Technical data
4-42 Service Guide N5230-90025
Troubleshooting PNA Series Microwave Network Analyzers
Measurement System Troubleshooting N5230C
Checking the Receiver Group
Equipment Used for These Tests
Getting Ready to Test
Before checking the assemblies, you must open the analyzer.
CAUTION Use an antistatic work surface and wrist strap to reduce the chance of electrostatic
discharge for all of the procedures in this chapter.
1. Turn off the analyzer power.
2. Unplug the power to the analyzer and disconnect all rear panel connections.
3. Remove the covers from the analyzer. Refer to “Removing the Covers” on page 7-6.
4. With the covers off, plug in the analyzer and turn on the power.
5. For Port 1 measurements, set the network analyzer for an S
11
measurement with a CW frequency of 1
GHz.
For Port 2, 3, or 4 measurements, set the network analyzer for an S
22,
S
33,
or S
44
measurement with a CW
frequency of 1 GHz.
Checking the A20 Mixer Brick Receiver Outputs
Perform this procedure if a problem appears to be in one of the receiver channels.
1. Refer to the block diagram at the end of this chapter and to “Bottom Assemblies, Options 140 and 240”
on page 6-22. Locate the flexible cables W21, W22, W23, W24, and W25 at each receiver channel
IF output, A, B, C, D, and R respectively.
2. Disconnect the flexible cable at the suspect channel.
3. Connect the spectrum analyzer to the suspect channel connector.
4. Make sure that the analyzer’s spur avoidance feature is OFF and that all front-panel jumpers are installed. The
measured signal on the spectrum analyzer should be at 7.66 MHz.
• If the measured signal is present, replace the A5 SPAM board. Refer to “Removing and Replacing the
A5 through A10 Boards” on page 7-16.
5. If the measured signal is not present on the R channel and the analyzer is equipped with Option 146 or
246, continue troubleshooting at “Checking the A29 Reference Channel Switch, Limiter, and DC Block
(Options 146 and 246 Only)” on page 4-43.
If the measured signal is not present on the A, B, C, or D channels and the analyzer is equipped with
Option 146 or 246, replace the A20 mixer brick. Refer to “Removing and Replacing the A20 Mixer Brick
(QuintBrick)” on page 7-36.
Equipment Type
Model or
Part Number
Alternate Model or Part
Number
Spectrum analyzer 8565E
856xE
a
a. Must be capable of measuring a signal at 7.66 MHz.