I'm a Finnigan "Navigator " user, and I run in a similar problem which
I still did not solve.
Turbo pumps show 100% speed, pirani gauge show 8.3E-05 vacuum; but
still the amber light of vacuum is lighting up quite often with not
apparent reason.
I'm looking for information on which parameter is used by electronics
to drive vacuum light status.
sincerely
Adolfo