66 C10 won't start

[Black66]

My truck has been giving me problems lately. A few days ago it would fire up fine but occasionally I would turn the key and I would get nothing. No crank at all. My accessories would come on, radiator fan, lights, radio, etc. I'd then fiddle with the key turning it off and on pushing in and out on the clutch and eventually it would crank instantly. I thought it was the starter so I took it into Advance Auto Parts and the guy put it on the bench and it spun fine.

Now I put the starter back on and tried to start it up again, nothing happened but the accessories came on as usual. I tried it one more time and this time the radio made a noise like it was rewinding a tape and now I have no power whatsoever. I'm taking in the alternator and battery to Advance and seeing what they say.

Is there something I'm missing that could be bad?