Help with Magnavox my surround sound
 

I have and older Magnavox tv and a Sony Am FM surround sound and a Sony DVD player all hooked to the tv with RCA cables, everything worked fine for years ( no cable ) , just streamed everything from Roku and and through the DVD player. Last week my wife wanted to get cable turned on. The cable company came and installed two boxes for the cable and now my surround sound DVD player and Roku will not work " communicate " if you will " with my tv. So my question is what setting up the cable setting do to the setting in my tv. The cable company was no help at all they said buy a new tv

You're going to have to be a heck of a lot more specific about what's going on for anyone to help you.

Ideally, describe the signal chain that you originally had, and then describe exactly how things are currently connected.

If you can't do it in words, then draw a map with pen and paper and attach a picture of that map to a reply.

People here will try to help if we know what's going on.