Tektronix 7B92 Instruction Manual page 31

Calibration-7B92 Service
t. Change the MAIN TRIGGERING SLOPE switch to
(+).
Yu. CHECK-Repeat step s for the positive slope of the
waveform.
v. If the 7892 does not meet the requirements given in
part s, check the adjustment of the Main Trigger Level
Sensitivity (R730-Calibration step 2).
V8.
Check Main Triggering AC LF REJ Operation
a. Change the following control settings:
Volts/Div
Main Triggering
SOURCE
TIME/DIV OR
DLY TIME
7 A 15A Amplifier
1 V
7B92 Time Base
EXT
10 ms
DL Y'D Time/Division 10 ms (press in for
NORMAL Sweep
Display Mode)
b. Set the low-frequency sine-wave generator for a
three-division display (three volts) at 60 hertz.
c. Rotate the MAIN TRIGGERING LEVEL control for
a stable display (TRIG'D light on).
d. Change the MAIN TRIGGERING COUPLING switch
to AC LF REJ.
Ye. CHECK-Rotate the MAIN TRIGGERING LEVEL
control throughout its range and check that a stable display
cannot be obtained (TR IG'D light off).
f. Change the MAIN TRIGGERING SOURCE switch to
INT and the COUPLING switch to AC LF REJ.
g. Set the low-frequency sine-wave generator for an
eight-division display at 60 hertz. Center the display
vertically.
Yh. CHECK-Rotate the MAIN TRIGGERING LEVEL
control throughout its range and check that a stable display
cannot be obtained (TRIG'D light off).
4-10
Scans bv OulsouTce-Options
=>
i. Disconnect all test equipment from the oscilloscope
system.
V9.
Check Line Triggering Operation
a. Change the following control settings:
Volts/Div
Main Triggering
COUPLING
SOURCE
7 A 15A Amplifier
5V
7B92 Time Base
AC
LINE
b. Connect the 10X probe to the 7 A 15A Input and the
probe tip to the same line-voltage source which is
connected to the oscilloscope.
Yc. CHECK-Rotate the MAIN TRIGGERING LEVEL
control and check that a stable display can be obtained
(TRIG'D light on) for both the (+) and (-) SLOPE.
d. Disconnect all test equipment from the oscilloscope
system.
V10. Check AUTO, NORM, and SINGLE SWEEP
Modes
a. Change the following control settings:
7A19 Amplifier
Volts/Div 1 V
7904 Oscilloscope
Vertical Mode Left
7B92 Time Base
Main Triggering
SOURCE
TIME/DIV OR
DLY TIME
DL Y'D Time/Division
INT
10 ps
10 ps (press in for
NORMAL Sweep
Display Mode)
b. Connect the Output of the low-frequency sine-wave
generator to the 7 A 19 Input with a 42-inch 50-ohm 8NC
cable. Set the low-frequency generator for a four-division
display at 50 kilohertz.
c. Rotate the MAIN TRIGGERING LEVEL control for
a free-running display (TRIG'D light off).
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