Keysight N5221A Service Manual page 88

Troubleshooting
Power Up Troubleshooting
page 7-14).
7. Remove the A13 13.5 GHz synthesizer board (refer to
page 7-14).
8. Remove the A4 13.5 GHz synthesizer board, if present (refer to
Boards" on page 7-14)
9. Remove the A10 frequency reference board (refer to
page 7-14).
10. Remove the A18 GPIB board (refer to
Reinstall the A16 power supply assembly and the A17 CPU board assembly.
11. Unplug the A51 hard disk drive from the A17 CPU board (refer to
State Drive (SSD)" on page
The minimum required assemblies to power up the analyzer are:
• A16 power supply
• A15 midplane board
• A14 system motherboard
• A17 CPU board
To further isolate the failure in the three remaining assemblies, measure the resistance (with the power
turned off) from the power supply test points to either ACOM or DCOM.
NOTE Make sure that the only assemblies plugged in are the four minimum required assemblies
listed above.
Check for shorts (zero ) or very low resistance (approximately 1 ). If a short or low resistance is
measured, isolate each of the remaining four boards in the following order, and recheck the shorted test
point after each board is removed. You should be able to determine if the shorted condition has changed.
Isolate the remaining three assemblies:
• remove the A17 CPU board
• remove the A16 power supply
• remove the A15 midplane board
• This leaves only the A14 system motherboard installed. If the resistance measurements are still
incorrect, this is the suspected faulty assembly.
4-10
"Removing and Replacing the A18 GPIB Board" on page
7-46).
PNA Series Microwave Network Analyzers
"Removing and Replacing the A4–A13 Boards" on
"Removing and Replacing the A4–A13
"Removing and Replacing the A4–A13 Boards" on
"Removing and Replacing the A51 Solid
N5221A/22A
7-24).
Service Guide N5222-90001