Keysight Technologies 8481A Operating And Service Manual

Contents

Keysight Technologies 8481A Operating And Service Manual Manual pdf 60 page image

3 Service60 Keysight 8480 Series Operating and Service ManualThis is done by ensuring the power meter is providing the correct 220Hz drivesignal. Check the following levels of the square wave with an oscilloscope.– At the black/white wire: -0.05 ± 0.05 Vdc (top of square wave).– At the brown/white wire: -9Vdc (bottom of square wave).If the levels are incorrect, then the power meter or sensor cable is at fault. Refer tothe power meter service manual for troubleshooting information.If the levels are correct then the Power Sensor is at fault. Continue bytroubleshooting the A1 Bulkhead Assembly.Troubleshooting - power sensorsThe most common cause of Power Sensor failure is the application of power levelsbeyond the specified tolerance. The second most common cause of failure isapplying torque to the body of the Power Sensor. Either of these common causesdamages the bulkhead cartridge unit (which holds the thermocouples/diodes). Ifthis happens, the fault causes a short or an open between the two gold wires.A1 Bulkhead (thermocouple sensors)1 Disconnect all cables from the power sensor.2 Remove the clamp holding the two gold wires.3 Resistance measured between the two gold wires from the A1 BulkheadAssembly is listed in Figure 3-1.CAUTION Disconnect the gold wires from the A2 assembly before measuring theresistance. Be extremely careful when measuring across the gold wires. Theyare delicate and can be damaged easily.