Tektronix 7D11 DIGITAL DELAY Service Instructions Manual page 41

L
might be necessary to reset the TRIGGER LEVEL control
for a stable display).
Vi. CHECK-Using Table 4-2 as a guide, check for each
condition given in both the
+
and - positions of the
TRIGGER SLOPE switch. It might be necessary to reset
the TR IGGER LEVEL control to obtain a stable display
after changing the coupling or TRIGGER SLOPE switch
setting. Set the time-base unit sweep rate for optimum
viewing of the display.
TABLE 4-2
7011 Generator Display
Stable
COUPLING Frequency Amplitude Display
AC 30 hertz 0.3 division yes
AC HF REJ 30 hertz
0.3 division yes
DC 30 hertz 0.3 division yes
AC LF REJ 120 hertz
3 divisions
no
AC LF REJ
30 kilohertz
0.3 division yes
AC HF REJ 50 kilohertz
0.3 division
yes
j. Disconnect the signal generator.
k. Connect the medium-frequency signal generator to
the amplifier unit.
VI. CHECK-Using Table 4-3 as a guide, check for a
stable display for each condition given in both the
+
and -
TRIGGER SLOPE switch positions. Reset the TRIGGER
LEVEL control as necessary to light the TRIG'D indicator
and obtain a stable display. Set the time-base unit sweep
rate for optimum viewing of the display.
TABLE 4-3
7011 Generator Display
COUPLING Frequency Amplitude
AC 10 megahertz 0.3 division
AC LF REJ 10 megahertz
0.3 division
-~-
DC 10 megahertz 0.3 division
AC
50 megahertz 1.0 division
AC LF REJ
50 megahertz
1.0 division
DC 50 megahertz 1.0 division
m. ADJUST-If necessary, adjust the Delay Start TD
Bias adjustment R 151 for a stable display of the 50-mega-
hertz signal.
REV. B, AUG. 1975
Calibration-7D11 Service
n. Disconnect all test equipment (leave DL Y'D TRIG
OUT connected to the time-base unit for next step).
Y7.
Check External Trigger Sensitivity
a. Set the 7D11 SOURCE switch to EXT and the
COUPLING switch to AC.
b. Connect the low-frequency signal generator to the
amplifier-unit input and to the EXT TRIG IN connector.
c. Connect the DL Y'D TRIG OUT connector to the
time-base unit external trigger input. Set the time-base unit
for a 10 millisecond/division sweep rate.
d. Set the amplifier unit for a calibrated deflection
factor of 50 millivolts/division.
e. Set the signal generator for a three-division display
(150 millivolts) at 30 hertz.
f. Set the 7D11 TR IGGER LEVEL control to light the
TRIG'D indicator. Set the time-base unit trigger controls
for a stable display.
Vg. CHECK-Stable display can be obtained with the
TRIGGER SLOPE control set to the
+
and - positions
(resetting the TRIGGER LEVEL control might be re-
quired).
Vh. CHECK-Using Table 4-4 as a guide, check for each
condition given in both the
+
and - positions of the
TRIGGER SLOPE switch. It might be necessary to reset
the TRIGGER LEVEL control to obtain a stable display.
Set the time-base unit sweep rate for optimum viewing of
the display.
TABLE 4-4
7011
Generator Sine-Wave
COUPLING Frequency Amplitude
AC 30 hertz 150 millivolts
AC HF REJ 30 hertz 150 millivolts
DC 30 hertz 150 millivolts
AC LF REJ 150 kilohertz 150 millivolts
AC HF REJ 50 kilohertz 150 millivolts
i. Disconnect the low-frequency signal generator. Con-
nect the medium-frequency signal generator to the ampli-
fier-unit input and to the EXT TRIG IN connector.
4-9