30 Jul
2026
30 Jul
'26
8:31 a.m.
On Jul 30, 2026, at 7:16 AM, Tony Duell via cctalk
<cctalk(a)classiccmp.org> wrote:
On Thu, Jul 30, 2026 at 12:05 PM Christian Corti via cctalk
<cctalk(a)classiccmp.org> wrote:
Indeed. This one example seems utterly bizarre, and I suspect may be the only instance of
this sort of thing. "Soft vacuum" tubes doesn't sound very sensible, though
of course gas filled tubes are common (thyratrons and ignitrons, not to mention mercury
vapor filled rectifiers like the famous 866).
paul
On Wed, 29 Jul 2026, Carey Schug wrote:
Perhaps you should learn the very old-fashioned way of valves/vacuum tubes :-)
There were some very early triodes that deliberately contains residual
gas. See here
https://www.museumoftechnology.org.uk/objects/_expand.php?key=954
There was a little side/top tube containing asbestos that you heated
to release some of said gas that was adsorbed onto the asbestos.
So yes, some valves _do_ contain asbestos. But it would only be a
hazard if the glass was broken.
And if such a valve was ever used in any DEC computer or peripheral I
almost say I'll eat a PDP11! i wondered, and ai confirmed, that vacuum tube
computers likely
contained asbestos, but suggested in the vacuum tubes, so probably not
Go back to school and learn the old-fashioned way. Never trust AI, always
verify the results.
Asbestos _in_ vacuum tubes ... *lol*