A minor warp in a playfield can severely affect game play. Playfields can
be successfully flattened by the following method.
Get at least two feet of 1" angle iron and three long 1/4" carriage bolts. Get
eight lock washers, eight nuts, and two flat washers all for the carriage bolts.
The tough part will be finding the places on the playfield to attach the
bolts. You'll need the round head of the bolts in hidden spot on the top of
the playfield--behind some posts, under a plastic cover, etc. It is
critical that the bolt heads be out of game play areas!
The center bolt just presses against the underside of the playfield, and is
adjustable because you can just thread it as far as you need it.
Be careful when deciding where the angle iron bar will be located so that it
won't be in the way of items under the playfield, or items on the bottom of
the main cabinet. If you have no other placement choice you may have to
relocate a relay or two, or even some assemblies.
Note that some severely warped playfields may require two or more of the
above setups to flatten out the entire playfield.