Filter
Top Products
Performance Verification
4–56
1780R-Series Service Manual
d. Check that the color vector dots are located within 50% of the distance
between the center of the boxes and edges of the boxes.
e. Check that the button under the Vectorscope CRT is On. Press the
CALIBRATE button and select the CAL OSC–ON pad on the Waveform
CRT.
f. Check that the test circles are overlayed within 0.36 mm (typically one
trace width) and located on the compass rose as displayed on the
Vectorscope CRT.
g. Press the CONFIGURE button and select PAGE 2 menu. Select
BARS–100% on the Vectorscope CRT. Press the CONFIGURE button to
exit the menu.
h. Set the generator Color Bar Ampl button to 100%.
i. Check that the color vector dots are located within their boxes.
j. Set the generator Color Bar Ampl button to 75%.
k. Set the 1780R-Series controls as follows: PHASE SHIFT button–Off.
Select CONFIGURE–On, PAGE 2, BARS–75%, and CONFIGURE–
Off.
l. Leave the color Bar signal connected to the CH A INPUT connector.
50. Check Subcarrier Regenerator
Requirement: Pull-In Range: ±50 Hz of F
SC
for NTSC; ±10 Hz of F
SC
for
PAL. Phase Shift with Burst Amplitude Change: ±2_ from nominal burst
amplitude to ±3 dB. Phase Shift with Input Channel Change: ±2_.
a. Check that a Color Bar signal is applied to the CH A INPUT connector
and Black Burst is applied to EXT REF.
b. Set the television test signal generator SPG2, Option AA, Variable
Subcarrier Frequency Offset push-button switch to On. Set the Frequen-
cy button to offset the frequency 50 Hz for NTSC. (For PAL, use the
SPG12, Option AA, button to offset the frequency 10 Hz.)
c. Check that the vector display locks in when the generator Frequency
Offset button is set to + and then to – (minus).
d. Set the generator Subcarrier Frequency Offset buttons to + and Off.
e. Remove the end-line termination from the 1780R-Series EXT REF
connector. Connect a coaxial cable from the EXT REF connector
through a feed-through terminator to Ch 1 input of the test oscilloscope
dual-trace amplifier.