If the EOS switches aren't working on a Fliptronics or later game, check the continuity with a DMM from the switch to the CPU board (on WPC-95), or the Fliptronics board (on earlier games). On pre WPC-95 games, these direct EOS switches go to the Fliptronics board connector J906 and the flipper opto switches go to J905. On WPC-95 games, the direct EOS switches go to the CPU board connector J208 and the flipper switches go to CPU board connector J212. Non-fliptronics games have the flipper switches and EOS switches wired directly to the flippers, and don't connect to any board.
On fliptronics games, if the flipper button doesn't register in the above test, check the flipper opto boards. Flipper opto boards were implemented on Addams Family, mid-production (some Addams have them, some don't). Also if the game uses plastic flipper opto activators, often these can warp. This will cause the activator to not clear the "U" shapped opto on the flipper opto board, causing a flipper to never energize!
On fliptronics (before WPC-95) games, there can be a very rare and unusual problem with the fliptronics board. There is +50 volts power at the flipper coils (and the coils & diodes are good), but flipper switches just don't seem to work. This can be caused by a failed flipper switch input chip at location U5 (74HCT244) on the fliptronics board.
Optos are used on fliptronics
flipper switches. Note the plastic
activator arm that moves between
the "U" shaped optos. Originally
Williams made these from metal,
but switched to plastic to save
money. The plastic version can
often warp so they don't clear
the opto, causing a flipper not
to work.
flipper switch optos
If the flipper button works fine in diagnostics, but the flipper doesn't work...
All WPC Games:
Check for +50 volts at the flipper coil. Put the DMM on DC voltage. Put the black lead on ground (metal side rail of game). Put the red lead on either of the outside lugs of the coil. A reading of 50 to 80 volts on either lug should be indicated. No voltage means (the coin door is open on 1993 or later games or) a fuse is blown, or a wire has broken.
Test the coil itself. To do this, turn the game on and leave it in attract mode. Then attach an alligator test lead to ground (metal side rail of game), and momentarily touch the other end of the test lead to the middle lead of the flipper coil. The coil should activate. This works on both Fliptronics and non-Fliptronic WPC games.
Check the flipper coil with a DMM set to ohms. With the game turned off, try this:
Notice the three solder lugs for the flipper coil. One of the outside lugs has both a thick and thin coil winding attached to it. This is the "common" lead.
Put one lead of the DMM on the outside common flipper lug (the one with the thin and thick coil windings attached to it).
Put the other lead of the DMM on the middle lug. A reading of about 4 ohms should be indicated. This is the high powered side of the coil.
Put the leads of the DMM on the two outside lugs of the coil. For fliptronics games, a reading of about 125 ohms should be seen. For non-fliptronics games, a litle more than 4 ohms should be seen until the the flipper is moved manually to the full extended position, opening the EOS switch. Now about 125 ohms should be indicated.
If approximately these readings are not seen, the flipper coil is bad. Typically the hold side of the coil goes bad more often that the power side.
Test the flipper diodes. To do this cut one lead of each diode off the coil lug. Then set the DMM to the diode setting. Put the black lead of the DMM on the banded side of the diode. A reading of .5 volts should be seen. Reverse the leads and no (null) reading should be shown. When done, re-attach each diode lead.
If the flipper works, but...

Non-Fliptronics Games:
Flipper seems to work fine, but gets very hot and eventually starts to burn and smell. Often the flipper will get stuck in the "up" position. On non-fliptronic games, the EOS switch contacts are not opening when the flipper is fully extended. Or the EOS switch capacitor has shorted on.
Fliptronics Games:
When activated, doesn't hold up (the flipper "flutters"). This means the hold TIP102 transistor for that flipper is bad, or the hold winding on the coil itself is broken. The hold winding on the coil is the thin wire. If it is broken, usually the wire has broken away from one of the solder lugs (the middle lug should have both the thick and thin wire attached to it). Test the coil first (see above) before replacing the transistor.