Table of Contents
Advertisement
т
+
5-31,
а,
ж ям
A2C3
IOM
IMC
L
Model 427A
A2Ri7
A2R5
JOMV
4ООСР5 ADJ
*
0000000000
OOCOCGOGGOO
SgTA-C-OTM
LEFT SIDE
A2R3
lV
ОС CAL
Figure 5-6.
NOTE
Before beginning the
calibration,
be
sure to adjust the mechanical
meter
zero according to the steps in Para-
graph 3-6.
AMPLIFIER BALANCE
AND ZERO OFFSET
JUSIMENT.
Short VOLTSand COM terminals; set FUNC-
TION to either +DCV or -DCV.
Set DC ZERO/Q= for zero deflection.
Remove
shorting connection from VOLTS and
COM terminals.
If meter deflects,
adjust
A2R7
OFF
ADJ for zero deflection.
Short
VOLTS
and COM terminals
and recheck zero
adjustment.
Repeat steps b and c if песеввагу.
Turn FUNCTION
to -DCV
and
rotate
DC
ФЕНО/ о fully to the left.
Note meter
indication,
Repeat
steps d and e and adjust A1R15 АМР
BAL
until the meter indication in both steps
is the same,
NOTE
H the range of adjustment A1R15 is
insufficient,
refer to Paragraph 5-74.
REGULATOR
ADJUST.
Complete Amplifier Balance and Offset adjust-
ment (Paragraph 5-30).
01791-2
A2R4
М
. 5
ОС CAL
Section У
AIRIS
XIO
OHMS CAL
AIR2O
XIK
OHMS
CAL
AIR (5
AIRS
AMP BAL
REG ADJ
ӘАОО
О
mem
О СО
RIGHT SIDE
3V
ЮОКС
ADJ
Location of Internal Adjustments
b.
Short VOLTS to СОМ and OHMS to COM.
Set
FUNCTION
to +DCV.
Meter
should be zero-
ed within 2 minor divisions upscale.
5-32.
AC CALIBRATION.
5-33.
Three adjustments must be made to calibrate
the ac circuits in the Model 427A.
First,
A2R17
ad-
justs the absolute
amplitude calibration with a 10 ту
400 Hz input.
Then A2C3 is adjusted with a 10 mV 1
MHz
input to calibrate
the
high frequency
response.
Finally
the frequency response
of the AC Range At-
tenuator is set by adjusting C3 with a 3
100 kHz
signal applied to the input.
5-34.
LOW FREQUENCY
CALIBRATION.
а.
Connect the Model 427A as shown
in Figure
5-1, and set 51 to position A.
b.
Set the voltmeter
calibrator
output to 400 Hz
at 0.01 volt rms,
and set the 427A RANGE
to 0.01 and FUNCTION to АСУ,
Adjust A2R17 400 CPS ADJ for exactly 0.01
volt indication on the 427A.
If the range of
adjustment A2R17
is insufficient,
refer to
Paragraph 5-81.
HIGH FREQUENCY
CALIBRATION.
Connect the Model 427A аз shown in Figure 5-1.
5-5
Advertisement
Table of Contents
