Certain early solid state Williams
Pinball Machines came from the factory with non replaceable coil
stops. When these coil stops wear out the entire flipper base
plate needs to be replaced.
Scorpion, Algar, Alien Poker, Barracora, Black Knight, Cosmic Gunfight,
Defender, Firepower II (some), Joust, Jungle Lord, Pharaoh, Solar Fire,
Time Fantasy, Warlok.
modification allows you to use the existing flipper base plates, retain
original flipper geometry, and use replaceable coil stops.
Instead of the modification listed here another option is to replace
the entire base and mechanisms with the
newer WPC style flippers. This is a good way to get
stops - and all the WPC flipper parts are readily available from many
sources. However, this does not keep the
original flipper geometry and also requires changing the flipper bats
to WPC style.
After this modification, the flippers can be serviced using WPC coils
stops, links, and plungers. But also
retain the original coils, bats, and geometry.
In addition to what is listed in this guide, I also enlarged the hole
in the factory flipper pawls to accept a #10 bolt. This allows
you to use WPC style flipper plungers and links.
After doing this to both flippers on
Firepower the flippers now work great. Making the lock at the top
of the playfield via the left spinner is easy - plenty of flipper
Below is how to do the modification.
Here is a pic of the removed factory
base plate. Note the worn coil stop. Next to the plate is
the WPC style coils stop.
First Step is to bend the coils stop portion so it is flat
relative to the rest of the plate. I did this in a vice. I
also applied heat from a propane torch to help the metal bend without
cracking. Not sure if this is necessary but why not. Go
Here is the result. Notice that the it is not completely
flat and the mounting tab is a little out of alignment.
So here I straighten it out a bit. You could also use a
hammer and a flat surface to do the same.
Then cut off the excess metal. Cut just below the original
Now using a coil and WPC coil stop, mock up the assembly and
mark where the holes need to be drilled and tapped. Center punch
the holes for the coil stop, take everything back off the plate, then
drill and tap holes.
Here I am tapping the holes to accept #10 32 bolts.
Now it is done and ready to put back in the game.