TB 9-4931-501-35
(3) Position time base (A4) controls as listed in (a) through (f) below:
(a) MAIN SEC/DIV switch to 2 s (microsecond).
(b) VARIABLE control to CAL.
(c) AUTO TRIG switch in.
(d) AC COUPL switch in.
(e) POSITION control to center display.
(f) MAIN TRIG LEVEL control for a stable display, triggered on the rising
portion of the pulse.
(4) If pulse displayed does not have a flat top and square leading corner
(aberrations less than 0.36 division), perform b(1) through (4) below.
(5) Set calibration fixture REP RATE switch to 1 MHz.
(6) Set time base MAIN SEC/DIV switch to 0.1 and, adjust MAIN TRIG LEVEL
control for a stable display triggered on rising portion of the pulse.
(7) If pulse displayed on TI does not have a square leading corner and
aberrations are not less than 0.36 division, perform b(5) below.
(8) Press TI POWER switch to off and remove calibration fixture from left and
install in T center vertical compartment. Set time base TRIG SOURCE switch to
I
RIGHT.
(9) Pull TI POWER switch to on and repeat (2) through (7) above. If necessary,
compromise vertical compensation adjustments for TI left and center vertical
compartments.
b. Adjustments
(1) Adjust R121 (fig. 4) for optimum flat top on pulse displayed on TI screen.
(2) Set time base MAIN SEC/DIV switch to 1 s and adjust R120 (fig. 4) for
optimum flat top on displayed pulse.
(3) Set time base MAIN SEC/DIV switch to 0.5 s and adjust R123 (fig. 4) for
optimum flat top on displayed pulse.
(4) Repeat (1) through (3) above as necessary to obtain optimum flat top on
displayed pulse.
(5) Adjust C637 (fig. 1) (main interface board between vertical compartments,
serial number B063251 and up), C115, R115, C155, R155, R167, and C181 (fig. 4) for
optimum pulse display on TI screen.
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