Filter
Top Products
Adjustment Procedures
5–20
1780R-Series Service Manual
q. Select RIGHT DISPLAY-WFM mode. Press the CONFIGURE button to
On and select COUPLING-DC on PAGE 1. Press the CONFIGURE
button to exit the menu.
r. Disconnect the DMM test leads from A2U810.
NOTE. Leave the 1780R-Series INPUT selection set to CH B1 so that no input
signal is displayed when performing Steps 8 through 11.
9. Adjust Waveform CRT Trace Rotation, Orthogonality, and Geometry
a. Push the 1780R-Series CALIBRATE button.
b. Check that the button under the Waveform CRT is On.
c. Touch the TRACE ROTATION pad on the left hand (Vectorscope) CRT.
Be sure that the circle surrounds the words TRACE ROTATION.
d. Adjust the Precision Measurement control to align the horizontal lines of
the electronic graticule with the Waveform CRT graticule.
e. Adjust WFM Orthogonality (A2R536) so that the vertical lines of the
electronic graticule are perpendicular to the Waveform CRT graticule
horizontal lines.
f. Adjust WFM Geometry (A16R112) for straight electronic graticule lines
on the Waveform CRT. See Figure 5–7.
10. Align Waveform Electronic Graticule
a. Check that the button below the Waveform CRT is On. Check that the
CALIBRATE button is On and TRACE ROTATION is selected on the
Vectorscope CRT.
b. Adjust Vertical Readout Pos (A2R309) and Vertical Readout Size
(A2R215) so that the bottom and top horizontal electronic graticule lines
are aligned with the –40 and 100 IRE graticule lines (0 and 1.0 volt lines
for PAL), respectively. Align the + marks of the Waveform CRT
electronic graticule with the 0 IRE (0.3 for PAL) graticule baseline.
Readjust, as necessary, to obtain the correct alignment.
c. Adjust WFM Readout H Center (A2R170) and WFM Readout H Gain
(A2R167) so the left-hand + mark of the electronic graticule aligns with
the first major division mark on the graticule baseline. Align the
right-hand + mark of the electronic graticule with the 11th major
division graticule mark on the baseline. (Figure 4–7 in Performance
Verification identifies the major division marks on the Waveform CRT
graticule baseline.)