TB 9-6625-1982-24
(5) ATTEN pushbutton to X1 (out).
(6) SOURCE pushbutton to EXT (out).
(7) 50
pushbutton to 50
(in).
d. Connect mainframe power module to 115 V ac source, if not previously done.
e. Pull mainframe power module ON-OFF PWR switch to ON and allow at least 30
minutes (60 minutes if in high humidity) for equipment to warm-up and stabilize.
35. 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 TI Oscillator test point TP1436 (fig. 6) using 10 X probe to frequency
difference meter SIG INPUT.
(2) Connect time/frequency workstation 1 MHz OUTPUT to frequency difference
meter REF INPUT.
(3) Verify that the difference indication on the frequency difference meter is within
6 PPM ((OPT 01 and 508A OPT 01) is within 1.2 PPM).
(4) If within tolerance disconnect connections made in a (1) and a (2) above and
proceed to next paragraph. If out of tolerance perform b below.
b. Adjustments
(1) Adjust Standard time base accuracy adjustment C1310 (Option 1 time base
adjustment Y1410) (fig. 6) to obtain minimum difference indication on frequency difference
meter with high resolution.
(2) Allow 24 hours for time base oscillator stabilization. Frequency difference meter
will remain within 1 part in 10-6 (OPT01 and 508A OPT 01) 2 parts in 10-8).
(3) Disconnect connections made in a (1) and a (2) above.
(4) No further adjustments can be made.
