Tektronix T921 User Manual

Operating
Instructions-T921/T922/T922R
NOTE
In the following
steps, if you use a 1X probe or
coaxial cable, use the 1X PROBE
window for
VOLTS/DIV settings . If you use a 10X probe (as
supplied with T921 and T922), use the 10X probe
window .
The PROBE ADJ
output is a square wave . An incorrect-
ly compensated probe will
distort the top and bottom of
the signal but will not affect the checks .
If
you
want to compensate a probe, refer to the Probe
Compensation information after this procedure .
1 . Set :

CH 1 VOLTS/DIV

.2 V (10X window)
CH
1 VAR

detent
(fully clockwise)
CH 1 AC-GND-DC

GND
2 . Using the
CH 1 POSITION control, align the trace
with the center graticule
line . If the trace is tilted, adjust the
trace rotation (control marked TR
ROT on the left-cabinet
side of T921 and T922) for the
best alignment of the trace
.with
the center graticule line .
3 . Connect the
Probe to the CH 1 input and hold the
probe tip against the PROBE ADJ
connector . Setthe CH 1
AC-GND-DC switch to DC . You should
haveapproximate-
ly 2 .5 divisions
display . The square wave will
be below the
center line . This
display may or may not be stable .
4 . Set the CH 1 AC-GND-DC switch
to AC . The display
should be approximately equidistant above and below the
center line
.
2- 1 2
NOTE
If
you cannot obtain a display,
remove the probe tip
from
the PROBE ADJ connector .
Touch the tip to
your
hand . Change the VOLTS/DIV
setting if
necessary
to get a display . The display
should be a
thick (vertically)
trace . A thickening trace
indicates
that the probe
is picking up the power line radiation
that your . body
normally picks up . If this occurs, the
vertical is usable but the
PROBE ADJ output isn't . If
the
thickening does not occur, you
have a defective
probe or other
instrument malfunction .
5 . Rotate the CH 1 VAR
control through its range . The
display
amplitude will decrease . Leave the
VAR control
fully clockwise
(detent)-maximum display amplitude
.
6 . Set :

Vertical Mode

CH 2
X-Axis Operation
Astigmatism
Operation
CH 2 VOLTS/DIV

.2 V
CH 2 VAR

detent (fully cw)
CH 2 AC-GND-DC

GND
CH 2 POSITION

To align trace
with center
graticule line
7 .
Connect the probe to the CH 2 input and hold the
probe tip against the PROBE ADJ
connector .
8 . Set the CH 2 AC-GND-DC switch to DC . The square
wave will be below the center line .
9
.
Set the CH 2 AC-GND-DC switch to
AC .
The
square
wave will
be approximately equidistant above and
below
the center
line .
10 . Rotate the CH 2 VAR control through its range . The
display amplitude will decrease . Leave the VAR control
fully
clockwise (in detent) .
11 . Return the vertical
mode switch to CH 1 .
1 . Connect the probe
to
the X input (if
a
1X
probe is
available, use it, if a 10X probe
is used, rotate the X1-X10
control fully clockwise) and hold the probe tip against the
PROBE
ADJ connector .
2 .
Set the SOURCE switch to X-Y, and reduce INTEN-
SITY as necessary .
Adjust the horizontal POSITION
control as needed to locate the display . You
should see 2
dots separated by a distance
dependent on the X1-X10
control setting . Return X1-X10 to X1 (fully
counterclockwise
detent) .
X-Y and Dual
Trace Operation
This mode is usable with
SEC/DIV settings of 1 ms or
slower . Set controls and connect signals as
you would for
independent X-Y or Dual Trace operation .
1 .
Set :

SOURCE

INT
2 . Connect the probe to the CH 1 input and
hold the
probe
tip against the PROBE ADJ connector . Rotate the
LEVEL
control for the most stable display . Adjust the
FOCUS control for the
display with the sharpest edges
both horizontally and
vertically over the entire screen .
Vertical trace thickness
is
typically
more than the horizon-

-'~
tal
but the edges should be equally sharp . This
is easier to
observe at the
"corners" of the signal .
REV .
C
JUL 1977

Tektronix T921 Specifications

General

Brand	Tektronix
Model	T921
Category	Test Equipment
Language	English