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Performance Verification
4–14
1780R-Series Service Manual
i. Check that the CAL readout on the Waveform CRT is 1000 mV ±2 mV.
j. Set the WAVEFORM GAIN–VAR–X5 to Off. Set the INPUT to CH A.
Leave the RIGHT DISPLAY set to WFM+CAL, the CONFIGURE
button set to On, and the VAR/FIX selection set to VAR on the
Waveform CRT menu when starting the next step.
k. Disconnect the VAC signal from the instrument.
4. Check Volts Full Scale Accuracy
Requirement: Volts Full Scale Accuracy: 1.0 V ±0.007 V.
a. Check that no signal is applied to the CH A INPUT connector.
b. Check that the CONFIGURE button is set to On. Select COUPLING–
GND on Page 1 of the menu. Check that the button below the Waveform
CRT is On, the RIGHT DISPLAY is set to WFM+CAL, and VAR/FIX
(on the Waveform CRT menu) is set to VAR. Check that ABS is selected
on the Waveform CRT menu.
c. Use the Precision Measurement control to obtain a 1 volt amplitude
display. Use the VERT POS control and appropriate graticule lines as
aids while obtaining the correct display height.
d. Check that the CAL readout is 1000 mV ±7 mV on the Waveform CRT.
e. Turn the Precision Measurement control to obtain a 200 mV CAL
readout.
f. Set the WAVEFORM GAIN to X5.
g. Rotate the VERT POS and Precision Measurement controls so the
display height appears to be 1 volt full scale (actually 200 mV) using the
appropriate graticule lines.
h. Check that the CAL readout is 200 mV ±7 mV.
i. Set the WAVEFORM GAIN–X5 to Off. Turn the Precision Measurement
control so the CAL readout is 1000 mV. Select COUPLING–DC on the
Configure menu.
j. Select FIX on the Waveform CRT menu and set the RIGHT DISPLAY
to WFM.
5. Check Variable Volts Full Scale Range
Supplemental: Variable Volts Full Scale Range: 0.5:1 to 1.5:1 (0.67 V to
2.0 V input signal can be made full scale).
a. Apply a modulated Pulse & Bar signal, through a 75 W feed-through
terminator, to the 1780R-Series CH A INPUT connector.