(3) TP5282.
(6) Repeat (2) through (5) above to compensate for
(f) TP5190.
interaction of control settings.
(7) Connect output of video signal source (A6)
b. Adjustments
directly to CH-A input of vectorscope (A5).
(1) Adjust C1384 (fig. 5) until 4.1 MHz multiburst
(8) Adjust vectorscope CH-A gain until displayed
packet and white bar are of equal amplitude (R).
burst tip is exactly on graticule edge.
(2) Adjust L1632 and L1628 (fig. 5) for equal
(9) Connect video signal source output to TI
amplitude of burst on both sides of VIR signal phase.
PROGRAM IN, and connect TI PROGRAM OUT to
(3) Perform corresponding adjustments for zero
vectorscope CH-A input.
volt at each test point listed below (see fig. 4).
(10) While rotating R5250 (fig. 4) to display both
(a) TP5382 R5464 (R).
sides of VIR signal, verify that burst amplitude on both
(b) TP5897 R5876 (R).
sides is equal. If amplitudes are unequal, perform b(2)
(c) TP5682 R5470 (R).
below.
(d) TP5687 R5874 (R).
(11) Adjust R5250 to overlay burst and VIR signal
(e) TP5282 R5174 (R).
vectors.
(f) TP5190 R5172 (R).
(12) Remove fuses F5692 and F5691 (fig. 4).
10. Line-Time Non-Linearity. a. Performance Check
(13) Set waveform monitor for differential
(1) Adjust video signal source (A6) for
measurement.
unmodulated, 5-step staircase output.
(14) Adjust R5406 and R5404 (fig. 4) for null on
(2) Adjust A input of waveform monitor (A7) for 1
waveform monitor.
volt full scale.
(15) Set waveform monitor for single channel
(3) Difference in riser amplitude between any two
operation, and adjust R5800 (fig. 4) for flat bottom on
steps will be 3.6 millivolts or less.
12.5 T pulse.
b. Adjustments. No adjustments can be made.
(16) Set waveform monitor for differential
11. Intermodulation and Delay. a. Performance
measurement, and adjust R5308 (fig.
4) for null
Check
indication.
(1) Adjust video signal source (A6) for modulated
(17) Adjust R5208 (fig. 4) to overlay burst and VIR
pedestal output.
signal amplitude as displayed on vectorscope.
(2) Set response switch of waveform monitor
(18) Adjust R5108 (fig. 4) to overlay burst and VIR
(A7) to LOW PASS.
signal phase as displayed on vectorscope.
(3) Change in pedestal level caused by
(19) Set waveform monitor for differential
intermodulation will not exceed 3.7 millivots.
measurement.
(4) Adjust video signal source output for
(20) Adjust R5858 and R5450 (fig. 4) for null
modulated 12.5 T pulse.
indication on waveform monitor.
(5) Verify that chrominance to luminance delay at
(21) Repeat (15) above, but adjust R5854 (fig. 4).
baseline of 12.5 T modulated pulse is 5 nanoseconds or
(22) Repeat (16) above, but adjust R5650 (fig. 4).
less. Any sine wave shape of the chrominance at
(23) Repeat (17) and (18) above, adjusting R5150
baseline will be 7 millivots peak to-peak or less.
and R5250 (fig. 4), respectively.
(6) Adjust PHASE control of vectorscope (A5) to
(24) Replace fuses F5692 and F5691 removed in
set burst vector at 180 graticule line.
(12) above.
(7) Set TI to bypass mode. Burst vector will not
(25) Connect oscilloscope (A4) to test points listed in
shift more than 5 from 180 graticule line.
(a) through (f) below, using probe (B2).
b. Adjustments. No adjustments can be made.
Refer to figure 4 for test point locations. If oscilloscope
does not indicate zero volt dc at each test point, perform
(1) Connect jumper P669 on 0-carrier reference
b(3) below.
board (fig. 6) so that R679 is connected to P679-5.
(a) TP5382.
(b) TP5897.
(c) TP5682.
(d) TP5687.
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