[volt-nuts] "*WAY* too expensive for even Keysight to redesign"

[MARVIN]

Sorry folks, sent too fast. Errors corrected. 

Yes, these folks do not market like the commercial side but there is a small industry supplying obsolete parts. They are not focused to sell to the public. Sometimes, they just hunt around for NOS stored in some forgotten warehouse, then they test components to insure like new functionality. 

https://www.rocelec.com/obsolete-semiconductor-manufacturing/ 

http://www.xtremesemi.com/company_info.htm 

http://www.rfcafe.com/vendors/components/obsolete-components.htm 

As others have suggested, it likely will not be cheap, so the cost to maintain old devices with obsolescent parts over the total cost of a redesign has to be a strong consideration.