HP 8340b User Manual

7.
Adjust
A30C4
for
-8V
at
TP1.
IF
TP1
was
off
by
more
than
±3
volts
and
A30C4
is
able
to
bring
it
back
to
-8V,
it
is
likely
that the
100
MHz
VCXO
is
drifting and
A30
should
be
replaced.
If
TP1
Is
still
not
—8V,
proceed
with
step
8.
If
TP1
is
now
-8V,
proceed
with
step
13.
NOTE:
When
making
frequency
measurements
in
steps
8
through
11,
connect
the
FREQ STD OUT
from
the
frequency
counter
to
the
DUT's
EXT
FREQUENCY STANDARD
input.
If
the
instruments
are
not connected
in
this
way,
a
frequency
measurement
error may
occur.
This
error
is
caused
by
the
different
10
MHz
references
used
by
the
DUT
and the
frequency
counter.
8.
Connect
the
frequency
counter
to A30J1.
Connect
a
DVM
and
a
low
voltage
power
supply
(set
to
-0.5V)
to
TP1
(you
are
applying
a
voltage between
-0.5V
to
-8V
to TP1).
9.
Slowly
change
the
power
supply
voltage
until
TP1
measures
approximately
—8V.
While
you are
changing
the
power
supply
voltage, you
should
also
see
the
frequency
counter
reading approach
100
MHz.
If
you are
unable
to
change
the
voltage
at
TP1, replace
the
A30
assembly.
10.
Slowly
adjust
the
power
supply
for
a 100
MHz
frequency
counter reading.
Slowly
increase
and
decrease
the
power
supply
voltage.
You
should
be able
to
change
the
frequency counter
reading
above and
below
100
MHz.
If
you
can
change
the
frequency counter
as
described,
proceed
to
step
11.
If
you can't
change
the
frequency counter
reading
above
and below
100
MHz,
remove
the
A30
assembly
and
measure
the
power
supply voltages
at
the
edge
connector.
If
the
power
supply
voltages
are
incorrect,
troubleshoot
the
reference
loop
—
M/N
loop
motherboard
and the
power
supplies.
If
they
are
correct,
replace
the
A30
assembly.
11.
Turn
the
DUT
to
STANDBY
and
remove
the
A29
assembly from
the
instrument.
Install
an
extender
board
onto
the
A29
edge
connector. Measure
the
resistance between
TP1
(TUNE)
and
A29P1 pin
13.
The
resistance
should
be
approximately
370S1.
If
the
resistance
is
correct,
proceed
with
step
12.
If
the
resistance
is
incorrect,
remove
the
A30
assembly
and
measure
the
resistance between
A29P1
pin
13
to
A30P1 pin
14
and
from
A29P1 pin
12
to
A30P1 pin
12.
In
both
cases
you
should
measure
approximately
Oil.
If
either
test
fails,
check the
solder
connections
and
replace
the
wires
connecting
the
two
edge
connectors,
if
necessary.
If
both
measure
correctly,
replace
the
A30
assembly.
12.
Switch
the
DUT
ON
and
measure
the
power
supply
voltages
at
the
A29
edge
connector.
If
the
power
supplies
are
correct,
replace
the
A29
assembly.
If
the
supply
voltages
are
incorrect,
trou¬
bleshoot
the
reference
—
M/N
motherboard
and
the
power
supplies.
13.
Measure
the
frequency
and
power
output from
A30J2, A30J3, and
A30W1.
If
any
of
these
are
at
the
incorrect
frequency or
power level,
proceed
to
step
14.
If
the
output signals
from
the
above
connectors are
correct,
proceed
to
step
15.
14.
Remove
the
A30
assembly
and
install
an
extender
board. Measure
the
power
supply
voltages
at
the
A30
edge
connector.
If
the
supply
voltages
are
correct,
replace
the
A30
assembly.
If
the
supply
voltages
are
incorrect, troubleshoot
the
reference
—
M/N
motherboard
and
the
power
supplies.
15.
Measure
the
frequency
and
power
output from
A29J2, A29J3,
A29J4, and A29J5.
If
any
of these
are
at
the
incorrect
frequency
or power
level,
proceed
to
step 16.
If
the
output
signals from
the
above
connectors are
correct,
proceed
to
step 17.
16. Remove
the
A29
assembly
and
install
an
extender
board. Measure
the
power
supply voltages
at
the
A29
edge
connector.
If
the
supply
voltages
are correct,
replace
the
A29
assembly.
If
the
supply voltages
are
incorrect,
troubleshoot
the
reference
—
M/N
motherboard
and
the
power
supplies.
B-10
Reference Loop
Assembly-Level Troubleshooting
HP 8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English