Your Philips set should have a pair of low-level audio 'monitor output' jacks on the back. These would be colored red and white for right and left channels respectively. Connect these to the 'aux' input on your Marantz receiver with a pair of patch cables, and all should work.

do I have to change any of the settings on the TV?

No setting changes need to be made if yo use the suggestion WWS944 gave you. I have been doing this for years and the sound is fantastic.

You may want to use menu settings to turn OFF the speakers in your TV set. That way you will only be using the presumably better amplifiers and speakers in your Marantz/Polk setup.

Like maryland_irisman, I have been doing this for many years. (Early 1980s - long before "home theater" became mainstream.)

what do you mean low level monitor output jacks on the back of the TV? I only see audio "in". Are you talking about the back of the cable box?

The back of many TV's have red and white jacks labeled Audio Out. But not all do.

Does your cable box have them?

If there are no "AUDIO OUT" jacks on your TV, your only option is then to use the AUDIO OUT on your cable box.

laurenjay: On the back of my Philips HD-ready TV, the audio output jacks are labeled "monitor output". There is also a menu item to turn the TVs internal speakers on/off. But if your TV only has a single set of input jacks, then it will not be feasible to hook it up. These input jacks are normally used for things like feeding a DVD player, or a video game console into the TV.

As jdbillp and criticalmass say, if your cable box has the audio output jacks, try using those.

I also made a set of jumpers that plug into the headphone jack on some tv's and fed the other end into the aux on a stereo system that does a great job too.