It's the lens/light pipe for the IR sensor board.
It turns out that while the Color Classic, 520 and MacTV are very different in board design, they share a few similarities. In particular, where the microphone board is on the CC/5XX, the MacTV has an IR board the exact same shape and size. instead of the rubber spacer to hold the microphone board in the case, the MacTV has a light pipe from this dome leading from the outside of the case. In fact, other than the fact that the 520 bezel has a rectangular hole, and the MacTV has a circular hole for the Light pipe, the bezel molding is identical. The analog board is as well, and on both the CC and 5xx analog boards, the Microphone board only uses 3 of the 4 lines going to it. The MacTV replaces the microphone board with IR, and uses all 4 wires, and thus, due to the fact that the AB in a MacTV actually says LC520, the Color classic board is jsut as well suited.
I may add stereo to the ClassicTV to bring it fully up to spec with the MacTV, but i'm still unsure.
It turns out that while the Color Classic, 520 and MacTV are very different in board design, they share a few similarities. In particular, where the microphone board is on the CC/5XX, the MacTV has an IR board the exact same shape and size. instead of the rubber spacer to hold the microphone board in the case, the MacTV has a light pipe from this dome leading from the outside of the case. In fact, other than the fact that the 520 bezel has a rectangular hole, and the MacTV has a circular hole for the Light pipe, the bezel molding is identical. The analog board is as well, and on both the CC and 5xx analog boards, the Microphone board only uses 3 of the 4 lines going to it. The MacTV replaces the microphone board with IR, and uses all 4 wires, and thus, due to the fact that the AB in a MacTV actually says LC520, the Color classic board is jsut as well suited.
I may add stereo to the ClassicTV to bring it fully up to spec with the MacTV, but i'm still unsure.