is my servo faulty
 

need advice just getting back into things after 20 years so a bit rusty on new tech, i have 3 steering servos 2 acoms and 1 futaba they acoms do not seem to work with the esc but the futaba one seems to work fine ive checked them on 2 different receivers and controllers, i was just wondering do i have 2 faulty servos or am i missing something having been out of the game for so long, thanks in advance

I don't know for sure but I would guess that your acoms are analogue and futaba digital? Otherwise its highly likely they have just seized up or brushes have corroded.