Tektronix 7834

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Operating Instructions--7834
Display Focus
This
instrument contains an
automatic-focusing circuit
which maintains optimum focus
for all intensity settings
after a correct setting of the FOCUS
control is established .
The
easiest way to obtain the
correct setting of the FOCUS
control is to set the
READOUT intensity control so that
the readout portion of
the display is clearly
visible . Then
adjust the
FOCUS control for best definition of
the readout
display . If
the instrument does not contain
the Readout
System (Option
1), set the FOCUS control for
best defini-
tion of
the crt display at a low intensity
setting .
Astigmatism-Focus
Adjustments
If
a
well-defined display cannot
be obtained with the
FOCUS control, adjust the
ASTIG adjustment as follows :
NOTE
To
check for proper setting of
the ASTIG
adjustment, slowly turn the FOCUS
control
through the optimum setting .
If the ASTIG
adjustment is correctly set,
the vertical and
horizontal portions of the
display will focus at
the same position of the FOCUS
control . This
setting of the ASTIG adjustment
should be
correct for any display .
1 . Install an amplifier unit
in the LEFT VERT compart-
ment and a time-base unit
in the A HORIZ compartment
.
2 . Set
the VERTICAL MODE switch to
LEFT and the
HORIZONTAL MODE switch to A
.
3 . Connect the output
of a sine-wave generator to
the input
of the amplifier unit .
Set the sine-wave generator
repetition
rate to 1 kilohertz
and the vertical amplifier deflection
factor for a 2-division
display .
4 . Set the time-base
unit sweep rate for 0 .2
millisecond/
division
and the triggering for a stable display .
Set the A
INTENSITY control so the display is at a usable
intensity
level (about
midrange) .
5 .
Turn the FOCUS control fully
counterclockwise and set
the ASTIG adjustment to midrange .
6 . Set
the FOCUS control so the thickness of
the sine-wave
trace is as thin as possible .
7 . Adjust
the ASTIG adjustment so
the width of the sine-
wave
trace is as thin as possible .
8 .
Repeat steps 6 and
7 for the best overall focus .
Beamfinder
The
BEAMFINDER helps to locate
a display that overscans
the
crt viewing area vertically and/or
horizontally . When
the BEAMFINDER button is pressed,
the display is com-
pressed and defocused within
the graticule area . To locate
and reposition an overscanned
display, use the
following
procedure :
1 . Press the
BEAMFINDER push button
while the display
is compressed, change
the vertical and horizontal
deflection
factors until the vertical
deflection is about two
divisions
high and the horizontal
deflection is about four
divisions
wide (the horizontal
deflection needs to be reduced
only
when operating in an X-Y
mode) .
2 . Adjust the vertical and
horizontal position controls
to
center the display on
the graticule .
3 . Release the BEAMFINDER
push button ; the
display
should remain within
the graticule area .
Trace
Alignment
The TRACE ROTATION control
allows the trace to
be
aligned with the horizontal
graticule lines . To set
the
control, position the trace to
the center horizontal line
and
adjust the TRACE ROTATION
control so that the trace
is
parallel with the
center horizontal graticule
line .
Readout
Display
NOTE
Option
1 deletes the Readout
System and
probe power connectors from
the instrument, -
disregard the following information
for Option 1
instruments .
The Readout System provides an
alpha-numeric display of
information on the crt along with
the analog waveform
display . The information displayed by
the Readout System
is obtained
from the plug-in units
installed in the plug-in
compartments .