Rich,
you are not reading chapter 14 thorough enough, see page 14-3 bullet 4 which refers to chapter 3. See Table 3-1.
I'm looking in 08753-90484 Service Guide Agilent Technologies 8753ET/ES Network Analyzers.
And, I agree with your plan that you need to copy the EEPROM since option code entry does not work for you. But doing a EEPROM backup to floppy is an extra insurance. Learn from my mistakes, see
/g/HP-Agilent-Keysight-equipment/topic/49147578 Br
Marcus
