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Adjustment Procedures
5–16
1780R-Series Service Manual
<HORIZ POS POT>
Select <CONTINUOUS>. This indicates that the instrument has a
continuous Horizontal Position control (dual wiper potentiometer).
<TC ON VC IN LS>
Select <ENABLE>. Timing cursor dots are placed on the Voltage
Cursors when in Line Select for ease in viewing. Voltage Cursors are
automatically enabled when entering Line Select.
4. Adjust Waveform CRT Intensity
a. Set the 1780R-Series INPUT selection to CH B1 for no signal input.
Select WFM HORIZONTAL-TWO-LINE mode. Check that the button
below the Waveform CRT is On.
b. Set the trace to the center of the right CRT using the 1780R-Series
VERT POS control.
c. Rotate the SCALE and INTENSITY controls fully counterclockwise
(“beep” sound).
d. Adjust CRT Bias (A16R420) until the waveform trace just disappears.
(A16 is the Waveform High Voltage supply circuit board. See Fig-
ure 5–7.)
e. Set the front-panel SCALE and INTENSITY controls for normal
intensity.
5. Adjust Waveform CRT Internal Astigmatism and Focus
a. Set the 1780R-Series INPUT selection to CH A. Check that the button
below the Waveform CRT is On.
b. Set the 1780R-Series front-panel FOCUS control to midrange between
“beeps.”
c. Adjust Focus (A16R130) and Astigmatism (A16R122) for well-defined
color bar display.
6. Adjust Vector Intensity
a. Press the button below the Vectorscope CRT.
b. Rotate the 1780R-Series SCALE and INTENSITY controls fully
counterclockwise (“beep” sound).
c. Adjust CRT Bias (A3R373) until the vector dot just disappears. (A3 is
the Vectorscope High Voltage Supply board. See Figure 5–8.)