Without model numbers we can't know what connections you have.
1. HDMI (video & audio) best picture and sound
2. Component Video (3RCA) plus audio (2RCA)
3. Composite Video (1RCA) plus audio (2RCA)
Some TVs have a shared component composite video input. Set it in the TV menu.
You might need a converter to change from one to the other.
A new BD player would be a better option since even you old discs will look better played on it.