J
... qualified engineers are less of an issue these days.
Not in my experience! There is a distinct lack of knowledgeable engineers these days, particularly with in depth x-ray equipment. Even amongst the big players in the market the experience of the engineers is not what it once was.
There are few who are suitably qualified and knowledgeable enough to be able to procure an exact replacement that is as good as the original. Even if they obtain an exact replacement the installation and setting up can be an issue. I have seen some tubes fitted physically and left without any setting up of the filament currents being performed!
There may be some using this site who can and are able to perform the work correctly and safely but there are many who will read this and assume there is no big deal in obtaining a 3rd party replacement.
Again those selling 3rd party replacements have an agenda of their own to sell more goods so will 'talk up' the benefits of their products and services and quote the 'high' prices of the OEM. Therefore a more moderate approach to both sides should be taken before a decision is made to purchase 3rd party or OEM products and services.