I'm sure that with today's SMD components,some "hybrids" could be made to
replace some TEK-made ICs,and get reasonable preformance,too.
Some of the TEK manuals used to have simplified circuit diagrams for TEK-
made ICs.

the 2445/65 hybrids would be tough,as they were laser-trimmed to spec on
the manufacturing line.



Probably nothing that couldn't be accomplished by adding a pot or carefully
matching components. The hard part would be getting enough info on what the
original part did. Microcontrollers would be a much greater challenge I
would think than any of the analog stuff.