TM 11-6625-3025-14/ET426-AA-MMA-010/E154 VII210/T.O. 33A1-8-902-1-1
5. Sync the oscilloscope from the leading edge (-) of V drive. Observe the V drive waveform and check polarity,
level and width (nominally 667 usec). The pulses should be spaced 16, 667 usec apart, occurring at a 60 Hz rep rate. For
60 Hz field rates, switch oscilloscope sync to line; the pattern should either be stationary or drift very slowly to the right or
left. A rapid travel or apparently out of sync signal indicates that the vertical rate is incorrect, due to improper master
oscillator frequency or improper line count.
6. Observe the blanking output and check level, polarity and width of the V blanking interval (20 lines, 988 usec
at 675 line rate). The H blanking pulses (as adjusted in step 4) should be present at all times except during the V blanking
interval. The upper and lower baselines should be uniform with no tilt, sag or modulation.
7. Sync oscilloscope to the leading edge (-) of V drive. Set oscilloscope sweep at 50 usec/div. Observe the
sync output and inspect for proper waveform. The sync waveform is presented in the industrial format (figure 4-4) by the
selection of jumpers 4 and 6, on the sync card (figure FO-4).
NOTE
If the sync waveform does not appear to be as expected, be sure to check which
jumpers are installed on the sync card.
8. Continue to observe the sync output. Sync oscilloscope from the leading edge (-) of H drive, sweeping scope
at a convenient rate to show the H sync pulses.
9. Adjust the front porch (leading edge delay) to 1 usec by u3e of control (R6) at the edge of the sync card
10. Adjust the output amplitude (R25) of the output pulses on the pulse output card (figure 6-6) for a nominal
level of 4v peak.
6-37.
Test Pattern Section Adjustment Procedure.
a.
Measurement Conditions.
(1) This procedure is based on the 675/60 scan rate, using pulse widths conforming to EIA Standards as
shown in table 6-3.
There is no standard or even common prevailing practice which governs the test requirements or test pattern
content for non-broadcast television systems. The adjustment of pattern content is, therefore, somewhat arbitrary and
may be set according to system specification requirements or prevailing common practice. In the absence of system
standards to the contrary, it is suggested that:
6-25
