Any RCA to coax converter should do, such as:
Link
I use a PS2 cable myself, the MadKatz one that fits in the back of the PS3 and converts to component cables (my TV does have an input for that).
Not sure what would have fried things before...that is odd and still a reason for concern. In my old house, I had a terrible buzzing in the system, and it turned out I was using a ratty extension cord in a bad outlet. I routed power from a better, surge-protected source, and all was well. So, make sure you are bringing in your best, consistent power, and run it all through a surge-protected power strip.