If I recall correctly, the small coil pulls the square latch Inwards to drop the ramp. It does not hold it up, rather a lip or protrusion should rest on top of the square latch plate. When the plate is retracted by the small coil, it basically falls off of a ledge and the ramp drops.

With the game off, can you physically get the ramp to lock in the up position? If not, problem could be with the larger yellow coil, it might not be pulling far enough to lock the arm in place. Check the coil sleeve and make sure the plunger can slide freely all the way through. If that's not it, probably something wrong with the lock arm mech. It's definately not the small coil, like EE said, that's for dropping the ramp down.

Edit: Also check the switch near the yellow coil (with the bend arm). When the ramp is up, the switch should be open...but if it's misaligned or the bend arm isn't set right, it might be keeping the switch close...making the pin think the ramp isn't up. It will fire 5 times trying...then quit.

You may also want to look at metal brackets/swivels for wear.I had a similar problem and had to diamond file the bracket a bit for smooth operation.Move it around with the power off.