TB 9-6625-1982-24
19. Equipment Setup
WARNING
HIGH VOLTAGE is used or exposed during the performance of
this calibration.
DEATH ON CONTACT may result if
personnel fail to observe safety precautions.
REDUCE
OUTPUT(S) to minimum after each step within the
performance checks where applicable.
CAUTION
To avoid damage to the plug-in circuitry, power must be OFF
on the mainframe power module before connecting the TI.
a. Position TI controls as listed in (1) through (3) below.
(1) FUNCTION switch to PERIOD B and AVGS switch to 10-6 (option 1 to 10-7).
(2) CH A and CH B LEVEL controls to midrange.
(3) CH A and CH B COUPL pushbuttons to AC (in), all others (out).
(4) Display time CCW with pushbutton (out).
b. With power OFF, connect TI to mainframe power module using extender.
c. Pull mainframe power module ON-OFF PWR switch to ON and allow at least 30
minutes (60 minutes if stored in high humidity environment) for equipment to warm-up
and stabilize.
d. Remove left or right side covers of TI as necessary to make connections or
adjustments. Replace cover(s) after completing adjustments.
20. Time Base
NOTE
Adjustment of the Time Base Oscillator is no longer performed
unless an out of tolerance value is determined while
performing the Time Base Performance Check.
a. Performance Check
(1) Connect time/frequency workstation 1 MHz OUTPUT to TI CH B INPUT,
using cable and termination if needed.
(2) Adjust CH B LEVEL control for stable readout on TI display.
(3) Verify that the TI DC503A readout is within 6.0 PPM (DC503A option 1 reading
is within 1.2 PPM with display OVERFLOW light on).
(4) If within tolerance disconnect connection made in a (1) and proceed to next
paragraph. If out of tolerance perform b below.