I don't think MET has any board leds. My MET has a few insert bulbs that like to wiggle loose or have loose connections. You probably just need to push the bulb back in or adjust the bulb wires. If you bend the wires out like a 'V' it helps them make contact better. If none of that works, try to put the bulb into another location and see if the bulbs lights there. If not, the bulb is bad and easy to replace - should be a 2smd cool white wedge bulb. Look up videos on how to raise and lower playfield if you are not familiar with that. It's really easy. Just don't do any work with tools with the power on.
You should be able to access the pop bumber led from removing the cap (top part) of the pop bumper. There should be a couple of visible screws holding the cap on. Same thing, wiggle it around and push the bulb into the socket.