Checks and Adjustments

3.Adjust Geometry, Focus, and Astigmatism

Display the DAC test pattern by completing parts a. through c.

a.Press both the 1705A SPAN/DIV buttons simultaneously to display the Main Menu.

b.Press either SPAN/DIV button to move the cursor to TEST, then press the INPUT button to display the TEST menu.

c.Press either SPAN/DIV button to move the cursor to DAC, then press the INPUT button to display the DAC test pattern.

d.Set the front-panel FOCUS control so that it is approximately at the center of its rotation.

e. ADJUST - R45 (GEOM) for 35V 1V at pin 1 of J3.

f.ADJUST - R11 (CTR FOCUS) and R49 (ASTIG) for the most clearly-defined DAC test pattern. See Figure 5-8.

Tek

+ f

REF

-10

-20

-30

-40

-50

-60

-70

L

O

G

Figure 5-8: DAC check waveforms used to check Focus, Astigmatism, Geometry, and setting of the Trace Rotation (DAC test pattern may vary in size from instru- ment to instrument)

4.Adjust Trace Rotation

a.ADJUST - the front-panel TRACE ROTATION potentiometer for a level display, using a crt graticule line as a reference.

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1705A Spectrum Monitor

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Tektronix 1705A instruction manual Tek