Performance Check/Calibration—Type 422 AC-DC
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(A)
Expansion
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IB)
(C) Compression
Fig. 5-16. Typical CRT display showing acceptable compression and
expansion. (A) Expansion, (B) correct deflection at center of
graticule, (C) expansion.
e. CHECK—Compression or expansion not to exceed
0.15 division (see Fig. 5-16).
f. Position the bottom of the display to the bottom
horizontal line of the graticule.
g. CHECK—Compression or expansion not to exceed
0.15 division (see Fig. 5-16).
h. Set the vertical Mode switch to CH 2.
i. Position the display to the center of the graticule with
the Channel 2 POSITION control.
j. Set the Channel 2 VARIABLE VOLTS/DIV control
for exactly two divisions of deflection (see Fig. 5-16B).
k. Position the top of the display to the top horizontal
line of the graticule.
l. CHECK—Compression or expansion not to exceed
0.15 division (see Fig. 5-16).
m. Position the bottom of the display to the bottom
horizontal line of the graticule.
n. CHECK—Compression or expansion not to exceed
0.15 division (see Fig. 5-16).
22. Check Channel 1 and 2 Input Coupling Switch
Operation
a. Return both VARIABLE VOLTS/DIV controls to
CAL.
b. Position display with the Channel 2 POSITION
control so the bottom of the square wave is at the center
horizontal line.
c. Set the Channel 2 Input Coupling switch to AC.
d<. CHECK—CRT display centered about center horizon
tal line.
e. Set the Channel 2 Input Coupling switch to GND.
f. CHECK—CRT display for a straight line near the cen
ter horizontal line.
g. Set the vertical Mode switch to CH 1.
h. Position display with the Channel 1 POSITION con
trol so the bottom of the square wave is at the center
horizontal line.
i. Set the Channel 1 Input Coupling switch to AC.
j. CHECK—CRT display centered about center horizon
tal line.
k. Set the Channel 1 Input Coupling switch to GND.
l. CHECK—CRT display for a straight line near the
center horizontal line.
m. Disconnect all test equipment.
23. Check Trace Shift Due to Input Current
a. Set both VOLTS/DIV switches to .01.
b. Position the trace to the center horizontal line with
the Channel 1 POSITION control.
5-20
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