6. Turn the channel A
vernier
control fully clock
....
ise.
If
there
is any movement of the
trace
away
from the center line,
adjust
theTRACE BAL control until it
returns
to theoriginal position.
7.
Repeat
steps
-l
through 6 until there is no further improve-
ment.
To
set
theTRACE ROTATOR:
1. Set the TRIGGER MODE switch to "Auto"
to
pro\'i.de a
base
line with
no
inputsignal.
2.
Set the channel A
lI'-;"PlJT
COUPLI:\G sv.'i.tch to the
"ground" position
and
depress the
CHAl'\'
A CRT display push·
button.
3.
Adjust the channel A VERTICAL POSITIO:-l control until
the
trace
is
adjacent
to oneof theCRT graticule lines.
8.Repeat
steps
2 through 7for channel
B.
NOTE:
The TRACE BALCOl1trofs
ore
IG-turnpotentiometeu.
INVERTBAL
The II\'VERT BAL control balances the
DC
bias
on
thechannel A
im'erting amplifierto pre\'enta change
in
vertical position when
the
traCi:!
is
inverted. This control should not
be
adjust~
until
the channel A TRACE
BAL
control is properl)' set.
4.
Adjust the TRACE ROTATOR until the
trace
is
parallel to
theCRT graticuJe line.
Toset
the INVERT BALcontrol:
1.
Perionn
the TRACE BAL
adjustment
listed abo\'e. Leave
all front-panel controlsset
as
indicatedin the prevjousproc-eCure.
2.
Press
the
C~V
ACRT selector pushbutton.
29
To Next Page
Loading...
