Keysight Technologies N5221A

Keysight N5221A/22A Service Guide 4-11
Troubleshooting
Power Up Troubleshooting
If All Supply Voltages are Present
If all of the supplies have measured within tolerances, and the instrument still
is not functioning properly, refer to “Front Panel Troubleshooting” on
page 4-16.
If Any Supply Voltage Is Missing
You must sequentially remove all of the assemblies, taking care to disconnect
the line power cord before each removal, and then measure the supply
voltages after each removal.
If the missing supply voltages return to a “power on” condition after removal of
an assembly, suspect that assembly as being defective.
Remove the network analyzer assemblies in the order specified in the following
steps (refer to Chapter 7 for removal instructions).
If any one individual voltage supply from the A16 power supply develops
an over-voltage or over-current problem, all supplies are affected. The
cause of the over-voltage or over-current condition can be the A16 power
supply itself, or any assembly to which the A16 power supply provides
voltage. To isolate the cause, continue to the assembly removal process as
described in the section titled “If Any Supply Voltage Is Missing” on
page 4-11.
Table 4-1 Power Supply Measurement Points
Test Point Supply Name Expected Level
(Vdc)
Test Point Supply Name Expected Level
(Vdc)
TP517 Analog Ground 0 V TP516 −5.2 V analog −5.2 ±0.1
TP509 +15 V analog +15.0 ±0.1 TP514 −7 V analog −7.0 ±0.1
TP511 +9 V analog +9.0 ±0.1 TP500 Digital Ground 0 V
TP515 +3.3 V analog +3.3 ±0.1 TP502 +5.1 V standby +5.1 ±0.1
TP513 +5.2 V analog +5.2 ±0.1 TP503 +12 V digital +12.0 ±0.1
TP501 +15 V standby +15.0 ±0.1 TP507 +3.35 V digital +3.35 ±0.1
TP504 +32 V analog +32.0 ±0.1 TP505 +5.1 V digital +5.1 ±0.1
TP512 −15 V analog −15.0 ±0.1 TP519 Digital Ground 0 V
Disconnect the line-power cord before removing any assembly.
Procedures described in this document may be performed with
power supplied to the product while protective covers are removed.
Energy available at many points may, if contacted, result in personal
injury or loss of life.