Keysight N8973B User Manual

Keysight NFA Series Noise Figure Analyzers Service Guide 305
Power Supply/Midplane Troubleshooting
A6 Power Supply Description
Power Supply Theory of Operation
The A6 Power Supply assembly is serviced as an assembly only; no component
level repair is supported.
The A6 Power Supply assembly provides most all of the necessary DC voltages
for the signal analyzer. If any of the power supplies are not within their
operating voltages, the instrument will not function properly.
The A6 Power Supply assembly is a switching supply that operates at a
frequency of ~120 kHz.
The A6 Power Supply assembly is an auto ranging supply, requiring no user
selection of the input voltage. The input AC voltage and frequency
requirements for the A6 Power Supply assembly are printed on the rear panel
of the instruments as well as on the power supply itself.
While there are no test points or status LEDs accessible for troubleshooting on
the A6 Power Supply assembly, there are both test points and status LEDs for
all of the different power supply voltages, as well as other power supply status
lines, on the A7 Midplane Board assembly. See the “A7 Midplane Description”
on page 312 for detailed information on the location of each
Supply Voltages
The following voltage levels are produced by the A6 Power Supply assembly:
Voltage
Level
Ground
Reference
A7 Midplane
Connector
Voltage
Level
Ground
Reference
A7 Midplane
Connector
+15V SB ACOM J101 +12V D DCOM J111
+5.1V SB DCOM J111/J112 +5.1V D DCOM J109/J110
+32V A ACOM J101 +3.35V D DCOM J107/J108
+15V A ACOM J103/J104 -15V A ACOM J105
+9V A ACOM J104 -7V A ACOM J105
+5.2V A ACOM J102 FAN POS FAN NEG J101
FAN NEG FAN POS J101

Keysight N8973B Specifications

General

Brand	Keysight
Model	N8973B
Category	Measuring Instruments
Language	English