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Section V
5-17
5-22
Paragraphs
to
STD-A-0391
b. Set Model 403A FUNCTION to 15 C P S - 1 MC.
Set RANGE to 1 V.
c. Set test oscillator
j u s t amplitude f o r a 1 V indication on
Model 403A.
d. Increase test oscillator frequency u n t i l Model
403A indication
dropsto0.707V. This should
occur at a frequency of 637 ke or
verifying an input
on the 1 V range.
oscillator
Resettest
e.
Model 403A RANGE to 0 . 1 V. Adjust test
oscillator amplitude f o r a 0 . 1 V indication on
the Model 403A.
Increase test oscillator frequency u n t i l Model
f.
403A indication
dropsto0.707V. T h i s should
occur at a frequency of
verifying aninput capacity of 40pf or
the 0 . 1 V range.
5-17.
NOISE TEST.
5-18.
A shielded 100 kQ load is r e q u i r e d f o r t h i s test.
NOTE
Figure
5-8 l i s t s the
the construction of the 100 kQ shielded
load.
a. Connect a shielded 100 kQ load across the
Model 403A INPUT terminals as shown in
Figure 5-9.
frequency
to100
cps.
Ad‑
the
higher,
capacity of less than 25 pf
frequencyto100cps. Set
398
kc or higher,
less
on
parts and shows
~
o t ,
Connector, male
Connector, m a l e ,
sulator
90°
L u g , t e r m i n a l
100
R e s i s t o r,
K ohms,
1/2
1%,
W
i n t . lock
Wa s h e r,
6-32
Spacer,
threaded
Shield
S c r e w, b i n d . head,
x 1/4
i n .
5-9. Noise
Figure
b. Set FUNCTION to 15 C P S - 1
0.001
After the i n i t i a l
t o
V.
Model 403A should indicate between 0 and 6%
of f u l l scale. This verifies noise lessthan
6% of f u l l scale on the 0.001 V range.
c. Switch RANGE to
dicate between 0 and 3% of f u l l scale.
d.
c f o r the 0.01 to 300 V ranges.
Repeat step
On each range the meter should indicate be‑
tween 0
and 3%of f u l l
of less than 3% of f u l l scale on a l l ranges
0.001
above
V.
5-19.
A D J U S T M E N T A N D C A L I B R AT I O N .
5-20. The
following paragraphs contain a complete
adjustment and calibration procedure f o r the Model
403A.
Figures 5 - 1 and
5-2 show the location of the
internal
adjustments. F o r best accuracy,
justments
should be performed in the order
5-21. METER MECHANICAL
5-22.
meter mechanical zero
The
when the instrument is at normal operating tempera‑
in i t s n o r m a l operating position, and turned
t u r e ,
M o d e l 403A
1251-0174
w/in-
1251-0175
|
0360-0042
0757-0839
=
2190-0007
0380-0058
1251-0173
6-32 | 2470-0001
Te s t
MC; set RANGE
the
t r a n s i e n t ,
0.003
V.
M e t e r shouldin‑
verifying noise
s c a l e ,
the a d ‑
given.
ADJUSTMENT.
ZERO
should be checked
00125-4
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