4-40 Keysight N5227B Service Guide
Troubleshooting
Measurement System Troubleshooting
4-
Checking the A56, A57, A58, and A59 70 GHz Doubler Outputs
1.
Refer to the block diagram at the end of this chapter and
Configuration, Option 419” on page 6-93
. Locate the following cables.
(Boards A61 and A62 are available only in 4-port models and 2-port
models with Option 224.)
—
W27 on the A60 doubler board,
—
W28 on the A61 doubler board
—
W29 on the A62 doubler board
—
W30 on the A63 doubler board
2.
Disconnect cable W27 or W28 or W29 or W30, depending on which
doubler board is to be checked.
3.
Connect the spectrum analyzer to the open connector on the doubler
board to be checked.
4.
Set the PNA for an 800 MHz CW output frequency and observe the
spectrum analyzer display. An 800 MHz signal should be present.
5.
. If the PNA problem you are
troubleshooting is frequency banded rather than broadband related, set
the PNA output frequency to the center of the problem band. The
spectrum analyzer should display a signal above the PNA 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 signals described in
and A17 Source Synthesizer Outputs” on page 4-38
are present, replace
the appropriate doubler board. Refer to
A60–A63 70 GHz Doublers” on page 7-54
.
7.
If the signal is present, reconnect all cables, and then continue with
“Checking the Signal through the Signal Separation Path” on page 4-43
Checking the A70/A75 Low Frequency Extension (LFE) Board and the Bias
Combiners
The 2-port and 4-port Low Frequency Extension (LFE) options add additional
hardware to extend the start frequency of the VNA down to 900 Hz.
