On May 4, 10:27*pm, "Toby" wrote:
I have an Astron RS-20A, 20amp 12v fixed DC supply. I've heard that people
have modified this model to become a variable voltage supply but have not
found any schematics etc for this mod. Can anyone point me in the right
direction? Thanks!

If you will install a 2500 ohm pot between pin 5 and 6 on the
regulator chip ,that will give you variable output.. I agree with the
use of the crowbar circuit, saves damaging your equipment and damaging
the power supply too.. GL W4PQW