LeCroy 9450 - Page 29

Check:
-
There
should
be no large
over-shoot
at
the
rising
and
falling
edge:
50 2:
less than
10
%
overshoot
-
Check
the same
at 10
mV/di
v,
input
60 mV
peak-to-peak
-
Repeat
the
above for
CH2,
trigger
source
CH2
Internal
Diagnostics
and
Calibration
The
9450
Internal
Diagnostics
and
Calibration
menu
is
entered
by
pressing
the "Main
Menu"
button
while
keeping
the
lowest
menu
button
depressed.
To
quickly
check
the
performance
of
the
scope,
press
the
'CALIBRATION
Constants'
button
and
then
press
'Full
Recalibration'.
It
is
advisable
to perform
this
type of
check
when
the
scope is
in
a
stable
condition
after
about
20
minutes
of
warm-up.
Then
enter
'Calibration
Error
Log'
and
you
get
a
comprehensive
summary
of
the
scope's
calibration
status.
If all
the
error
status
codes
are
zero,
it
is
very
likely
that everything
is
OK,
except
for
the
linearity
which
is
best
checked
by
'Chan 1+2
Full
Test'.
If
you
find
error
codes
different
from
zero,
you can find
more
information
on
the
problem
from
the
other
'Constants'
menus
or from
the
various
'Curves'
menus.
Before
we
turn
to
a description
of
the
menus
relevant
to
service,
let
us
give
the
interpretation
of the
calibration
error
log.
Calibration
Error
Log
This
is
a handy
tool
to perform
a
quick
and
comprehensive
internal
performance
check,
without
touching
the
acquisition
settings.
Just
push
'Full
Recalibration',
then
go to
'Calibration
Error
Log'.
The
result
displayed
is
independent
of
your
current
time
base,
sensitivity
and
other
acquisition
settings.
The
conditions
to
be
tested
are
set
automatically
during
the
recalibration.
The
error
conditions
are
coded
into
binary
bits,
i.e.
each
bit
set
represents
a
certain
error.
The
error
status
is
represented
in
a
hexadecimal
number
(4
bits
=
1
nibble)
for
each
acquisition
condition,
see
Figure 1.