Tektronix 7B92 Instruction Manual page 30

n. CALIBRATION-If the 7B92 does not meet the
requirement given in parts j and m, check the adjustment of
the Delayed Trigger Level Sensitivity (R920-Calibration
step 4).
Y7.
Check Delayed and Main Triggering External
Level Range
a. Install the 7A15A Amplifier into the Right Vert
compartment of the 7904 oscilloscope. Set the oscilloscope
Vertical Mode switch to Right.
b. Remove the BNC T-connector and connections from
the 7 A 19 I nput and connect it to the 7 A 15A Input.
c. Set the 7 A 15A Input Coupling switch to DC and the
Volts/Div switch to 1 V.
d. Change the following control settings:
TlME/DIV OR
DLY TIME
DL Y'D Time/Division
Main Triggering
LEVEL
SLOPE
TERM
Delayed Triggering
SOURCE
SLOPE
20 J.is
10 J.is (Press in for DL Y'D
Sweep Display Mode)
Adjust for TRIG'D
. light on
(+)
IN-1 M.Q
EXT
(+)
e. Set the low-frequency sine-wave generator for a five
division display (5 volts) at 50 kilohertz. Center the display
vertically.
Vf. CHECK-Rotate the Delayed Triggering LEVEL
control throughout its range and check that all levels of the
positive slope may be obtained (indicates an external
delayed trigger level range of at least plus and minus 2.5
volts). CHECK that display is not triggered at either end of
the LEVEL control rotation. (The negative end of the
Delayed Triggering LEVEL does not include the HF SYNC
area ).
g. Change the Delayed Triggering SOURCE switch to
(-).
Vh. CHECK-Repeat step f for the negative slope of the
waveform.
®
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Calibration-7B92 Service
i. CALIBRATION-If the 7B92 does not meet the
requirements given in part f, check the adjustment of the
Delayed Trigger Level Sensitivity (R920-Calibration step
4).
j. Remove the BNC connector from the DL Y'D TR IG
IN connector and connect it to the MAIN TRIG IN
connector.
k. Press the Delayed Triggering LEVEL control to
IN-RUNS AFTER DL Y TIME and pull out the DLY'D
Time/Division switch for the INTEN Display Mode. Set the
MAIN TRIGGERING SOURCE switch to EXT.
I. Set the low-frequency sine-wave generator for a seven
division display at 50 kilohertz. Center the display
vertically.
Vm. CHECK-Rotate the MAIN TRIGGERING LEVEL
control throughout its range and check that all levels of the
positive slope may be obtained (indicates an external main
triggering level range of at least plus and minus 3.5 volts).
Check that display is not triggered at either end of the
LEVEL control rotation.
n. Change the MAIN TRIGGERING SLOPE switch to
(-).
yo. CHECK-Repeat step m for the negative slope of
the waveform.
p. CALIBRATION-If the 7B92 does not meet the
requirements given in part m, check the adjustment of the
Main Trigger Level Sensitivity (R730-Calibration step 2).
q. Change the MAIN TRIGGERING SOURCE switch to
EXT 710.
r. To check EXT 710 external level range, apply a
70-volt peak to peak signal through an attenuator, to the
7A15A Input and to the MAIN TRIG IN connector
(non-attenuated ).
Vs. CHECK-Rotate the MAIN TRIGGERING LEVEL
control throughout its range and check that all levels of the
negative slope may be selected (indicates EXT 710 external
main triggering level range of at least plus and minus 35
volts). Check that display is not triggered at either extreme
of LEVEL control rotation.
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