G'day Ray
not thinking I'm smarter than you, but: what is the condition of the load on the 50kHz point B? Have you tried to use a temporary buffer there to isolate the load from the dividers?

Good hunting!
73, Ulrich

Ulrich N Fierz
Telecommunication Engineering Services
Zurichbergstrasse 203
CH-8044 Zurich
Switzerland
<[email protected]>