The signal generator is now working. I came to understand that the multiplier is a T attenuator used to maintain a stable amplifier load and output impedance. It can also offer more isolation. Using an ohm meter, it is logical that I would see similar resistance readings on all switch settings, and that resistance reading would be the expected load impedance.
My problem was three-fold. 1 - I did not have a full understanding of the purpose of the multiplier circuit, 2 - there is a missing external load selector circuit, and 3 - I had inadvertently swapped the LO RF and HI RF output jack shielded cables when placing the assembly back in the signal generator. The latter mistake only further confused the matter. The missing load selector circuit must have been in a probe or external housing. Once I connected a .047uf capacitor to the LO RF output jack as a test, the scope displayed the signal as expected - in all cases.
The multiplier circuit is the following:
Triplett 3433 Multiplier.jpg [ 46.88 KiB | Viewed 122 times ]
The multiplier assembly is boxed in blue, the missing output load selector is boxed in green and the swapped output jacks are circled in red.
I am sorry that I may have caused you to waste time in analyzing my questions. It was due to my lack of understanding of the T attenuator's purpose. I am very happy to report, however, that all is working just fine now.
Thank you all again!