[KYHAM] Astron as a float charger?

[Tyler Allison]

So I figured I'd attempt a bit more learning this afternoon and decided to
open up my Astron power supply and tinker with it a little bit. Having
only attempted one other soldering job in my entire life and only a
Technicians license worth of electronics training this seemed like a
reasonable thing to do ;)

Following the instructions found here:
http://www.repeater-builder.com/astron/astron-rsbattmod.html

and the schematics found here:
http://www.repeater-builder.com/rbtip/astron-index.html

I believe I've modified my Astron power supply to act as a float charger
for my very large battery system.

It only involved a single resistor (5 for $99 at ratshack), a sharp knife
and a couple taps of my soldering iron.

Everything powered on okay after my modification.  Batteries are taking a
charge. Ham radio works.  Wheww...didnt kill myself.

Now the question is how do I test that the resistor is doing it's job of
protecting the regulator chip when AC power fails without frying something
or myself?

Is it as simple as yanking the power cord out of the wall and putting a
volt meter on either side of the resistor?

Thanks!

-Tyler/KI4BUM