Keysight Technologies N5247B, Service Manual

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Keysight N5247B Service Guide 4-43
Troubleshooting
Measurement System Troubleshooting
Checking the A26 Splitter Output
1. Refer to the block diagram at the end of this chapter and to “Bottom RF
Cables, Standard 4-Port Configuration, Option 401, S/N Prefixes <6201”
on page 6-87 . Locate the semi-rigid cables W53 and W54, at the A26
splitter.
2. Disconnect W53 and W54, one at a time, from the A26 splitter.
3. Connect the spectrum analyzer to the open connector.
4. Refer to the NOTE notice on page 4-29 . Set the network analyzer for an
800 MHz CW frequency and observe the spectrum analyzer measurement.
For analyzers with DSP version 4.0, an 807.61 MHz signal should be
present. For analyzers with DSP version 5.0, an 807.44 MHz signal should
be present.
5. If the observed problem was frequency banded rather than broadband
related, set the analyzer frequency to the center of the problem band. The
spectrum analyzer should measure a signal above the network analyzer
setting. For analyzers with DSP version 4.0, the signal is 7.61 MHz above
the network analyzer setting. For analyzers with DSP version 5.0, the
signal is 7.44 MHz above the network analyzer setting.
6. If the signal is not present but the signal from “Checking the A25 HMA26.5
Output,” is present, replace the A26 splitter. Refer to “Removing and
Replacing the A26 Splitter” on page 7-39 .
7. If the signal is present, reconnect cables W53 and W54, and then continue
with “Checking the Receiver Group” on page 4-52 .
Checking the A4 and A17 Source Synthesizer Outputs
1
1. Refer to the block diagram at the end of this chapter and to “Top Cables,
All Cables—All Options, S/N Prefixes <6021” on page 6-21 . Locate either
the cable W1 at the A4 source 1 synthesizer board or W2 at the A17
source 2 synthesizer board. (W2 and A17 are only available in 4-port
models and 2-port models with Option 224.)
2. Disconnect W1 or W2 from J1207.
3. Connect the spectrum analyzer to J1207.
IMPORTANT! Some PNAs have installed a legacy HMA26.5 (5087-7765)
that is used with a discrete A26 splitter. Some PNAs have installed a new
HMA26.5 (N5240-60101) with an integrated splitter. To identify which
HMA26.5 is installed in your PNA, refer to Figure 4-12 on page 4-42 .
1. A4 and A17 synthesizer boards only applies to PNAs with serial number prefixes
<
6021.