I'm wondering how many others of you have seen defective operation,
sooner or later, or other deterioration in your high current regulated
DC supplies?

And, if the overvoltage crowbar craps out, it blows up your rig? I'm
thinking of going exclusively back to deep cycle marine batteries, again.
====================================
The crowbar is there to NOT blow up your equipment.

However operation of a crowbar should blow a fuse fitted 'upstream' of
the pass transistors. As already explained earlier in this thread ,the
crowbar should also be fitted 'upstream the pass transistors (but
'downstream' the fuse , while sensing the output voltage .

If the Astron voltage regulator would be suspect I would recommend a
very simple circuit with a 7812 voltage regulator and a PNP transistor
,its output 'steering' the pass transistors .

Ref : Experimental Methods in RF Design , by W7ZOI-KK7B- W7PUA
page 1.15


Instead of the 3 legged 7812 you can also use the similar LM317 enabling
output voltage adjustment
After all this is a homebrew NG

Frank GM0CSZ / KN6WH