53 Performance Check

5-4. CRT CONTROLS.

a. Install a single large plug-in or two small plugin units in the Model 140A (vertical plug-in in the lower compartment, horizontal in the upper compartment) .

AMPLIFIER coupling (if present) . AC POSITION controls Centered c. If a time base plug-in is being used, set: SWEEP TIME 1 MSEC/CM

TRIGGER SOURCE +INT

LEVEL FREE RUN

NORMAL/SINGLE NORMAL

d. A trace should be on screen. If necessary, turn INTENSITY control clockwise.

e. Remove trace from screen with POSITION controls. Depress BEAM FINDER. The trace should appear on screen.

f. The INTENSITY control should vary the intensity of the display from extinguished to brighter than normal intensity.

g. The FOCUS and ASTIGMATISM controls should defocus the display at the extreme of each control, and focus the display at approximately midrange. Adjust FOCUS and ASTIGMATISM for sharpest overall display.

h. Adjust TRACE ALIGN to set the trace parallel to the horizontal graticule lines. If the horizontal plug-in is not a time base, connect the calibrator signal to the horizontal amplifier input to produce a straight-line trace.

5-5. CALIBRATOR.

a. Set: Vertical SENSITIVITY 0.05 V/CM

INPUT coupling DC

b. Connect 1 VOLT PTP from the Voltmeter Calibrator to vertical INPUT.

c. Adjust vertical VERNIER for exactly 10 cm deflection.

d. Disconnect the Voltmeter Calibrator and connect the IV CALIBRATOR output to the vertical INPUT.

f. Repeat steps a through e, using 0.5 V/CM vertical SENSITIVITY and 10 volts from the Voltmeter Calibrator.

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