Rebuilding a Funhouse

Trapdoor metal tongue broken - ball gets stuck on trapdoor

I did this repair once already on my home Funhouse, so I had a good idea of how to do it this time. The first step is to remove the trapdoor from the playfield, so it's easier to work on. Since I had repairs to do to the trapdoor lift mechanism as well, I started by removing that (three screws). Then the two nuts holding the trapdoor down are removed, and it's free.

[trapdoor with original broken tongue] Here's the trapdoor out on a workbench, with a piece of metal that looks like it used to be the other half of the tongue. There were a couple different flaps like this one lying in the cabinet - almost as if they break on a regular basis. After this repair I found out from Steve Young at The Pinball Resource that there's a factory-authorized fix for this - a little metal thing that screws to the bottom of the playfield under the trapdoor to support it when it's closed, to take the stress off the flap. Sounds like a good idea...

[trapdoor rivets drilled] Two quick shots with the drill, and the original rivets are cleared out. They'll start spinning as they loosen up, so you might have to invent a way to keep them from spinning too much. You can also stop drilling before you get to the metal of the trapdoor itself, and use a small nail to punch the remaining rivet out of the hole.

[new flap going in] Here's a new flap, made out of a different type of metal. I had a pile of transformer laminations lying around, which are a thin, fairly stiff steel, though not the same as the blueish spring steel of the original flap. After cutting the metal to the proper size I ran the edges down with a wire brush to make sure there were no sharp edges to chew up the playfield.

[new screws going in] Now we put in a pair of #4-40 flathead screws. The heads will stick up a bit more than the original rivets, but since the ball travels down the center of the door, they don't actually get in the way. Underneath we have nuts with lockwashers.

[side view, finished] Here's a side view of the finished installation. From here you can see how much the screw heads protrude up above the playfield surface - not much, really. Once the game is back together the ball rolls right over it. If there's any obstruction, it's certainly less than when the ball got stuck on the door before this repair.

[playfield, finished!] Here it is back in the playfield! Notice the gouging from where the last trapdoor flap used to hit the playfield - by keeping the new flap fairly flat on the playfield, and making sure it's free of sharp edges, this shouldn't happen as much.

Getting the door back into the playfield turns out to be the hardest part of the whole process. I started by mounting the trapdoor to the playfield, and then trying to get the crank back into the trapdoor. After wrestling with it for 10 minutes or so, I gave up and bent the new flap out of the way by pressing the trapdoor under the playfield, getting the lifting crank back into the trapdoor, and then repairing the bent flap. There's gotta be a better way, but I seem to recall this is how I did it last year on the home machine too.

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last twisted 9/18/97 by tom