Tektronix 221 Instruction Manual page 9

Functions of Controls And Connectors—221 Service
VOLTS/DIV
SWP CAL— screwdriver adjustment to set the basic
tim ing of the horizontal system.
TRACE ROTATION— screwdriver adjustment to align
trace w ith graticule lines.
EXT TRIG OR HORIZ INPUT— banana jack for input of
an external trigger signal or for input of an external
horizontal (X) signal for X-Y operation.
LEVEL/SLOPE— selects the amplitude point and slope
of the trigger signal on which the sweep is triggered. When
the indicator dot is to the left of center, the sweep is
triggered on the positive-going slope of the trigger signal; to
the right of center, on the negative-going slope. When the
LEVEL/SLOPE control is set to the AUTO PRESET
detent, the sweep is automatically triggered at a preset level
on the positive-going slope.
AUTO PRESET— screwdriver adjustment to set the
PRESET trigger point fo r AUTO sweep operation.
2-2
Fig. 2-2. Side panel showing controls and connectors.
turns OFF instrument power).
display
relative charge level o f the internal batteries.
control). Controls power to the instrument. Does not
interrupt charging current to the internal batteries when
connected to an AC line voltage.
between the 221
equipment under test.
EXT-INT— selects the source of the trigger signal.
INTENSITY— controls brightness of crt display (detent
FOCUS— screwdriver adjustment to obtain a well-defined
BATTERY— expanded scale
POWER—(counterclockwise detent of the INTENSITY
COMMON—banana jack to establish common ground
and the external
meter to indicate the
signal source or
REV. B, FEB. 1977