72 Factory Radio fix?

Hello FABO, my 2 knob factory AM 72 scamp dash radio does not operate and I would like to fix it. The light goes on with the headlights, as far as I can tell its hooked up and the fuse is good. However nothing comes out of the speaker, what is the best diagnosis procedure? Is there a common issue to look for?

Secondary question, if it comes to it whats the easiest way to get it out? I have dug around with the AC controller and its pretty miserable getting back in there. The AC vents prevent access from the bottom.

Thanks for any leads!