Agilent Technologies 8564EC Service Manual page 481

RF Section
A14 Frequency Control Assembly
20.Connect the DVM to A14J16 pin 3.
21.Change the center frequency in 1 GHz steps and confirm that the
voltage changes by 220 mV/GHz in microwave bands and
250 mV/GHz in millimeter bands.
22.Move the WR PROT/WR ENA jumper on the A2 Controller assembly
to the WR PROT position.
620 Chapter 12