Are they mechanically stuck? Move them up by hand and see if they get stuck.

If so check for any binding or just give the mechanisms a good cleaning.

There is a flipper board on the inside left of the cabinet under the playfield with five fuses on it. I would star by metering and possibly replacing those fuses.

This may help a bit:

Flipperchart.gif

Not sure if this is the same problem. Check the leaf switch for the flipper button, its mounted close to the ball launch coil. When the playfield shifts a little inside the cabinet it bumps into the coil causing the upper flipper to activate. Mine did the exact same thing a few weeks ago after moving it and that was the problem.