Front-Panel Controls, Connectors, And Indicators; Main Triggering Controls - Tektronix 7B92A Maintenance Manual

Operating Instructions-7B92A
and the 7B92A in the B horizontal
compartment, the sweep locks up if
the 7B92A is in its Alternate mode
and the Mainframe Horizontal mode
is Alt. Lock-up can be avoided by
changing the Mainframe Horizontal
mode to Chop or B. This allows both
7B92A sweeps to be displayed.
To install the 7B92A in a plug-in compartment,
push it in until it fits firmly into the compartment. The
front panel of the 7B92A should be flush with the front
panel of the oscilloscope. Even though the gain of the
oscilloscope is standardized, the sweep calibration of the
7B92A should be checked when installed.
procedure for checking the unit is given under Sweep
Calibration in the Operating Checkout procedure In this
section.
To remove the 7B92A, pull the release latch (see
Fig. 1-2) to disengage the unit from the oscilloscope, and
pull it out of the plug-in compartment.
Fig. 1-2. Location of release latch.
FRONT-PANEL CONTROLS,
CONNECTORS, AND INDICATORS
All controls, connectors, and indicators required
for the operation of the 7B92A, except the Time/Div
Variable and Mainframe Selectors, are located on the
front panel. A brief description of the front-panel
controls, connectors, and indicators is given here. More
detailed information is given under General Operating
Information. Fig. 1-1shows the Time/Div Variable and
Mainframe Selectors.
controls, connectors, and indicators.

MAIN TRIGGERING Controls

(1) LEVEL Control
Selects amplitude point on trigger signal where sweep
triggering occurs when the MAIN TRIGGERING MODE
AUTO, NORM, or SINGLE SWEEP switches are
pressed. When the MAIN TRIGGERING MODE HF
SYNC switch is pressed, the LEVEL control adjusts the
frequency of the trigger generator to synchronize with the
The
frequency (or sub-harmonic) of the triggering signal to
provide a stable display.
(2) SLOPE Control
Permits triggering on the positive or negative slope of the
trigger signal (except in HF SYNC).
(3) TRIG'D Indicator
When lit, indicates that the sweep is triggered and will
produce a display with correct setting of the POSITION
control and the controls on the associated amplifier plug-
in unit(s) and oscilloscope.
(4) MODE Switches
Select the desired MAIN TRIGGERING mode. Selected
mode is indicated by lighted pushbutton.
AUTO: Selects a triggered sweep initiated by the applied
trigger signal at a point determined by the LEVEL control
and SLOPE control when the trigger signal repetition rate
is above 30 hertz and within the frequency range
selected by the COUPLING switches. When the LEVEL
control is outside the amplitude range, the trigger
repetition rate is outside the frequency range selected by
the COUPLING switches, or the trigger signal is
inadequate, the sweep free-runs to provide a reference
trace.
HF SYNC:
repetition rates above 100 megahertz and within the
range selected by the COUPLING switch. Stable display
can be obtained when the LEVEL control adjusts the
frequency of the trigger generator to the frequency (or
sub-harmonic) of the trigger signal. When the LEVEL
control is adjusted to frequencies between sub-
harmonics, the sweep free-runs.
1-2
Fig. 1-3 shows the front-panel
Sweep initiated by trigger signals with
REV B, JUN 1978