There is usually an inline fuse on the radio wire within 1 foot of the radio. It will be a small metal cylinder.
I am speaking generically here of what most cars of the era had on their radios. I do not know specifically what a 1950 Newport has.
Did you try turning the light switch knob with the headlights on? Did the dash lights come on? Did you take out the bulbs and check them?
When you turn on the radio it will not work until it warms up. This can take a minute or 2. If it does not work does it at least hum? If there is no hum or faint buzzing sound the vibrator is not working. This is common on old tube radios.
Your radio can be fixed if you find a tube radio expert. The parts are available. PLEASE do not butcher it for a transistor conversion.
Here is an excellent site on fixing old car radios.
http://members.cox.net/dcosby1/