Tektronix 7B92A Maintenance Manual page 72

j. Check-set the Delayed Triggering SOURCE to
INT and repeat part i of this step.
A11. Check AC LF Reject Operation
a. Disconnect the 50-C cable from the DLY'D
TRIG IN connector and reconnect it to the MAIN TRIG IN
connector.
b. Set the vertical
volts/division switch to 0.5 V.
c. Set the low-frequency sine-wave generator for
an eight-division display at 60 Hz. Center the display
vertically on the graticule.
d. Check-set the MAIN TRIGGERING LEVEL
control for a stable display (TRIG'D light on).
e. Set the MAIN TRIGGERING COUPLING to AC
LF REJ; set the MODE to NORM.
f. Check-for no display (TRIG'D light off) when
the MAIN TRIGGERING LEVEL control is rotated
throughout its range.
g. Set the MAIN TRIGGERING COUPLING to
AC; set the SOURCE to EXT.
h. Reduce the output of the low-frequency sine-
wave generator to provide a six-division display (3.0 V) at
60 Hz. (Adjust the MAIN TRIGGERING LEVEL control
to maintain a stable display.)
i. Set the MAIN TRIGGERING COUPLING to AC
LF REJ and repeat part f of this step.
A12. Check 20 MHz Triggering
a. Set the vertical
volts/division switch to 0.2 V.
b. Set the 7B92A controls as follows:
MAIN TRIGGERING
COUPLING
MAIN TRIGGERING
MODE
MAIN TRIGGERING
amplifier plug-in unit
amplifier plug-in unit
AC
AUTO
INT
Performance Check/Calibration-7B92A
SOURCE
Delayed Triggering
COUPLING, SOURCE
and SLOPE
Delayed Triggering
LEVEL
TIME/DIV OR DLY TIME
DLY'D Time/Division
c. Disconnect the 50-Q cable from the low-
frequency sine-wave generator and connect the medium-
frequency signal generator to the vertical amplifier plug-
in unit input using the 50-n cable.
d. Set the medium-frequency signal generator for
a 0.5 division display (100 mV) at 20 MHz.
e. Check-for a stable display (TRIG'D light on)
with the MAIN TRIGGERING COUPLING switch set to:
(1) AC
(2) AC LF REJ
(3) DC
(Set the MAIN TRIGGERING LEVEL control as
necessary.)
f. Check-change
SOURCE to EXT and repeat part e of this step.
g. Disconnect the 50-C cable from the MAIN
TRIG IN connector and reconnect it to the DLY'D TRIG
IN connector.
h. Set the Delayed Triggering LEVEL control near
"0".
i. Set the MAIN TRIGGERING SOURCE to INT
and MAIN TRIGGERING COUPLING to AC.
j. Check-for a stable display (TRIG'D light on)
with the Delayed Triggering COUPLING switch set to:
(1) AC
(2) DC
k. Set the Delayed Triggering SOURCE to EXT
and repeat part j of this step.
I. Disconnect the 50-C cable from the medium-
frequency signal generator; disconnect the 50-C cable
from the bnc tee at the vertical amplifier plug-in input
connector.
5-22
All pushbuttons in
RUNS AFTER
DELAY TIME
50 ns
5 ns/PULL FOR ALT
the MAIN TRIGGERING