Frequency; Power (15 - HP 8340B Manual

FREQUENCY
(14)
If
the
UNLK
annunciator
is not on, and the
RF
output signal frequency is
incorrect, refer to Section IV
Performance Test, Frequency Range and
CW Mode
Accuracy. This test checks
all
of the divider bits
that program the various phase lock loops. The test indicates
which phase
lock loop is
causing the
problem
and which
bit
or
bits are
incorrect. After you isolate the faulty
loop, refer
to the appropriate
functional group troubleshooting.
POWER (15)
The RF output
should
meet
the specifications for maximum leveled power, power accuracy, and
flatness.
Maximum Leveled Power
For problems related to maximum leveled power, refer to
UNLEVELED ANNUNCIATOR.
Flatness
NOTE: Before performing the
following procedure, use the SHIFT M4 diagnostic test to help isolate
the cause of
an incorrect
power condition.
1.
The
flatness adjustments
in
Section V, Adjustments, improve overall flatness by varying the offset
and slope correction factors.
If
the frequency response has large variations, the problem
is
proba¬
bly
in the
associated RF path. Refer to the RF section
functional
group.
2.
If
the
RF power
level
is
low at
10
MHz and increases with frequency, suspect the
RF
output
connector. This connector contains
a
series capacitor that
can exhibit this
symptom. To
verify
that
the problem is
the RF connector:
a.
Remove
the front panel (see the front panel
—
rear panel functional group).
b.
Disconnect the
SMA
cable to the
RF connector, and remove the RF connector.
c.
Measure the power level at the cable.
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|
CAUTION
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Be extremely careful when disconnecting or
connecting
an
SMA cables
from
a
mating 3.5 mm connector (RF attenuator). The SMA cable center
conductor must
align with
the
3.5
mm connector center conductor.
If
there is any axial force
on
the cable when disconnecting the
SMA
fitting,
the 3.5
mm connector center conductor can be
damaged. Remove any
axial force on the cable by first disconnecting the end of the cable that
does
not mate with the 3.5 mm connector, or by removing the mounting
screws of the device
having 3.5 mm connector.
HP 8340B/41B
Assembly-Level Service Overall Instrument Troubleshooting A-43