HP 8340b - Page 471

HOW
TO
RESTORE
FACTORY-OPTIMIZED
CALIBRATION
CONSTANTS
A
printed
copy
of
protected
data
is
included
with
each
instrument.
It
is
stored
in a
bracket
located
under
the
top
cover,
on
the
left
side of the
instrument
(as
viewed from
the
front).
If
working
and
protected
data
in RAM
are
lost,
use
the
information
on
this
sheet
to
restore
the
cal
constants.
When the
instrument
is
recalibrated,
the
printed
copy
protected data
should
be
updated
and placed
back
in
the
instrument
(remember
to
update
protected
data
after
recalibration).
Figure
A-3 shows
an
example
of
a
calibration
constant
printed
copy.
1. Remove
the
top
cover
of
the
instrument.
Inside the
instrument,
find
the
printed
copy
of calibration
constants
(they
are
in a
metal bracket on
the left
side of
the
instrument, as
viewed
from
the
front).
2.
Replace
the
top
cover.
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CCAUTIONJ
This
procedure
affects
data
required
for
optimum
instrument perfor¬
mance.
Be careful
when accessing or
changing
calibration
data.
3.
To
access
the
calibration
constants,
press:
[SHIFT]
[GHz]
[1]
[Hz]
[SHIFT]
[MHz]
[1]
[2]
[Hz]
[SHIFT]
[KHz]
[2]
[2]
[Hz]
The
value
of calibration
constant
#1
is
displayed
in
the
ENTRY
display.
4.
Compare
the
value
on
the ENTRY
display
with
the
value
listed
in
the
print-out.
If
the
values
do not
match:
a.
Enter
the
value from
the
print-out
via
the
DATA ENTRY
keyboard.
b.
Press
[Hz].
5.
To
see
the
next
calibration
constant,
press
the
up
STEP
key.
6.
Repeat
steps
4
and
5
until
all
calibration
constants
are
the
same as
those shown
on
the
print-out.
7.
To
store
the
entered
calibration
constants
into
protected
memory,
press:
[SHIFT]
[MHz]
[1] [4]
[Hz]
[SHIFT]
[KHz]
[5] [3] [4] [9]
[Hz]
CALIBRATION STORED
appears
in
the
ENTRY
display.
8.
Press
[INSTR
PRESET].
The
FAULT
indicator
should
be
off.
If
it
is
still
on,
suspect
a
problem
with
the
instrument's
mem¬
ory.
9.
Replace
the
print-out
inside the
instrument.
HP
8340B/41B
Assembly-Level
Service
Calibration
Constants A-23