Focus
Set the SEC/DIV switch to X-Y and the INPUT COUPLING
switch's to GND. With no signal applied, adjust the FOCUS for
optimum focus of the CRT display (a single dot).
Auto Preset
Connect the CH 1 probe tip to a sine-wave signal source within
the bandwidth limits of the 212. Set the LEVEL/SLOPE control to
the AUTO PRESET detent and adjust the VOLTS/DIV and SEC/DIV
switches for a display approximately four divisions in amplitude with
one cycle of signal displayed every two or three divisions. Vertically
center the display about the center horizontal graticule line using the
CH 1 POS control. Adjust the AUTO PRESET adjustment so the
CRT display starts on the center horizontal graticule line.
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212 Operators Handbook