Well, I think it was often the usage which was incompetent much of the time.
Dusty eht units in damp rooms...
Brian

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"David Looser" wrote in message
...

"Brian Gaff" wrote

In some later television mags, when valves were being phased out, some
enterprising folk actually made valve replacements circuits using
semiconductors on a valve base!

Plug-in semiconductor equivalents for valves were produced by the major
manufacturers for many years and widely used in professional and
industrial equipment.

As I recall, one flashover and they were history.

Only if they had been incompetently designed.

David.