2 Service68 Keysight 53147A/148A/149A Assembly Level Service GuideMethod 2Equipment RequiredKeysight 432A Power MeterKeysight 478A-H75 or 478A-H76 Thermistor MountKeysight 34401A Digital MultimeterKeysight 8120-1082 Power Sensor Cable1 Make sure the Keysight 432A Power Meter is off. Do not turn it on untilinstructed to do so.2 Set the Keysight 34401A Digital Multimeter to measure resistance, andconnect the DVM test prods between the center pin of the VRF connector onthe Keysight 432A Power Meter rear panel and pin 1 on the thermistor-mountend of the Keysight 8120-1082 Power Sensor Cable (see Figure 2-6 to locatepin 1).Figure 2-6 Keysight 8120-1082 Power Sensor Cable End View3 Round off the resistance reading to two decimal places and keep a record ofthis value as R. It is the internal bridge resistance (R) of the Keysight 432APower Meter (this should be approximately 200.3 ohms).4 Connect the Keysight 478A-H75 or 478A-H76 Thermistor Mount to theKeysight 53147A/148A/149A Power Meter OUTPUT connector, as shown inFigure 2-7.NOTE To ensure that the results are valid, the Keysight 53147A/148A/149A and thetest equipment should be powered on for at least 30 minutes prior to beginningthe calibration procedure. This allows the internal temperatures of theequipment to stabilize.6 53124
