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IV~H,N I LNANCE
INSTRUCTION
MANUAL
Digital Mullimeler
Models 172. 173
b.
Power
Supply
Check.
The
following
measurements
can
be made using
the
instrument
in
Llt3E or
BAT modes
(if
the
Model
1728
is
installed).
1.
Set
the
internal
Line
Switch
5601
appropriately
for
the
line
voltage
being
used.
2.
Using
DMM ( H ) measure
the
voltages
listed
in
Table
6-10.
TABLE
6-10.
5V to +5.25V
+14.5
to +15.5
NOTE
To achieve
calibration
to published
specifications
the
instrument
should
be cali-
brated
using
the
Model
1725
Calibration
Cover.
The
instrument
should
be allowed
to
stabilize
for
approximately
1
hour
after
the
Calibration
Cover
is
put
in place.
It
is
important
that
the
calibration
sequence
be followed
exactly,
because
the
ad-
justments
are
interrelated
and dependent
on prior
calibration
steps.
c.
A/D
Calibration.
NOTE
This
procedure
must
precede
the
regular
analog
section
calibration
to ensure
that
the
instrument
will
meet
all
rated
specifications.
1.
Capture
Range
Adjustments.
a)
Set
the
DMM to
MAN.
b)
Set
to
300mV DC.
c)
Place
a short
between
input
HI and
LO.
d)
Connect
a Berg-type
Z-pin
housing
(Keithley
~~-266)
with
approx.
30 inch
leads
at
TPlOl
and TPl02
on PC-407
(See
Figure
38).
4
Connect
Oscilloscope
(G)
between
the
following
points.
I.
Oscilloscope
Ext.
TRIGGER
to TPlOl
(FON).
2.
Oscilloscope
VERTICAL
INPUT to
TPIOZ
(Prefilter).
3.
Oscilloscope
GND to
signal
ground
test
point
~1001~
(lo,.,).
f)
Set
the
Oscilloscope
controls
as follows:
1.
Trigger:
+,
DC coupled.
2.
Vertical
:
DC, 0.5
V/division
3.
Time
Base:
20 ms/division
9)
For
the
following
adjustments
refer
to
trace
shown
in
Figure
39.
h)
Adjust
potentimeter
RI03
(AUTO CAL ACAL)
for
a level
of
+lV
+O.ZV
during
AUTO CAL time
period.
AB
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