If they're blinking when he screen moves the lamps are good.
Be careful and go slow to not scratch the back of the bingo card when removing/installing it.
Trouble is likely the socket(s) - after cleaning the inside bright and shiny, pull on the center nub for more protrusion.
A VERY slight bending on the outer socket with a screwdriver will ensure a snug fit.
Test all of them before buttoning her back up.