Tom,
now it is clear. But with anode and cathode reversed in Your first description, I could not follow.
And I was ables to complete the repair, I looked in a for-parts HP 3764A, a digital transmission analyzer, I think for T2 lines or so, which I will never need.
It has plenty of 1901-0518 Schottkys in it, and some other, similar ones.
Took two, and replaced CR3 and CR4 both.
Sidebands on the spectrum analyzer look good, but did so also with a 1N4148. Maybe it is not so critical.
Thanks for all the help.
Peter
