Agilent Technologies 8590 Series Service Manual page 423

TREE 1: Spectrum Analyzer Platform vs Option 190
IS THE PROBLEM A SPECTRUM ANALYZER PLATFORM OR OPTION 190
Comments
Spectrum
Analyzer Platform
Problems
Sometimes an
Option 190 problem
can look like a
spectrum analyzer
failure.
Chapter 10
First LO Distribution Amplifier (LODA) 8593E, 8594E, 8594Q, 8595E, 8596E Option 009
PROBLEM? (Continued)
Problems/Reasons
One or more power supply
voltages can be shorted to
ground.
High spurious in noise floor, or
showing up in spectrum
analyzer residual FM test.
No signal on screen.
Analyzer Options and Block Diagrams
Diagnostic/Fix Action
Detach and remove the Option 190 card
cage boards, one at a time, in the
following order: DSP, DEMOD, and RF
card. After each card is removed, power
up the instrument and look for normal
spectrum analyzer behavior. The short
is probably on the last card you
removed.
The Option 190 cards have many
high-speed clock signals, and high
amplitude oscillators. Sometimes these
signals are coupled into the main
spectrum analyzer path, and seen as
spurs.
1. Check the Option 190 80-pin ribbon
cable for good seating in its
connector.
2. Check the Option 190 gray coaxial
cables for good seating in its
connector.
3. Check for proper routing of cables.
Refer to the Service Guide.
The Option 190 RF card has an
electronic switch that flips between the
input signal to the spectrum analyzer
path, or the Option 190 RF card input.
This switch may be broken, or frozen so
that the input signal never reaches the
spectrum analyzer path. Remove the RF
card. Reconnect the 321.4 MHz path as
in an 8594E spectrum analyzer. Check
for a trace on screen.
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