Fluke 6060B Instruction Manual page 154

MAINTENANCE
troubleshooting and
repair
The
four groups (denoted by the
A's,
B's,
Cs
and
D's) in the
seif-test
report correspond
to
different
test
categories.
These
tests are
described below, including a tabulation of the
Generator instrument
state
and
the
test
codes
that
result
if
any
test fails
to achieve the
expected
result.
Understanding
how
these
tests
are
done can provide
more meaning
to the
results
and can
assist in
understanding
how
they
relate to other
symptoms.
A
successful
self test
is
reported with
all
zeros.
During the
self test,
the step
attenuator
is
programmed
to
maximum
attenuation and
the
internal
frequency
reference
is
selected.
The
analog
circuit tests
make
use of the unleveled
(UNLVL)
and unlocked
(UNLOK)
status detectors, whereas
the
digital circuit tests
make
use of write/read techniques.
4D-18.
AAA
FIELD
AAA
is
the result
of
the
AM
and
FM
tests.
During
these
tests, level
correction
is
applied.
During
the four
AM
tests,
a
normal
AM
depth,
which should produce
a
leveled
condition,
and
an abnormally
high
AM
depth,
which
should provide an
unlcveled
condition,
is
set for
each
modulation
frequency.
During
the
two
FM
tests, a
normal
FM
deviation
is
set,
which
should
produce
a
locked condition, and
then
an abnormally
high
deviation
is
set,
which should produce an unlocked
condition.
The
two
FM
tests
are not
performed
if
the
Option
-^5
1
Low-Rate
FM
is
installed.
Table 4D-3 shows
the
AAA
Field
AM
and
FM
tests.
4D-19.
BBB
FIELD
BBB
is
the
result
of the synthesizer
tests.
In the
first
three
test steps,
the Synthesizer
assembly's
main
PLL
operation
is
verified
by
programming
a large
change
in
frequency.
This should cause a
momentary
unlocked condition
that
should
clear as
the frequency
settles to the
new
frequency.
Table
40-3.
AAA
Field
AM
and
FM
Tests
AAA
(CODE)
1
LEVEL
(DBH)
,
AM
(X)
MOD FREO
CHZ)
KV
DAC
FM
DAC
FM
RANGE
EXPECTED
RESULT
001 1050
10.7
;
30
1
400
n/a n/a n/a
Lovolad
1050
!
u
' 127
1
400 n/a n/a n/a unleveled
BiLH
1050 10.7 30
1000 n/a n/a n/a
Leveled
010
'
1050
U
127
1000 n/a n/a n/a
Unleveled
280
-10
n/a 400 Normal 1023
4
Locked
280
-10
n/a
400
1023 1023
4
Unlocked
In
the next three
steps,
the synthesizer
is
checked by
programming
225
MHz,
which
is
outside the
normal
operating frequency range, and
should
result in
an unlocked
condition.
Then
385
MHz
is
programmed, which
should
result in
a locked condition.
Next
550
MHz
is
programmed, which
is
again outside the normal
range,
and
should
result in
unlocked
condition.
Finally,
all
frequency
reference circuitry
is
turned
off,
which should produce an unlocked
condition, and
then turned on,
which
should produce a locked
condition.
Table
4D-4
shows
the
BBB
Field
test results.
4D-20.
CCC
FIELD
CCC
is
the
result
of
the digital
tests.
The IEEE^88
option
(if
installed)
is
verified by
writing
data
to the
IEEE^88
chip,
A3
A3U
1
,
then by reading
it
back and checking
for the
expected
response.
Each
memory
location
of
the
Non-Volatile
RAM
is
checked with a
checksum.
4D-6