Vizio 50'' Plasma AV1 & 2 Ports Unresponsive

Question

I have a PS2 that I've been using on this TV via the AV1 port for about 2 years. Suddenly about a week ago, all I get is No Signal when I turn on the PS2. I tried AV2 with the same result. I've tried a friend's PS2 and cables with the same result. Both PS2s work on another TV just fine. Is there something I'm missing or is this a main board problem that I'm going to have to replace?