Astron Power Supply Crow-bar Circuit Operation

: 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?

Happens more with the older supplies... part values change with time.

: 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 .

I don't agree...

: 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

Not a good idea... regulation really suffers bad.

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

No good... if you're only trying to get in the ball park maybe... if
you plan to use and trust the supply with expensive equipment you should
stick with an LM-723 or similar circuit properly designed using the mfgrs
data sheet information.

cheers,
skipp