Service; Principles Of Operation; Troubleshooting - Keysight Technologies E Series Operating And Service Manual

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Service

Service
Service instructions consist of principles of operation, troubleshooting, and
repairs.

Principles of operation

The A1 bulkhead assembly on the Keysight E-Series E9300 power sensors
provides a 50 ohm load to the RF signal applied to the power sensor. The A1
bulkhead assembly on the E9300/1B sensors includes a 30 dB attenuator that can
be disconnected by means of a Type-N connector. The A1 bulkhead assembly on
the E9300/1H sensors includes a 10 dB attenuator in the front end. A dual range
GaAs diode pair/attenuator/diode pair assembly in the bulkhead rectifies the
applied RF to produce dc voltages (high and low ranges) which vary with the RF
power across the 50 Ω load. Thus the voltage varies with the RF power dissipated
in the load.
The low-level dc voltages from the bulkhead assembly are amplified before they
are transferred on standard cables to the power meter. The amplification is
provided by an input amplifier assembly which consists of a chopper (sampling
gate) and an input amplifier. The chopper circuit converts the dc voltages to ac
voltages. The chopper is controlled by a 220 Hz square wave generated by the
power meter. The amplitude of the sampling gate output is a 220 Hz square wave
which varies with the RF power input. The 220 Hz ac output is applied to an
amplifier which provides the input to the power meter.
The Keysight EPM series power meter automatically detects when a Keysight
E-Series E9300 power sensor is connected and downloads the correction data
from the sensor's EEPROM. In the E9300/1B/H the EEPROM contains an offset
value for the measured attenuation value of the attenuator used in the bulkhead
assembly. Thus, the attenuator is matched to a particular sensor. The
auto-averaging settings are also configured automatically for use with Keysight
E-Series E9300 power sensors. This configures the power meter to operate over
the range with that particular sensor's unique correction data applied.

Troubleshooting

Troubleshooting information is intended to first isolate the power sensor, the
cable, or the power meter as the defective component. When the power sensor is
isolated, an appropriate Sensor Module must be used for repair.
54 Keysight E-Series E9300 Operating and Service Guide