Always let the Flight Attendant know on the flight when this happens. Back in January there was a similar post about a flight DTW-MIA that I happened to be on. The good news was their was a gate switch and aircraft switch about t-45 minutes. Went from a non AVOD 738 to one with AVOD and Live TV. The bad news, the TV's in row 1 all 4 seats did not work. We notified our flight attendant and were given vouchers for miles or $ a future flight on the spot. The person who posted a few weeks later about this in row 3 did not say anything or speak up and was wondering what he/she could do now. Sounds similar to this situation.