Performance Check/Calibration—Type 422 AC-DC
Fig. 5-12. (A) Location of step attenuator balance adjustment (front
panel), (B) location of variable balance adjustment (Channel 1 and
Channel 2 Input Amplifier boards).
g. CHECK—Deviation from straight line should not
exceed ±0.1 division.
h. Position the trace to the bottom horizontal line of the
graticule.
i. CHECK—Deviation from straight line should not
exceed ±0.1 division.
j. Return the VARIABLE TIM E/DIV control to CAL.
13. Check/Adjust Channel 1 Step Attenuator and
Variable Balance
a. Set both Input Coupling switches to GND.
b. Position the trace to the center horizontal line with
the Channel 1 POSITION control.
c. CHECK—Change the Channel 1 VOLTS/DIV switch
from .05 to .01. Trace should not move more than 0.1
division vertically.
PERFORMANCE CHECK ONLY
Front-panel adjustment; can be adjusted as part of
performance check.
d. ADJUST—Channel 1 STEP ATT BAL adjustment
R21 (see Fig. 5-12A) for minimum trace shift as the
Channel 1 VOLTS/DIV switch is changed from .05 to .01.
e. Set the Channel 1 VOLTS/DIV switch to .05.
f. CHECK—Rotate the Channel 1 VARIABLE
VOLTS/DIV control throughout its range. Trace should not
move more than 0.2 division vertically.
NOTE
This tolerance is provided as a guide to correct
instrument operation and is not an instrument
specification.
g. ADJUST—Channel 1 Var Bal adjustment R35 (see
Fig. 5-12B) for minimum trace shift as the Channel 1
VARIABLE VOLTS/DIV control is rotated throughout its
range.
Fig. 5-13. (A) Common-mode current test point and adjustment (Vertical Switching and Output Amplifier board), (B) typical test
oscilloscope display showing test limits (vertical deflection, 0.2 volt/division, sweep rate five milliseconds/division).
5-16
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