Where is the ir senser on a dvp725d

It should be in the dark plastic area. Shine a flashlight in there and look for the IR receiver. You should see it easily. Otherwise, take the remote and get a piece of card board and cover the entire plastic area. Then start aiming the remote and clicking it to do something it can do. When the IR receiver is uncovered it will do something. Remember the area and shine the falshlight in there and you will see it.