I've removed (4) screws so far, but the upper playfield is still being held down by "something". I removed the two screws that go into the right side rail, and the two that go into the top of the playfield. Are there other screws that have to be removed? Any from under the playfield? It also looks like the left side ramp metal guide needs to be removed, along with the ramp itself, but it is riveted in one spot to the left side rail?