Hi RCA Ottawa
First question: how knowledgeable are you with electronics? I would start with some preliminaries, like my wife always says… “Is it plugged in?” LOL! I’m sure it is! Are there any fuses that could be blown? After that, I’d suspect a gunked up On/Off switch. Any chance you could do a continuity check on that switch, with the set un-plugged of course. If the switch fails that test try spraying some contact cleaner into the switch and cycle it on/off about 100 times. It’s usually pretty hard to get contact cleaner into a switch, so I usually drill a 1/16″ hole in the side of the switch, be careful it’s easy to damage the switch if you’re careless. Then spray the contact cleaner in through that hole. Sometimes the turntable could be preventing the radio from working if it’s stalled in play. Does the turntable operate on its own? Is the turntable able to rotate? Can you put the turntable through its cycles from play to reject, even if you have to do it manually by hand? Pictures don’t show any function switches unless I missed something. Sometimes, running through the functions a bunch of times can bring something back to life. The white powder maybe just cadmium plating oxidation. Nothing to worry about necessarily, wipe it off with a damp rag, don’t breathe it in and through the rag in the garbage.