Tektronix 7A19 Instruction Manual page 21

1 . Trigger Balance Check/Adjust
a. Interchange the + signal line (A-11) with the + trigger
line (A-13) in the plug-in extender .
b . Interchange the -- signal line (B-11) with the ---
trigger line (13-13) in the plug-in extender .
c. Check-for less than 0.5 division vertical trace shift
while switching the POLARITY switch between +UP and
INVERT .
d . Adjust--the Trigger Bal control for minimum vertical
trace shift as the POLARITY switch is alternated between
+UP and INVERT .
e. Reconnect the signal and trigger lines to their proper
connectors in the plug-in extender .
2. Balance Check/Adjust
a. Check---for less than 0.5 division vertical trace shift
while switching the POLARITY switch between
-f
UP and
INVERT .
b . Adjust-the Bal control for minimum vertical trace
shift as the POLARITY switch is alternated between +UP
and INVERT .
c. Set the POLARITY switch to +UP .
3. Common Mode Check/Adjust
a. Disconnect the signal lines from the plug-in extender
(A11 and 1311 BNC cables) and short the signal lines
together using a BNC
"T . adapter . Connect
the "T"
adapter to the Vertical plug-in unit via the BNC female to
BNC female adapter and the 42 inch BNC cable .
b. Set the calibration oscilloscope Vertical Mode to
Right. Set the vertical plug-in unit to obtain 50 mV/division
DC sensitivity .
c. Check--that the oscilloscope display is 0 volts
t50 mV .
d . Adjust--the Common Mode Bal control for 0 volts
±50 mV .
4 . Input Current Adjust
Calibration-7A19
e. Disconnect all test equipment and reconnect the
signal lines to the plug-in extender . Return the calibration
oscilloscope Vertical Mode to Left .
a. Adjust-the Input Current control for minimum
vertical trace shift (±1 division) while switching the Input
Coupling switch between DC and GND.
b. Return the Input Coupling switch to DC .
5 . Temperature Compensation Adjust
a . Connect a 1 kHz, 0.2 volt square-wave signal from the
oscilloscope Calibrator to the 7A19 INPUT using a 42 inch
BNC cable.
b. Set the 7A19 VOLTS/DIV switch to 50 mV .
c. Connect a shorting strap across the silicon resistor,
R74 (TP73 and TP76 are connected to either side of R74
to provide a convenient means for connecting the shorting
strap) .
d . Adjust--the Temperature Compensation control by
turning clockwise until the waveform just begins to
increase,
e. Remove the shorting strap and return the VOLTS/
DIV switch to 10 mV .
f. Disconnect all test equipment.
N
/6 . GAIN Check/Adjust
a. Connect the Standard Amplitude Calibrator out-
put to the INPUT connector with a 42 inch BNC cable.
b . Set the Standard, Amplitude _Calibrator for a 60,-
millivolt square-wave output and set the Input Coupling
switch to DC .
c. Check--CRT display for a vertical deflection of six
divisions ±0 .18 division .
d. Adjust-Front panel GAIN control for exactly six
divisions vertical deflection .
5-5