Power Supply Check - Agilent Technologies N5230A Service Manual

PNA Series Microwave Network Analyzers
N5230A

Power Supply Check

There are no fuses to replace within the power supply. If you determine that
NOTE
the power supply is the failed assembly, replace the power supply.
A catastrophic failure in the power supply can be determined by observing the line switch,
and by measuring the probe power at the front-panel Probe Power connectors:
1. Ensure that the instrument is plugged in with the power switch in the standby
position (power not switched on). Verify that the line switch glows yellow. A line
switch that glows yellow indicates that the +15 VDC line (P15 STB) is providing
enough voltage to light the LED. (The actual voltage may not be +15 VDC.)
2. Turn on the instrument power and verify that the line switch glows yellow. When the
line switch glows, it is an indication that the power supply has received an "ON"
command and that the +5.2 VDC supply can supply enough current to light, at least,
these lamps.
3. The front-panel probe power-connector can be used to check the +15 VDC and
−12.5 VDC (−15 VDC) supplies. The −12.5 VDC is produced by post regulating the
−15 VDC supply. Refer to
Figure 4-2 Probe Power Connector
If all of these supply voltages are missing, it is likely that the problem is either a defective
A4 power supply, or another assembly is loading down the A4 power supply. Continue with
"If All Supply Voltages Are Missing" on page
If the line switch is lit correctly, and the probe power voltages are as listed in
page 4-9, the power supply has not suffered a catastrophic failure; however, the power
supply could still be at fault. Continue with the next section to measure the individual
voltage supplies.
Service Guide N5230-90014
Figure 4-2 for a diagram of the probe power connector.
PROBE POWER
+15 V -12.6 V
4-9, to determine the cause of the problem.
Power Up Troubleshooting
sa869a
Troubleshooting
Table 4-1 on
4-7