I had a couple of doghouse blue Tek scopes I gave away to a guy, who
wound up parting them out and building some very crude tube audio stuff
he charged a lot of money for to gullible idiots in St. Louis. That
town appears to be a haven for audio con men.

The old Tek scopes are either too much work to keep going, or have
mostly been used so heavily they are no longer usable. There are no
more parts for DESIRABLE Tek scopes! Tek has not made an actual
oscilloscope in nearly ten years and the last ones (the TAS series)
were crude and nearly unusable.

Large quantities of certain parts do exist-because either those are
the parts that don't go bad or they are for stuff you don't want
anyway.