4-20 Service Guide N5230-90014
Troubleshooting PNA Series Microwave Network Analyzers
Rear Panel Troubleshooting N5230A
Rear Panel Troubleshooting
Each rear panel connector is associated with a hardware group in the analyzer. You can 
use the data at these rear panel connectors to help troubleshoot these hardware groups in 
addition to testing the connectors.
The connectors discussed in this section are:
•USB
• SERIAL (RS-232)
• PARALLEL (1284-C)
•VGA
•GPIB
• LAN
Checking the USB Ports
NOTE
The rear panel contains five USB ports; one “stand-alone USB port” on the 
CPU board and a “group-of-four” connected to a separate hub.
To verify proper operation of any USB port:
• Connect a known good USB device, such as a USB mouse.
• Wait 15 seconds for the analyzer to verify the device connection, and then check the 
operation of the USB device.
• If the device performs correctly, the USB port is functioning properly.
• If the device does not perform correctly, remove the non-working USB device, wait 15 
seconds, and then reconnect the device to the USB port.
• If the device still does not perform correctly, remove the USB device and connect it to 
the front panel USB.
NOTE
If the front panel USB port does not work, refer to “A3 Front Panel Interface 
Board” on page 4-19.
• If the USB device has been verified to work on the front panel but not on the 
stand-alone USB port:
— Then the A15 CPU board is faulty. Refer to “Removing and Replacing the A15 CPU 
Board” on page 7-20.
• If the USB device has been verified to work on the front panel but not on one of the 
“group-of-four” USB ports:
— Then the rear panel hub is faulty. Refer to “Removing and Replacing the A16 Test 
Set Motherboard and the USB Hub” on page 7-22 for replacing the rear panel hub 
board.