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Adjustment Procedures
5–58
1780R-Series Service Manual
h. Disconnect the Pulse & Bar signal from the front-panel PROBE input
connector.
47. Adjust Probe Frequency Response
a. Connect the television test signal generator Multiburst signal, through a
75 W feed-through terminator, to the 1780R-Series front-panel PROBE
input connector.
b. Connect a 75 W end-line termination to the rear-panel PIX MON OUT
connector.
c. Select PROBE-X1 on PAGE 2 of the Configure menu. Check that DC
RESTORER-OFF is selected on PAGE 1. Select RIGHT DISPLAY-
WFM mode. Check that INPUT-PROBE and WFM HORIZONTAL-
ONE-FIELD are selected on the front panel.
d. Set the generator multiburst controls to obtain a Full Amplitude,
Composite, High Frequency Range Sweep with markers output signal.
e. Adjust Probe Resp (A2C1222) for flat frequency response, within ±3%,
to 10 MHz.
f. Attenuate the Multiburst signal by inserting a 75 W 10X attenuator
between the coaxial cable from the signal generator and the 75 W
feed-through terminator.
g. Check that the CONFIGURE button is On. Select PROBE-X10 on
PAGE 2.
h. Adjust Probe X10 Resp (A6C394) for flat frequency response, within
±3%, to 10 MHz.
i. Disconnect the Multiburst signal from the PROBE input connector.
j. Connect the output of a leveled sine wave generator through a
50 W-to-75 W minimum loss attenuator, a 75 W 10X attenuator, and
75 W feed-through terminator to the 1780R-Series front-panel PROBE
input connector.
k. Select WFM HORIZONTAL-TWO-LINE mode.
l. Set the leveled sine wave generator output frequency to 50 kHz and the
output amplitude to display a 100 IRE (700 mV for PAL) peak-to-peak
signal on the 1780R-Series Waveform CRT. This is the reference
amplitude.
m. Set the generator output frequency to 1 MHz.
n. CHECK that the displayed amplitude on the Waveform CRT is within
±3% or ±21.4 mV for NTSC (±21.0 mV for PAL) of the amplitude noted
in part l. of this step.