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Performance Verification
1780R-Series Service Manual
4–63
e. Check that the SCH dot is located near the compass rose and that it is
within 5_ of the 180_ axis for NTSC or PAL.
f. Connect the Frame/Black (NTSC) or Frame Ref (PAL) signal from the
television generator to the CH 1 Input to the test scope dual trace
amplifier. Connect the 1780R-Series LINE STROBE OUT to the CH 2
Input of the dual trace amplifier. See Figure 4–12.
Figure 4–12: Connections for checking line strobe pulse timing
NOTE. The television generator is factory set to output a frame pulse on the
Frame/Black or Frame Ref. If the pulse is internally disabled by a jumper
change, restore the jumper to the factory-set position.
g. Trigger the test scope from CH 1 and set the Display Mode to Chop. Set
test scope time base to 10 ms/Div, vertical Volts/Div to 5.
h. Push the 1780R-Series LINE SELECT button. Turn on the touch screen
Line Select menu and select 1–IN–4 (NTSC) or 1–IN–8 (PAL).
i. Rotate the 1780R-Series Precision Measurement knob to display line 7
(NTSC) or line 11 (PAL).
j. Check that the line strobe pulse displayed on the test scope is within 1
division of the strobe output by the television generator.
k. Disconnect the TSG-170A (or TSG-271) signal from the 1780R-Series
instrument. In its place, connect the television test signal generator (1410
or 1411) Color Bar signal to the CH A INPUT connector. Connect a
coaxial cable from the other CH A INPUT connector to the EXT REF
connector. Check that the EXT REF connector is terminated into 75 W.