Advertisement
Model 3455A
Section VIII
SERVICE
GROUP
B
8
B-1.
AUTO-CAL
AND
DC TROUBLESHOOTING
(INGUARD).
8-B-2. All
3455A
input
signals travel
through
the
main
dc ampliner
and Auto-Cal
circuits.
In
order
to
troubleshoot
D.C. and Auto-Cal
malfunctions, a
good
fundamental knowledge of
the
3455A's
Auto-Cal and
self-test
routines are required.
B-B-3.
Auto-Cal Constants.
8-B-4.
There
are
14
cal
constants used
in
the
34SSA, which
are usually zero
and
full
scale
voltage
"readings".
These
account
for
most
offsets,
gain,
and
drift
of
the input
op-amps.
The
"readings"
are
taken
periodically
when
the
3455A
is
in
the
Auto-Cal
mode.
A
condensed
description
of
all
the
cal
constants
are
in
Table
8-B-I.
If
a
more
detailed description
of
the
cal
constants
is
desired, refer to the
appropriate
paragraph
in
the
Theory
of Operation
section
of
this
manual.
Table
8-B-I.
Aute-Cal Constants
Coutul
N'aoibtr
CoBsiani Oncriplioo
Circa
its
Used
Detailed
Ooe
ration
13
lo.
no
Inout
-
A/D
oHsei
measurement
Fsrsoraoh
8-4S
12
l±.lratio-± 10
V
reference
input,
A/D
current
ration
measurement.
—
Paragraph
8-46
1
1
10
V
offset
-
XI
gain
with
amplifier
input
tied
to grourtd. Input
attenuator
at
XI
asm.
Figure 8-B-I
Paragraph
8-24
10
10
V
jain
-
XI
gain with
amplifier tied to
10
V
reference. Input attenuator
at
XI
gain.
Figure
6-8-2
Paragraph 8-27.
9
Ohms
and
.5
V
offsets
-
X20
gain with
amplllier
input
tied
to grourtd. Input
anen-
tuator at
XI
gain.
Figure
8-B-3
Paragraph
8-39
8
Ohms
and 5
V
offsets
—
X2
gain with
amplifier
input
tied
to
ground.
Input
et-
tenuator
of
XI
gain.
Figure
8-B-4
Paragraph
8-39
7
100
V
offset
#2
(XI)
-
gain
with
amplifier
input
tied
to
10:1 attenuator with top
of
10:1 attenuator
tied
to
ground.
Figure
8-B-5
Paragraph
8-26
6
1000 V
Offset
-
X1
gain
with
amplifier
tied
to
100:1
attenuator with top
of
100:1
attenuator
tied to
ground.
Figure
B-B-6
Paragraph
8-26
5
1
00 V
gain
•
X
1
0
gain with
amplifier
tied
to
10:1 attenuator with top
of
10:1
at-
tenuator
tied
to
X10 V
reference.
Figure
B-B-7
Paragraph 8-31
4
100
V
offset
ei 1X10)
•
X10
gain
with
amplifier
input
tied
to
10:1
attenuator
with
top
of
10:1
attenuator
tied
to
ground.
Figure
8-B-8
Paragraph
8-33
3
.1
V
offset
-X100
gain with
amplifier
in-
put
tied
to
ground.
Input
attenuator
of
X
1
gain.
Figure
8
B
9
Paragraph 8
26
2
1
Voffsetfl -X10
gain with
amplifier
in-
put
tied
to
ground.
Input attenuator
of
XI
gam.
Figure
8-B-IO
Paragraph
8-25
1
1
V
offset
«2
-X
10
gain
with
amplifier
in-
put
tied
to
10:1
divider.
Top
of divider
shorted
to
ground.
Input attenuator
at
XI
gam.
Figure 8-B-1
1
Paragraph
8-30
0
1
V
gain
-X10
gain
with
amplifier tied to
10:1
divider
with
10
V
at the
top
of the
divirfer.
Inout attenuator
at
X
gain.
Figure 8-B-I
2
Paragraph
8-28
8-43
Advertisement
