First-Time Operation - Tektronix 3A6 Instruction Manual

SECTION 2
OPERATING INSTRUCTIONS
FUNCTION OF FRONT-PANEL CONTROLS
AND CONNECTORS
The function of all controls and connectors except the
CALIB, MODE, INV (CH 1) NORM and TRIGGER CH 1
ONLY are identical for both channels.
Input Signal input connector.
POSITION
VOLTS/DIV
Controls vertical position of the display.
Selects vertical deflection factor. (VARI-
ABLE control must be in CALIB position for
deflection factor indicated on front panel.)
VARIABLE Provides continuously variable deflection
factor to about 2.5 times setting of VOLTS/
DIV switch.
Light indicates that VARIABLE control is not
set to CALIB.
Screwdriver adjustment to set de balance
of the amplifier.
UNCAL
DC BAL
AC DC GND Selects signal coupling method.
AC: Blocks de component of applied signal.
DC: Directly couples the applied signal to
grid of input stage.
GND: Grounds grid of input stage (does
not ground applied signal).
CALIB Screwdriver adjustment to set the basic
deflection factor of the plug-in unit.
MODE Selects mode of operation.
CH 1: Displays Channel 1 signal only.
CH 2: Displays Channel 2 signal only.
ALTER: Dual-trace display of both Chan-
nel 1 and 2 signals. Display is switched
between channels at end of each sweep.
CHOP: Dual-trace display of both Chan-
nel 1 and 2 signals. Display is switched
between channels at about 150 ke rate.
ADDED: Displays algebraic sum of Chan-
nel 1 and Channel 2 signals.
INV (CH 1)
NORM
TRIGGER CH 1
ONLY PULL
Inverts the Channel 1 display when in the
INV position.
Selects triggering from Channel 1 signal
when pulled out. When pushed in, trigger-
ing signal is obtained from combined
Channel 1 and Channel 2 signal.
FIRST-TIME OPERATION
The following steps are intended to acquaint the operator
with the basic overall operation and function of the Type
@1
3A6. More specific operation and basic application informa-
tion is given later in this section.
1. Insert the Type 3A6 into the left-hand (Y-axis) plug-in
compartment of the indicator unit. Insert a time-base plug-
in unit such as a Tektronix Type 3B] or 3B3 into the right-
hand (X-axis) plug-in compartment (except with Type 565 or
RM565).
2. Set the front-panel controls as follows:
AC DC GND DC (both channels)
VOLTS/DIV 5 (both channels)
VARIABLE CALIB (both channels)
POSITION Midrange (both channels}
MODE CH 1
INV (CH 1) NORM NORM
TRIGGER Pushed in
3. Turn on the indicator unit power. If there is any doubt
as to the operation of the indicator unit or time base, see
the instruction manuals for these units.
4. Set the indicator unit calibrator for 1 volt output and
the time-base for a sweep rate of 5 milliseconds.
5. Connect the calibrator output to both the Channel 1
and Channel 2 input connectors, Adjust the time-base trig-
gering controls for a stable display.
6. Turn the Channel 1 POSITION control to move the dis-
pley above the graticule centerline.
7. Set the MODE switch to CH 2. A two-division display
similar to the previous display should be seen. Turn the
Channel 2 POSITION control to move the display below
the graticule centerline.
8. Set the MODE switch to ALTER; the Channel 1 and 2
displays as set up in steps 6 and 7 should be seen. Turn
the time-base time/division switch to a faster sweep rate.
Notice that the flicker between traces decreases as the
sweep rate is increased. Return the time/division switch to
5 milliseconds.
9. Set the AC DC GND switch to AC. Notice the dif-
ferentiation of the 60-cycle calibrator waveform which
indicates loss of low frequencies due to the coupling capaci-
tor. Return the switch to the DC position.
10. Turn one of the VARIABLE controls throughout its
range. The deflection of that channel should decrease by a
factor of about 2.5 to 1. Return the VARIABLE to CALIB.
11. Set the MODE switch to CHOP; the display should be
identical to ALTER but with less flicker between traces.
Turn the time-base time/division switch to 10 microseconds.
Notice the switching between channels as shown by the
segmented trace. Reduce the sweep rate slowly and notice
that the trace appears solid at about 0.1 milliseconds. This
is the fastest sweep rate at which CHOP mode can be used
and still obtain a satisfactory display.
2-1