Your PS3 set itself above the max resolution your LC-C3237U. Most likely the PS3 is doing 1080P, but the highest the Sharp can do is 1080i. So do this:
1. Connect PS3 to TV (you can use the current cable or analog cable)
2. Turn on TV and set input to port PS3 is on.
3. Make sure PS3 is connected via correct cable.
4. Power on PS3 via power button and HOLD IT for 5 seconds (release after the second beep). It should automatically configure your PS3 to the TV's native resolution for all settings.
I’m happy to assist further over the phone at https://www.6ya.com/expert/kevin_c38b47f462e94458