Tektronix 422, Instruction Manual

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Performance Check/Calibration—Type 422 AC-DC
Fig. 5-22. (A) Typical CRT display when checking positive-slope
triggering, (B) typical CRT display when checking negative-slope
triggering.
39. Check Triggering Slope Switch Operation
a. Change the follow ing control settings:
TRIGGERING Coupling AC
T IM E /D IV .2 ms
c. CHECK—Rotate the LEVEL control throughout its
range and check that the display can be triggered (stable
display) at any point along the negative slope o f the wave­
form (indicates LEVEL control range o f at least + and — 10
volts). The display is not triggered at either extreme of
rotation.
d. Set the SLOPE switch to the positive-going position.
e. CHECK—Rotate the LEVEL control throughout its
range and check that the display can be triggered (stable
display) at any point along the positive slope o f the wave­
form (indicates LEVEL control range o f at least + and — 10
volts). The display is not triggered at either extreme of
rotation.
f. Disconnect all test equipment.
41. Check Auto Recovery Time
a. Change the follow ing control settings:
CH 1 VO LTS/DIV .5
TRIGGERING Source CH 1 &
TRIGGERING Coupling AC
TRIGGERING Mode AUTO
T IM E /D IV .5 ms
b. Connect the time-mark generator to the INPUT 1
connector through the 42-inch 50-ohm BNC cable and the
50-ohm BNC termination.
c. Set the time-mark generator fo r 50-millisecond mar­
kers.
d. CHECK—Stable display can be obtained w ith the
LEVEL control.
e. Set the time-mark generator fo r 0.1-second markers.
b. Set the low-frequency sine-wave generator fo r a four-
division display at one kilohertz.
c. CHECK—CRT display starts on the positive slope of
the waveform (see Fig. 5-22A).
d. Set the SLOPE switch to the negative-going position.
f. CHECK—Stable display cannot be obtained at any
setting o f the LEVEL control.
42. Check/Adjust Normal Timing
a. Set the time-mark generator fo r 0.5-millisecond mar­
kers.
e. CHECK—CRT display starts on the negative slope of
the waveform (see Fig. 5-22B).
40. Check Triggering Level Control Range
a. Change the follow ing control settings:
CH 1 VO LTS/D IV 5
TRIGGERING Source EXT
TRIGGERING Coupling DC
LEVEL Midrange
b. Set the low-frequency sine wave generator fo r a
four-division display (20 volts peak to peak).
b. Set the LEVEL control fo r a stable display.
c. CHECK—CRT display fo r one marker each division
between the second and tenth vertical lines o f the graticule
(see Fig. 5-23A). Tenth marker must be w ithin 0.24 divi­
sion (within 3%) o f the tenth vertical line w ith the second
marker positioned exactly to the second vertical line.
NOTE
Unless otherwise noted, use the middle eight hori­
zontal divisions (between second and tenth vertical
lines o f the graticule) when checking or adjusting
timing.
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